Glossary extracted starting with manual seeds, with PTM for the domain phy and language EN

stationary wave	A standing wave; the pattern formed when two waves of the same amplitude and frequency move simultaneously through a medium in opposite directions
troposphere	Lowest level of Earth's atmosphere, from zero altitude to about 15 km above the surface
schwarzschild filling factor	Ratio of the actual density to the limiting value for a system
astrophysics	(a) The science that studies the physics and chemistry of extraterrestrial objects
divalent	Binds to two other things (which may be other atoms, molecules, ions, or electrons)
multi-doughnut	Also, Multi-Handled Doughnut
excitotoxin	An excitotoxin is a toxic molecule that stimulates nerve cells so much that they are damaged or killed
taylor column	A column that occurs over a fixed region in a rotating fluid because of the two-dimensional character of the motion in the absence of viscosity
carrier signal	electromagnetic wave whose modulations are used as signals in television and other radio transmissions
lumen	Symbol: lm -- The SI unit of luminous flux, equal to the luminous flux emitted by a point source of one candela in a solid angle of one steradian
trac	Transient Radiation Analysis by Computer
abundance ratio	The ratio of the number of atoms of an isotope to the number of atoms of another isotope of the same element in a sample
effective area	The unrestricted collecting area of a telescope after obstructions in the optical path have been taken into account.
ozone layer	A layer in the Earth's atmosphere at 15-30 km altitude in which ozone is at higher concentration than at lower or higher altitudes
gravity	A physical force that appears to exert a mutual attraction between all masses
isochoric	Having constant volume.
quantization	The restriction of various quantities to certain discrete values; or, more generally, to deriving the quantum-mechanical laws of a system from its corresponding classical laws
photon	A particle of light, unit of electromagnetic energy.
opnav	Optical Navigation (images).
magnetic field	The region of space around a magnetic body or a current-carrying body where objects can be affected by the magnetic forces due to the body or current.
van der waals forces	(a) Attractive forces existing between molecules
4n nuclei	Nuclei possessing equal and even numbers of neutrons and protons
conservation laws	Laws that identify a quantity, such as energy, that remains unchanged throughout a transformation
fusion	See Nuclear fusion.
carboxyl group	Also called the COOH group; functional group consisting of a carbon atom double bonded to an oxygen atom and single bonded to another oxygen with a hydrogen on the other side
unit cell	The simplest arrangement of atoms or molecules that regularly repeats in a crystal structure.
stark effect	Line broadening due to the influence of electric fields.
r-process	The creation of elements heavier than zinc through the rapid bombardment of other elements by neutrons
primary barrier	Barrier sufficient to attenuate the useful beam to the required degree.
aristotelian physics	Physics as promulgated by Aristotle; includes the hypothesis that our world is comprised of four elements, and that the Universe beyond the moon is made of a fifth element and so is fundamentally different from the mundane realm
electron volt	A unit of energy, sufficient to excite atoms to emit visible light
densitometer	A device designed to measure the optical density of an exposed and processed film
head	See coma
artefact	material object modified purposefully for use by the person or animal that does the modifying
acidic solution	A solution in which the hydrogen ion activity is higher than that of the hydroxide ion, when the solvent is water.
ground segment	All the facilities and systems required on Earth to control and operate a space mission.
fds	Flight Data Subsystem.
thought experiment	An experiment that cannot be or is not carried out in practice, but can, given sufficient imagination and rigor, be reasoned through by thought and intuition alone.
ksc	Kennedy Space Center, Cape Canaveral, Florida.
chromospheric network	A large-scale cellular pattern along the boundaries of which lie bright and dark mottles seen in H and other regions
occultation	The cutoff of the light from a celestial body caused by its passage behind another object.
charge	The fundamental property of a particle that causes it to be affected by the electromagnetic force
ipc	Information Processing Center, JPL's computing center on Woodbury Avenue in Pasadena.
rosat satellite	A German X-ray astronomy satellite with US and British collaboration that was launched in 1990.
rare gases	The inert gases He, Ne, Ar, etc.
usafsd	U.S
2 test	A least-squares statistical test that measures the probability of randomness in a distribution
mfp	Mean Free Path
hst	Hubble Space Telescope
holomorphic	Same as complex analytic
fertility	The ability to have children
opacity	Absorbing power; capacity to impede the passage of light.
genome	The complete genetic information of a species.
pathologist	A doctor who specializes in identifying diseases by studying cells and tissues under a microscope.
reducing atmosphere	atmosphere comprised of substances that readily provide electrons
optical interface	Interfaces must be mechanically and optically defined
moonrise	For technical definition, please follow this link to the U.S
look-back time	(a) Phenomenon that, owing to the finite velocity of light, the more distant an object being observed, the older is the information received from it
induction	System of reasoning in which the conclusion, though implied by the premises and consistent with them, does not necessarily follow from them.
chondrules	Small spherical grains varying from microscopic size to the size of a pea, usually composed of iron, aluminum, or magnesium silicates
copolymer	A polymer composed of two or more different monomers
reagent	A substance or mixture that is useful in chemical analysis or synthesis.
survivorship	Living with a history of cancer, from the time of diagnosis on, regardless of the treatment outcome.
rods	The more sensitive cells of the retina of the eye
geodetic coordinate	The latitude and longitude of a point on the Earth's surface determined from the geodetic vertical (normal to the specified spheroid)
ius	Inertial Upper Stage.
fine-tuning	A phrase meaning a highly constrained and implausible adjustment of the parameters of a theory.
trk	DSN Tracking System
asat	Anti-Satellite
polarisation	Restricting the vibrations of waves, particularly light, to move in one direction, along one plane.
cosine law	see Lambert's Law
ism	Interstellas medium.
nist	National Institute of Standards.
atomic number	The number (Z) of protons within the atomic nucleus
axion	A hypothetical spin-0 particle with a very small mass of 10-5-10-3 eV
tracking	Ground facilities employed to follow the progress and to communicate with a satellite.
semi-major axis	Half the distance of an ellipse's maximum diameter, the distance from the center of the ellipse to one end.
subduction	The descent of a slab of crustal rock into the interior of a planet where two tectonic plates converge.
exothermic fusion process	A fusion reaction which linerates energy.
lowell's band	A dark border sometimes found on the Martian polar cap.
bps	Bits Per Second, same as Baud rate.
density	The amount per unit volume
m	Mega, a multiplier, x106 (million) from the Greek "megas" (great)
natural gas	A mixture of methane and other gases, found trapped over petroleum deposits under the earth.
biconcave	Describing a lens with two concave faces
neutropenia	A low number of neutrophils or white blood cells (WBC's); may increase the risk of infection depending how low the wbc count is and for how long it has been low.
susceptibility	Symbol: X The ratio, for a given substance, of the magnetization of a sample to the magnetic field strength applied
optical fibre	Glass and transparent plastics can be made into a very thin wire or fiber
jpl	Jet Propulsion Laboratory, operating division of the California Institute of Technology.
photosynthesis	A complex process used by many plants and bacteria to build carbohydrates from carbon dioxide and water, using energy derived from light.
binning	On-chip binning
manufacturing	Process of creating equipment usually with machinery.
charge	The fundamental property of a particle that causes it to be affected by the electromagnetic force.
fourier component	A measure of the fluctuations of some physical quantity on a particular length scale
circle	An ellipse possessing but one focus.
turbulence	a hydrodynamic flow characterized by an irregular space and time dependence
celestial sphere	the visible, seemingly spherical surface that appears to surround Earth and to be centered at the observer
mass defect	(a) The mass equivalent of the binding energy of a nucleus
physics	the science of matter and energy and their interactions.; "his favorite subject was physics"
hypothesis	A tentative theory or supposition, advanced to explain certain or phenomena, which is subject to further tests and verification.
mass number	see Atomic Mass Number
orbital	A wavefunction that describes what an electron with a given energy is doing inside an atom or molecule.
almagest	Arabic title for Ptolemy of Alexandria's Syntaxis, the writings in which he combined his own astronomical researches with those of others
radiocarbon dating	Determination of the age of a substance containing radioactive carbon by means of its radioactive half-life
week	An arbitrary period of days, usually seven days; approximately equal to the number of days counted between the four phases of the Moon
pattern recognition	A computational technique used to find patterns and develop classification schemes for data in very large data sets.
dt	Design Tolerance
ultrasound / ultrasonography	A technique in which high-frequency sound waves bounce off internal organs and their echoes are changed into pictures of organs inside the body.
sa	Solar Array, photovoltaic panels onboard a spacecraft.
standard error	The standard deviation of a distribution of means or any other statistical measure computed from samples
solar constant	rate at which radiant solar energy is received normally per unit area at the outer layer of Earth's atmosphere; its value is about 1.94 gram calories/cm
frequency standard	A generator whose output is used as a precise frequency reference; a primary frequency standard is one whose frequency corresponds to the adopted definition of the second (see Second; Système International), with its specified accuracy achieved without calibration of the device
robot	A machine, often computer controlled, that is capable of performing complex tasks automatically.
hygroscopicity	The ability of a substance to absorb moisture from air
horizon distance	the maximum distance, at any given time, that a light signal could have travelled since the beginning of the Universe
genus	taxonomic category ranking below a family and above a species
reflection	The deflection or bouncing of electromagnetic waves when they encounter a surface.
primordial nucleosynthesis	The first time that nuclear atomic particles, neutrons and protons, could combine to make atomic nuclei
hematologist	A doctor who specializes in the treatment of blood diseases.
teratogen	A substance that can cause deformities in embryos
caltech	The California Institute of Technology.
non-hodgkin's lymphomas	A group of lymphomas characterized by cancerous growth of different types of lymphatic cells, excluding those characterized by Hodgkin's Disease
thermion	An ion, either positive or negative, which has been emitted by a heated body
pediatric	Relating to children, childhood.
thermal	Relating to heat or heat transfer.
magnetic force	One of the fundamental forces of Nature
em	Electromagnetic.
implicate order	A term coined by the physicist David Bohm to describe the sort of enfolded order that is characteristic of quantum theory
scattering	The process whereby light is absorbed and reemitted in all directions, with essentially no change in frequency
scale length	A measure of the size of a physical system or region of space
bubble	The false vacuum decays in a manner similar to the way water boils, forming bubbles of normal matter in the midst of the false vacuum, just as bubbles of steam form in the midst of water heated past its boiling point
ultraviolet light	Region of the electromagnetic spectrum spanning wavelengths from 91.2 nm to 350 nm, wavelengths largely blocked by the Earth's atmosphere.
thymus	An organ in which lymphocytes mature and multiply
exchange interaction	the spin-dependent part of the interaction between particles with spin
newton's law of motion	One of three laws describing the motion of bodies based on the conception of an absolute and immutable space and time; these laws held sway until Einstein's discovery of special relativity.
billion	one-thousand million, 10
rift zone	elongated valley formed by the depression of a block of Earth's crust between two faults or groups of faults of approximately parallel strike
attenuation	Process by which a compound is reduced in concentration over time, through adsorption, degradation, dilution, and/or transformation
geomagnetic activity	Natural variations in the geomagnetic field, classified qualitatively into quiet, unsettled, active, and geomagnetic storm levels based on the A index and the range of K indices observed.
pm	Picometer (10-12 m).
bus	The general term for hardware for dealing with the input-output pathway and backplane of a computer
taxon	group of organisms constituting one of the formal units in taxonomic classification (phylum, order, etc.) and characterized by common characteristics in varying degrees of distinction
k line	A Mg II resonance line at 2795.5 Å
central venous catheter	A special thin flexible tube placed in a large vein. It remains there for as long as it is needed to deliver or withdraw fluids.
cathode-ray tube	Basis of the TV tube and the oscilloscope
flux density	Flux of radiation through a unit surface; the strength of an electromagnetic wave, defined as the amount of power incident per unit area
malt / maltoma	Mucosa-Associated Lymphoid Tissue) - A low grade B-Cell non-hodgkin's lymphoma arising most commonly in the stomach, salivary gland, lung, or thyroid tissue. The gastrointestinal tract, particularly the stomach, is the most frequently involved site
qualification model	Satellite prototype used to confirm the design and performance of the final flight model.
analgesic	A pain-relieving drug
granulocyte-colony stimulating factor	A treatment agent used to stimulate the production of granulocytes in the bone marrow
g	Acceleration due to a body's gravity
sublimation	A direct change of state from solid to vapor without melting
gene pool	total amount of information in all the genes of all the reproductive members of a biological population at any given time
photoelectric effect	Ejection of electrons from an atom or molecule that has absorbed a photon of sufficient energy
klystron	A microwave travelling wave tube power amplifier used in transmitters.
torus	The two-dimensional surface of a doughnut.
antibody	A protein formed by the body to fight infections
aat	Anglo-Australian Telescope
aliasing	In a discrete Fourier transform, the overlapping of replicas of the basic transform, usually due to undersampling
main group elements	Elements of the s and p blocks.
veil nebula	see Cygnus Loop
convection	Transport of heat through movement of a gas or liquid.
hysteresis	(a) The ability to follow two different branches of states, as a parameter built in the system varies first in a monotonic fashion and subsequently comes back to its initial value by varying in the opposite direction
inferior planet	Planet which orbits closer to the Sun than the Earth's orbit.
opacity	The degree of obstruction to the transmission of visible light
sdc	System Design Complete
halley	The most famous periodic comet
hydrogen	simplest atom, consisting only of one proton and one electron; the most abundant element in the Universe
cpt invariance	A symmetry which is believed to hold true for all particles throughout the course of universal history
visual magnitude	The magnitude determined with the eye
string theory	Fundamental one-dimensional object that is the essential ingredient in string theory.
molar volume	The volume occupied by one mole of a material
do white dwarf	both He and H lines present
reset noise	The unwanted and uncertain electrical signal transmitted to the output pin of a CCD during the process of recharging, via the reset transistor, the output storage capacitor to its preset value in readiness for the next pixel charge
dissociative recombination	Capture of an electron by a positive molecular ion, wherein part of the recombination energy dissociates the molecule into two neutral atoms.
hyperbolic	Having the shape of a hyperbola, a particular form of curve whose two `arms' diverge and never rejoin.
specific impulse	A measurement of a rocket's relative performance
threshold energy	Difference between the energy at the first excited level and that of the ground state
lawrencium	A radioactive transuranic element of the actinoid series, not found naturally on Earth
sunspot cycle	Periodic variation in the number of sunspots which is related to changes in overall solar activity
surfactant	A material that spreads along a surface, changing the properties of the surface
supercooling	(a) The process by which a substance is cooled below the temperature at which a phase transition should occur, such as water that has been cooled to below zero degrees Centigrade but that has not yet formed ice
derived unit	Derived units are units constructed from the SI system's base units
glutamate receptors	Glutamate receptors are protein molecules that helps gate the flow of ions across a nerve cell's membrane
molecular geometry	1
visible	Pertaining to radiant energy in the electromagnetic spectral range visible to the normal human eye (approximately 380 to 780 nm.
sol	A colloid with solid particles suspended in a liquid
atomic mass number	The total number of protons and neutrons in an atom's nucleus
back focal length	The distance between the last surface of a compound optical system and the focal plane of the system
oceanic basalts	rocks of the oceanic island volcanoes
x-ray crystallography	Determination of three dimensional arrangement of atoms in a crystal by analysis of x-ray diffraction patterns.
density	The ratio between the mass of an object and its volume.
intramuscular	Into the muscle.
binary star	Pair of stars bound together by mutual gravitation and orbiting their common centre of mass.
microbe	(also microorganism) A microscopic single-celled living organism.
twilight	The interval of time preceding sunrise and following sunset (see Sunrise; unset) during which the sky is partially illuminated
epitaxial	growing on a crystalline substrate in such a way as to mimic the orientation of the substrate
wave	An oscillating motion that moves outward from the source of some disturbance (ripples running away from a pebble tossed in a pond)
franck-condon principle	A theoretical interpretation of the relative intensity of vibrational transitions in an electronic band on the assumption that the intense transitions correspond to situations where an endpoint in the lower vibrational level is vertically below the corresponding endpoint in the upper vibrational level
theta pinch	A fusion device in which the magnetic field runs parallel to the plasma column
solubilizing group	A group or substructure on a molecule that increases the molecule's solubility
ac	Alternating current.
ensemble average	An average over an ensemble of all possible systems
feynman diagram	(a) Schematic representation of an interaction between particles
valence electron	Electrons that can be actively involved in chemical change; usually electrons in the shell with the highest value of n
transverse waves	Waves vibrating at right angles to the direction of propagation - e.g., electromagnetic waves
cytomegalovirus	A type of virus that can cause unapparent infections in healthy individuals but is dangerous to immunosuppressed patients
orionis	Betelgeuse
bacterium	any of an extremely flexible class of microscopic plants whose members have a variety of structures, come singly or in colonies, live just about anywhere, and derive energy from whatever source is available
biological therapy	Treatment with substances that can stimulate the body's immune system to fight disease more effectively
micron	Unit to measure length
x-band	A range of microwave radio frequencies in the neighborhood of 8 to 12 GHz.
royal society	English organization founded in the seventeenth century and dedicated to the advancement of science
w virginis stars	Population II Cepheids
metal-rich	Having a high metallicity with respect to olar
filament	A prominence seen in projection on the solar disk.
lymphocytes	A type of white blood cell that fights infection and disease and is found in the bloodstream, the lymphatic system, and lymphoid organs
micron	10
hygroscopically	By absorbing moisture from air.
two-way	Communications mode consisting of downlink received from a spacecraft while uplink is being received at the spacecraft
lna	Low-noise amplifier in DSN, either a maser or a HEMT.
nucleic acids	long, chainlike molecules which, in the various combinations of constituent groups, embody the genetic code (DNA) and assist with its transmission (RNA)
centripetal acceleration	The inward acceleration of a body revolving around another body.
ethernet	A system for linking computers with a single serial cable
electromagnetic spectrum	The complete array of electromagnetic radiation (light)
atomic mass unit	(a) A unit of mass used for atoms and molecules, equal to 1/12 of the mass of an atom of carbon-12
leukopenia	A low number of leukocytes or wbc's
almanac	A book or table listing astronomical events.
rayleigh	(a) Unit of flux
instrument	Apparatus capable of registering information with a precise objective
atomic number	Number of protons in the nucleus; commonly abbreviated as Z.
vincristine	A chemotherapy drug sometimes used to treat Non-Hodgkin's Lymphoma
regolith	The layer of fragmentary debris produced by meteoritic impact on the surface of the Moon or a planet
s/v	Space Vehicle
thermal energy	Energy associated with the motions of the molecules in a substance.
disk	The central plane of a spiral galaxy, as distinguished from the halo or the nucleus.
hertz	A measure of frequency
field	(a) A physical quantity, like the electric or magnetic field, which varies from point to point in space
radiation pressure	The transfer of momentum by electromagnetic radiation incident on a surface: prad = (4/3)T4 / c
orbital velocity	Velocity required by a body to achieve a circular orbit around its primary: Vorb = (GM / r)1/2
x-ray flare class	Ranking of a flare based on its x-ray output
white blood cell	A variety of cells that fight infection in the body and are part of the immune system.
distillate	The vapor collected and condensed from a distillation.
apogee	The point at which a body in orbit around the Earth reaches its farthest distance from the Earth
oblique rotator	A stellar model in which the rotational and magnetic axes are not coincident
boiling	Conversion of liquid into gas as bubbles of gas that form within the liquid
neurologic	Involving the nerves or nervous system.
uv	Ultraviolet (meaning "above violet") radiation
anti-ferromagnetism	A kind of magnetism found in many solids at low temperatures
linac	Linear Accelerator
coronal mass ejection	An outward eruption of billions of tonnes of material thrown into space from the Sun's corona
-process	A hypothetical process of nucleosynthesis (now considered obsolete terminology), which consisted of redistributing -particles in the region from 20Ne to 56Fe (and perhaps slightly higher)
vacuum	(a) A space containing gas below atmospheric pressure
sedr	Supplementary Experiment Data Record.
gallium scan	The patient is injected with radioactive gallium and scanned with a detection machine 2-5 days later. The gallium moves towards sources of inflammation/infection. Detailed information.
dsms	Deep Space Mission System, the system of computers, software, networks, and procedures that processes data from the DSN at JPL.
filament	A prominence seen in projection on the Solar disk
4	Trajectories 5 -- Planetary Orbits 6 -- Electromagnetics
mycosis fungoides	A type of non-Hodgkin's lymphoma that first appears on the skin
nucleation	The process of providing sites for 1) new bubbles to form in a liquid that is boiling or supersaturated with gas; 2) new droplets to condense from a supersaturated vapor, or 3) new crystals to form in a supersaturated solution
phenolpthalein	A common misspelling of phenolphthalein.
rem	The special unit of ? of the qualities expressed as dose equivalent
vacancy	A site on a lattice on which there is no atom present
pmpcb	Parts, Materials, Processing Control Board
hydrocarbon	A chemical compound containing only hydrogen and carbon atoms.
collagen	insoluble fibrous protein used by vertebrates to hold themselves together (i.e., it is a chief constituent of connective tissue fibrils and occurs in bones)
natural object	an object occurring naturally, not constructed by humans
tidal force	The differential gravitational pull exerted on any extended body in the gravitational field of another body
microchannel plate	A compact electrostatic high-voltage electron multiplier with a very large number of narrow pores or channels
salifiable	Capable of reacting with an acid to form a salt
density	The amount of matter in a prescribed volume of material.
kelvin timescale	The time it takes a star to contract gravitationally from infinite radius down to its present radius by radiating its thermal energy (for the Sun, about 2-3 × 107 years)
bin	output signal channel in a multichannel spectrum analyzer or MCSA (q.v.)
health physics	The science of protecting human beings from injury by radiation, and promoting better health through beneficial applications or radiation
iau	International Astronomical Union
dead person	a person that has died
bond order	1
cosmonautics	astronautics.
diurnal motion	The apparent daily motion of celestial bodies across the sky from east to west, caused by the Earth's rotation.
intralesional	into the cancerous area in the skin.
vgr2	Voyager 2 spacecraft.
focal spot	A small area on the target of the anode toward which the electrons from the focusing cup of the cathode are directed
chapman's equation	An equation expressing the velocity of a gas in terms of certain molecular constants
charles's law	The pressure of an ideal gas at constant volume varies directly as the absolute temperature
space weather	The changing conditions in interplanetary space caused by fluctuations in the solar wind.
open string	A type of string with two free ends
deep sea vent	Seafloor vent that releases hot, mineral-rich water from fissures at a mid-ocean ridge
image spectrometers	Refers to a class of instruments which preserve the image field while also determining the spectrum
module	Part of a satellite that has been designed and built and often tested as an entity.
lifetime	The time it takes for a sample of identical particles to decay to 1/e of its initial population (e 2.718)
titrant	The substance that quantitatively reacts with the analyte in a titration
carina ob 2	A rich association of OB stars near Carinae
first point of aries	see Vernal Equinox
reciprocal	The inverse of a number; for example, the reciprocal of 3 is 1/3, the reciprocal of 1/2 is 2
space-time continuum	(a) A four-dimensional framework in which events take place
organic chemistry	The study of compounds that contain carbon chemically bound to hydrogen, including synthesis, identification, modelling, and reactions of those compounds.
abstraction	a general concept formed by extracting common features from specific examples
stoichiometry	1
genetic drift	random fluctuations (or "walk") of gene frequencies from generation to generation that occur in small populations
leukemia	A blood disease which is characterized by overproduction of white blood cells
lon/lonization chamber	An x-ray measuring device in which gas is ionized in proportion to the quality of x-ray energy passing through the chamber.
fg sagittae	A supergiant whose spectral type has changed from B4 Ia in 1955 to A5 Ia in 1967 to F6 Ia in 1972
bond strength	Some measure of how difficult it is to break a chemical bond, for example, a bond energy or a bond enthalpy.
nucleotide	compound composed of a nucleoside combined with phosphoric acid
conservation of matter	The principle that matter is neither created nor destroyed
latent heat	Heat that is absorbed without causing a rise in temperature
metastasis	Spread of cancer cells from the original site to other parts of the body.
kardashev cultures	N
butanol	An alcohol containing four carbon atoms
s	Second, the SI base unit of time (see this extensive definition).
bremsstrahlung	The German word 'Bremsstrahlung' means 'braking radiation'
erythema	Redness of the skin.
oblateness	Ratio of the difference between the equatorial and polar radii to the equatorial radius
equation of state	(a) A relation between the pressure, temperature, and density of a fluid
decay constant	for an atom that undergoes radioactive decay, the decay constant is the proportionality factor between the time rate of decay and the total number of atoms present; it is the inverse of the mean lifetime of an atom
active site	A pocket or crevice on an enzyme molecule that fits reactant molecules like a hand in a glove
fermilab	The Fermi National Accelerator Laboratory, in Batavia, Illinois, USA
sss	Spin Sun Sensor
let	Linear Energy Transfer
electromagnetic spectrum	The electromagnetic spectrum is the complete range of wavelengths of the electromagnetic radiation.
granulocyte/macrophage-colony stimulating factor	A treatment agent used to stimulate the production of macrophages, granulocytes, and eosinophils in the bone marrow
hyad	A single member of the Hyades
m	Meter (U.S
hodgkin's disease	A malignant disorder of lymph tissue (lymphoma) that occurs mostly in individuals between the ages of 15 and 35
snr	Signal-to-Noise Ratio.
particulate	Composed of distinct particles
rich clusters	Clusters with a particularly large number of galaxies
cutaneous t-cell lymphoma	A type of non-Hodgkin's lymphoma that first appears on the skin
low grade	Low grade is associated with indolent, or slow growing cancers. NHL types that are low grade (indolent) are small lymphocytic, small cleaved cell follicular, mixed follicular, small cleaved cell diffuse, intermediately differentiated diffuse and cutaneous T-cell (mycosis fungoides).
mass	The total amount of material in a body, a measure of the amount of matter
cohomology	A branch of mathematics concerned with the patching together of spaces
aos	Acquisition Of Signal, used in DSN operations.
kepler's law of planetary motion	(astronomy) one of three empirical laws of planetary motion stated by Johannes Kepler.
pdc	Preliminary Design Complete
spleen	An organ that produces lymphocytes, filters the blood, stores blood cells, and destroys those that are aging
keyhole nebula	An old name for Eta Carinae
dose rate	Absorbed dose (or dose equivalent) delivered per unit of time.
kg	Kilogram
bound-bound transition	Transition between energy levels of an electron bound to a nucleus (the electron is bound both before and after the transition).
gdscc	DSN's Goldstone Deep Space Communications Complex in California.
pm	Post meridiem (Latin: after midday), afternoon.
eot	End Of Track, used in DSN operations.
mitochondrion	cytoplasmic organelle serving as a site of respiration
flat space	A synonym for ordinary Euclidean space
nuclear binding energy	Energy needed to break an atomic nucleus into separate protons and neutrons.
taste alteration	Temporary change in taste that may be a side effect of chemotherapy, cancer, or radiation.
super radiance	A process by which energy may be extracted from a rotating black hole
cloud chamber	A glass-walled enclosure containing a vapor in which particles can be detected by photographing the tracks of water droplets they leave behind when they pass through the chamber
protist	any of a kingdom of living organisms (Protista) that includes algae slime molds, protozoa, and fungi, usually characterized by unicellular reproductive structures, true nuclei, and chromosomes
baryons	The class of subatomic particles in which protons and neutrons are included
ossa	Office Of Space Science and Applications, NASA (Obsolete, see OSS).
canonical change	A periodic change in one of the components of an orbit (cf
mass motion	A non-uniform matter flow
emp	Electromagnetic Pulse
spectral lines	(a) Dark lines visible in an absorption spectrum, or bright lines that make up an emission spectrum
cmd	DSN Command System
f-type	Having a spectral type of F, that is, yellow-white, like Canopus and Procyon
reed-sternberg cell	A type of cell that appears in patients with Hodgkin's disease.
stokes	1 St = 1 cm2 s-1
white noise	Completely random and uncorrelated noise, with equal power at all frequencies
integrated circuit	A small electronic component made of semiconductor silicon on which an entire electronic circuit of numerous microscopic transistor amplifiers, diodes and resistors has been constructed
infusion	Administration of fluids or medications into the blood through the veins.
parallels	Circles in parallel planes to that of the equator defining north-south measurements, also called lines of latitude.
scaling	(a) The phenomenon observed in deep inelastic scattering, and predicted by James Bjorken, whereby the structure functions which describe the shape of the nucleon depend not on the energy or momentum involved in the reaction, but on some dimensionless ratio of the two
remission	The complete disappearance of cancer cells and symptoms
computational chemistry	A branch of chemistry concerned with the prediction or simulation of chemical properties, structures, or processes using numerical techniques.
parallax	The apparent motion of a relatively close object compared to a more distant background as the location of the observer changes
intermolecular force	An attraction or repulsion between molecules
radioactivity	Spontaneous decay of atomic nuclei
radian	(a) A measure of angular distance; 2 radians equals 360 degrees
resolution binwidth	equivalent power bandwidth, ; if p
elv	Expendable launch vehicle.
corrector plates	Thin lens-like optical pieces which remove certain optical aberrations
enkephalin	Enkephalins are molecules produced naturally by the central nervous system to numb pain
b-factory	A b-factory is a facility designed to produce and detect large numbers of b-quarks, at least 100 million a year
perfect crystal	A crystal with no defects or impurities, made of completely identical repeating subunits
ert	Earth-received time, UTC of an event at DSN receive-time, equal to SCET plus OWLT.
absorption coefficient	Fraction of the incident radiation absorbed at a certain wavelength per unit thickness of the absorber
beacon	Downlink from a spacecraft that immediately indicates the state of the spacecraft as being one of several possible states by virtue of the presence and/or frequency of the subcarrier
quantity	A term used to describe the number of photons in an x-ray beam.
marginal zone lymphoma	A term used to encompass indolent B-Cell lymphomas that are either MALT or monocytoid B-Cell lymphoma
molecules	The smallest units of a chemical compound
optical pair	A pair of stars that appear close together on the sky as a result of perspective only, and that have no physical relation
hyperalimentation	Nutritional support given through a vein.
vela x	A compact radio source about 400-500 pc distant associated with the Vela supernova remnant
pathfinder	The Mars Environmental Survey (MESUR) engineering prototype later named Mars Pathfinder.
atom	The smallest unit of matter that retains the properties of a chemical element
pll	Phase-lock-loop circuitry in telecommunications technology.
mole fraction	Concentration of a substance in a mixture measured as moles of the substance per mole of mixture
adriamycin	A chemotherapy drug (generic name doxorubicin) commonly used to treat Hodgkin's disease and other forms of lymphoma
fourier theorem	Any finite periodic motion may be analyzed into components, each of which is a simple harmonic motion of definite and determinable amplitude and phase
compact infrared sources	Strong compact infrared sources embedded in nebulosity
fractal	(a) A geometric figure in which a pattern is repeated ad infinitum on smaller and smaller scales
ram	Random access memory
ozone layer	layer of Earth's atmosphere at about 20 to 30 miles, marked by a high ozone (0
subcarrier	Modulation applied to a carrier which is itself modulated with information-carrying variations.
latch	Mechanical device that attaches one component, such as a science instrument, to the structure of the telescope and holds it in precisely the right place.
m87	A giant elliptical galaxy in the Virgo cluster
local bubble	The region of the Galaxy near the Sun which has little neutral hydrogen gas.
kepler's supernova	A Type I supernova (SN Oph 1604) whose light reached Earth in 1604
virtual particle theory	Theory devised by Stephen Hawking to account for apparent thermal radiation from a black hole (from which not even light can escape)
lens	Transparent optical element or assembly with either a concave or convex surface, which refracts light to form an image.
facula	(1) Bright region of the Sun's photosphere
group	1
spall	Dynamic fracture of a material resulting from a very short duration stress pulse.
lga	Low-Gain Antenna onboard a spacecraft.
three-phase	A CCD construction in which three overlapping metal electrodes are used to define a pixel and effect the transfer of charge, in either direction along a column, by the charge-coupling method
leukocyte	A white blood cell (wbc). There are 3 main types of leukocytes: monocytes, granulocytes, and lymphocytes.
watt	The SI unit of power
grade	The speed at which a type of Non-Hodgkin's develops
white blood cell count	Measurement of the total number of white blood cells in a sample of blood
sculptor	1
intra-arterial	Into an artery.
co2	see Carbon Dioxide
replication	Process by which multiple copies of an original element are reproduced, all with identical characteristics.
vlasov-maxwell equations	Equations that describe the propagation of radiation in hot, collisionless plasmas
replacement current	The photoejection from and transfer of charge in a system creates a charge imbalance
central nervous system	The control center for the body - includes the brain and spinal cord.
science	The attempt to find order in nature or to find laws that describe natural phenomena.
smart-1 mission	The first of the European Space Agency's `Small Missions for Advanced Research in Technology'
neutron star	A dead, collapsed star that consists mostly of neutrons and is only about 20 kilometers across
ablation	Erosion of an object (generally a meteorite) by the friction generated when it passes through the Earth's atmosphere
symmetry	(a) A property of a physical system that does not change when the system is transformed in some manner
grotrian diagram	Energy-level diagram
gmt	Greenwich Mean Time
hydrocarbons	A group of chemical compounds composed only of carbon and hydrogen.
yellow spot	An area a few millimeters across in the human retina
rise	As in ascending above the horizon, for the technical definition, please follow this link to the U.S
unimolecular reaction	A reaction that involves isomerization or decomposition of a single molecule.
interstellar cloud	A collection of gas and dust that lies between the stars
angstrom	A unit of length equal to 1E-8 centimeters.
a ring	The outermost of the three rings of Saturn that are easily seen in a small telescope.
su	mathematical structure known as a `group' that describes operations on N objects
chance	Characteristic of a regime in which predictions cannot be made exactly, but only in terms of probabilities
z	Zetta, a multiplier, x1021 from the last letter of the Latin alphabet
thermochemical equation	An compact equation representing a chemical reaction that describes both the stoichiometry and the energetics of the reaction
ne	Near Encounter phase in flyby mission operations.
centigray	0.01 Gray (Gy)
zetta-	Symbol: Z A prefix denoting 1021
wheatstone bridge	A device that measures the resistance of an electrical circuit to the flow of electricity
esa	European Space Agency.
kilogram	A unit of mass
sos	Silicon on Sapphire
rankine scale	A temperature scale with the same division as the Fahrenheit scale and the zero point at 0° absolute
forbush decrease	A decrease in cosmic-ray intensity with an increase in olar activity (and vice versa)
total body irradiation	Radiation aimed at the entire body to destroy cancer cells
time	A dimension distinguishing past, present, and future
power	The rate at which energy is supplied
rare earth elements	series of elements usually taken to include elements with atomic numbers 58 to 71, lanthanum, and sometimes yttrium and scandium
weinberg angle	parameter in the electroweak theory
survey	Means an evaluation of the radiation hazards incident to the production, use, release, disposal, or presence of sources of radiation.
cation	A positively charged ion, formed by removal of electrons from atoms or molecules
degassing	process whereby the atmosphere and ocean water have slowly accumulated through geologic time by emanating from Earth's interior in the form of volcanic gases
biosphere	The part of a planet or moon (its atmosphere, waters, soil, and crustal rock) in which living organisms exist.
transverse wave	A wave motion in which the motion or change is perpendicular to the direction of energy transfer
bi-phase	A modulation scheme in which data symbols are represented by a shift from one phase to another
emr	Electromagnetic radiation.
irradiance	Symbol: E The rate of energy reaching unit area of a surface; i.e
dtt	The DSN Downlink Tracking & Telemetry subsystem.
lumbar puncture	Also called a spinal tap - involves the removal of the fluid in the spine for examination. Can cause headache afterwards.
thermistor	A device that senses temperature changes by using a resistor with an electrical resistance that falls when temperature rises.
internet	A global spider-web-like network of computers and computer systems with no central hub or single point of control
tropopause	Upper boundary of the troposphere (about 15 km), where the temperature gradient goes to zero
zone refining	A method for purifying solids based on the fact that solutes tend to concentrate in the liquid when a solution is frozen
chemosynthesis	synthesis of organic compounds using energy derived from chemical reactions
anisotropy	(a) A medium is anisotropic if a certain physical quantity differs in value in
uhuru	A satellite devoted entirely to the study of cosmic X-ray sources
zodiacal constellation	a constellation within the Zodiac region, each is a sign of the zodiac except for Ophiuchus
endothermic process	An adjective applied to a reaction in which a net input of energy is required for the reaction to occur
immunosuppressant	A or other factor that prevents the immune system from reacting to foreign substances and fighting disease.
e	East.
pi	Principal Investigator, scientist in charge of an experiment.
standstill	An interval in the cycle of a variable star during which the brightness temporarily stops changing
winding energy	The energy embodied by a string wound around a circular dimension of space
exoergic process	A process in which energy is liberated
cit	Current Injection Test
reconnection	The rejoining of magnetic lines of force severed by the annihilation of the field across the neutral region
meteor	A bright streak of light produced by a small fragment of rock or metal that burns up as it enters the atmosphere.
hcp	Hardness Critical Process/Procedure
iris	An arrangement able to vary the amount of light that enters an optical instrument
dose rate	The dose absorbed per unit time.
meter	(a) The SI unit of length
mhz	Megahertz (106 Hz).
gonard shielding	Devices used during radiographic procedures to protect the reproductive organs from exposure to the useful x-ray beams.
aggressive lymphoma	A fast growing lymphoma. It is also known as high-grade lymphoma. These lymphomas respond well to chemotherapy and radiation treatments. More on Aggressive Lymphoma
triple point	The only point at which the gas, solid, and liquid phases of a substance can coexist in equilibrium
electron volt	Energy required to move an electron through a potential difference of 1 volt
thermal energy	Energy associated with the motions of the molecules, atoms, or ions in a substance
d	Total dose in rad(Si)
kelvin	(a) The temperature scale that astronomers usually use
kl nebula	See Kleinmann-Low nebula
faculae	(a) Bright areas on the face of the Sun, commonly in the vicinity of sunspots
grating	See diffraction grating
viscosity	The internal friction of a fluid or liquid that tends to resist and dissipate its flow
phase delay	signal travel time between two points in any signal path or circuit (measured in seconds or in degrees or radians of the signal frequency); to be distinguished from simultaneous phase difference between two points
precipitation	Precipitation is the conversion of a dissolved substance into insoluble form by chemical or physical means.
convergent	Coming together
useful beam	Means that part of the radiation which passes through the window, aperture, cone, or other collimating device of the tube housing.
zymase	Enzymes present in yeast that catalyze fermentation of sugar into alcohol and carbon dioxide.
cluster	1
objective	(a) The lens or combination of lenses nearest the object in an optical instrument
harvesting	removing tissue or cells from a donor and preserving them for transplantation
universal attraction	see Law of Universal Attraction
secondary electron	An electron emitted as a result of bombardment of a material with radiation.
complementary therapy	Techniques or approaches often used in addition to standard treatment
charge conjugation	The technical term for mathematical operations which interchange particles and antiparticles
cnes	Centre National d'Études Spatiales, France.
brillouin scattering	Slight changes in the frequency of radiation, caused by reflection or scattering from the high-frequency sound waves that arise from thermal vibrations of atoms in the medium
voids	Large regions of space without galaxies
sinusoidal grating	The grating groove profile is sinusoidal.
hertz	(Hz) A unit of frequency equal to one cycle (or wave) per second
coded mask	Mask made for example of lead, tungsten, aluminium, etc
magnitude	relative measure of the brightness of celestial objects
beehive cluster	See Praesepe
tpd	Terminal Protection Device
mills cross	An antenna array consisting of two antennas oriented at right angles to each other
diatomic molecule	a molecule containing only two atoms which can be of different elements
polymer	A large molecule made by linking smaller molecules ("monomers") together.
meteor	A meteoroid which is in the process of entering Earth's atmosphere
alt	Altitude.
ccd	Charge Coupled Device, a solid-state imaging detector.
rayleigh number	(a) A non-dimensional parameter involving the coefficients of thermal conductivity and kinematic viscosity which determines when a fluid, under specified geometrical conditions, will become convectively unstable
mean life	The mean time before decay of a large number of similar particles
w	West.
element	A substance composed of atoms having the same number of protons in each nucleus.
acidulant	A substance added to food or beverages to lower pH and to impart a tart, acid taste
chromosome	A strand of DNA and related proteins that carries the genes and transmits hereditary information.
sef	Spacecraft event file.
aspect ratio	Ratio of the major axis (e.g., of a rocket) to the minor axis
titration	A procedure for determining the amount of some unknown substance (the analyte) by quantitative reaction with a measured volume of a solution of precisely known concentration (the titrant).
galilean transformation	The non-relativistic method of relating observations from one frame of reference to another.
quanta	(a) Fundamental units of energy
pyrimidine	nitrogen base such as cytosine, thymine, or uracil that is a constituent of nucleotides and nucleic acids
qab	Quality Assurance Board
carbohydrate	organic compound consisting of a chain of carbon atoms to which hydrogen and oxygen, present in a 2:1 ratio, are attached
acid-base indicator	A weak acid that has acid and base forms with sharply different colors
collinear	Three or more points lying in a straight line
crust	The solid surface layer of a planet or moon
dacarbazine	A chemotherapy drug commonly used to treat Hodgkin's disease
invisible astronomy	The study of celestial objects by observing their radiation at wavelengths other than those of visible light
extraterrestrial	Located or originating outside the Earth and its atmosphere.
quadrupole	When referred to a system containing charges, a quadrupole is equivalent to the presence of two equal dipoles parallel to each other, but with their corresponding charges reversed; or more generally, that component of the charge distribution which has axial or triaxial symmetry
critical path	A term used in project planning to indicated a segment of the proposed work which if not completed on time will result in one or more other segments being delayed with serious "knock-on" effects for the project
moment of inertia	The product of the mass of a body and the square of its radius of gyration
abundance	Relative number of atoms of a particular element, or isotope of an element, in the chemical composition of a single substance or object.
sub-atomic	Of a scale smaller than that of an atom
cartesian	One who follows the philosophy of René Descartes regarding his logical analysis or interpretation of nature.
climatology	The study of climate - the prevailing atmospheric conditions of humidity, temperature, winds etc.
lagrange points	Five points with respect to an orbit which a body can stably occupy
fundamental stars	Stars for which coordinates have been determined to a very high degree of accuracy
coordinate transformation	Method of relating observations from one frame of reference to another.
icrf	International Celestial Reference Frame
high grade	A grade of Non-Hodgkin lymphoma denoting fast growth.
well-differentiated lymphocytic lymphoma	Old Rappaport classification for the form of Non-Hodgkin's Lymphoma now known as small lymphocytic lymphoma.
fdc	Final Design Complete
tessera	unit of a mosaic
gauge group	the mathematical group associated with a particular set of gauge transformations
boundary layer	A thin layer of fluid, such as the one next to a solid surface past which the fluid is moving
tesla	The derived SI unit of magnetic flux density
somatic	Retaining to the body tissue other than reproductive cells.
fov	Field of View
dc	The DSN Downlink Channel, several of which are in each DSN Downlink Tracking & Telemetry subsystem, DTT.
pst	Pacific Standard Time.
tempon	A unit of time equal to the length of time it takes light to cross the classical radius of an electron (about 10-23) seconds)
quantum tunneling	A quantum leap through a barrier
gut	Grand Unified Theory
beta-particle	Particles first discovered in radioactive β decay - later identified as electrons.
polymerization	A process that links smaller molecules together to form a larger molecule.
fried parameter	A measure of the scale of the turbulence in the atmosphere
recession	Motion (increasing distance) away.
ultraviolet radiation	Electromagnetic radiation "beyond the violet" with wavelengths in the approximate range 100-4000 Å
molar mass	The mass of one mole of a material
rutherfordium	A radioactive metal not found naturally on earth
overshoot	A condition that obtains when the momentum of a particle carries it past its equilibrium point
fuel cell	A device that converts the chemical energy obtained from a redox reaction directly into electrical energy.
millimeter	10-3 meter.
hla	see Human Leukocyte Antigen
fireball	see Meteor; see also Primeval Fireball
vernal equinox	(a) The spring equinox, on or around 21 March
cone	A round/circular metal tube/shield attached to the x-ray tube housing or placed in front of the x-ray tube to limit the size of the x-ray beam to a predetermined size and shape.
era	A system of chronological notation reckoned from a given date
splenectomy	Surgical removal of the spleen
star streaming	A phenomenon that arises because the mean random speeds of the stars are different in different directions
orbit	The path in space followed by a celestial body
watch and wait	A period of using no treatment or little treatment and seeing how the lymphoma progresses
open cluster	(a) A small, loose cluster of stars that typically contains several hundred members
flickering	Aperiodic behavior in an oscillating system; rapid, large-amplitude variations in light
j-file	A group of lines of a supermultiplet having a common lower level
velocity profiles	In radio astronomy, the output response for all filters for a given position of the beam on the source
si base unit	One of seven SI units of measure from which all the other SI units are derived
kilometer per second	The unit of speed in astronomy
wave	A propagating pattern of disturbance
non-coherent	Communications mode wherein a spacecraft generates its downlink frequency independent of any uplink frequency.
nm	Nanometer (10-9 m).
free radical	A free radical is a molecule with an odd number of electrons
neoteny	attainment of sexual maturity during the larval stage
optical light	The region of the electromagnetic spectrum with wavelengths in the range of 4 x 10-7 meters to 7 x 10-7 meters
organic molecules	Molecules formed by chemical bonds mainly between carbon atoms
oosterhoff groups	Two groups of globular clusters which differ in the period of transition between Bailey type ab and type c variables, the ratio of type c to type ab stars, in the metallicity of RR Lyrae stars, and in the mean period of the ab variables
radio	The region of the electromagnetic spectrum with wavelengths longer than 10-4 meters
neutron	An electrically neutral subatomic particle found in the nucleus of all atoms except ordinary hydrogen.
stability	A measure of how hard it is to displace an object or system from equilibrium
solid-state	Usually implies crystalline semiconductor materials used in the electronics industry
zeeman effect	(a) The splitting of atomic spectral lines into two or more components in a transverse magnetic field
tool	material object used to make other objects or to facilitate activities such as resource extraction
ftp	File Transfer Protocol
escape velocity	The minimum speed needed to escape the gravitational attraction of a celestial body and enter space
trm	Transmission Time, UTC Earth time of uplink.
filter/filtration	Means material placed in the primary or useful x-ray beam to absorb preferentially the less penetrating radiations
meter	The fundamental SI unit of length, defined as the length of the path traveled by light in vacuum during a period of 1/299,792,458 s
electron	A small, negatively charged particle that appears in every neutral atom, surrounding the positively charged nucleus like bees around honey.
cdu	Command Detector Unit onboard a spacecraft.
vapor pressure	The pressure exerted at a particular temperature by a vapor
salt bridge	A tube (often filled with ion-laced agar) that allows two solutions to be in electrical contact without mixing in an electrochemical cell.
absorption	Decrease in intensity of radiation, when it crosses a material medium, as a consequence of an interaction between the radiation and the material medium.
unitarity	The principle of conservation of probability
order	An integer (m) associated with a given interference fringe or diffraction pattern
rad	The unit of absorbed dose.
selenology	the branch of astronomy that studies the moon.
igneous rock	Rock that has crystallised from a molten state (magma).
space	Traditionally the three-dimensional theater within which events transpire, explicable by means of Euclidean geometry
jitter	Irregular random variations in a radio signal
lymphomatoid granulomatosis	A B-cell lymphoma that is now called pulmonary angiocentric B-cell lymphoma.
anharmonic oscillator	A system whose vibration, while still periodic, cannot be described in terms of simple harmonic motions (i.e
empathy	Understanding another person's feelings by remembering or imagining being in a similar situation.
device	an instrumentality invented for a particular purpose
am	Ante meridiem (Latin: before midday), morning.
gray body	A body whose emissivity is constant and less than unity
terminal	1
curie	Unit of measuring radioactivity
otm	Orbit Trim Maneuver, spacecraft propulsive maneuver.
ki-1 lymphoma	The old classification of an Anaplastic Large Cell Lymphoma (ALCL).
inorganic chemistry	The study of inorganic compounds, specifically their structure, reactions, catalysis, and mechanism of action.
needle biopsy	A sample of tissue is taken with a needle and looked at under a microscope.
zero point energy	A minimum possible energy for an atom or molecule predicted by quantum mechanics
luminous	Intrinsically bright, as opposed to being just apparently bright
wave mechanics	A quantum-mechanical theory introduced by Schrödinger in 1926 which ascribes wave characteristics to the fundamental entities of atomic structure, and formulates the appropriate wave equation (Schrödinger's equation)
binwidth	nominal frequency bandwidth of a bin; see
wavelength	The distance between two peaks of a wave
recurrence	The return of cancer after a period of being diagnosed cancer free (in remission).
back warming	Heating of deeper layers in a star due to overlying opacity
axillary lymph node	A lymph node found in the underarm region (axilla).
soyuz rocket	Russian rocket which has been launched 1500 times since 1963
decibel	dB, an expression of ratio (see dB, above)
fokker-planck equation	A modified form of the Boltzmann equation allowing for collision terms in an approximate way
polypeptide	molecular chain of amino acids
precession	A slow, periodic conical motion of the rotation axis of a spinning body
dynamics	The physics that explains how particles and systems move under the influence of forces
mural arc	Sixteenth- to nineteenth-century astronomical apparatus comprising a carefully oriented wall on which a calibrated device was fixed, by which the altitudes of celestial objects could be measured
binding energy	The binding energy of a nucleus is the minimum energy required to disassociate it into its component neutrons and protons
w3	A dense cloud of gas about 3 kpc distant in the Perseus arm
laminar flow	Steady flow in which the fluid moves past a surface in parallel layers of different velocities
stimulated emission	(a) Radiation emitted by a body, such as an atom, when it is bombarded by radiation
radioactive particle	A particle which can produce harmful radioactivity directly through its decay or by interacting with other particles.
ipt	Integrated Product Team
kurtosis	The peakedness or flatness in the graphical representation of a statistical distribution
concave	Curved inwards (as opposed to convex), as in certain mirrors.
collimate	To make parallel, neither diverging nor converging
probe	An unmanned vehicle travelling into space to celestial bodies in order to collect information about them.
txr	DSN's DSCC Transmitter assembly.
integral mission	International Gamma-Ray Astrophysics Laboratory
array	In radio astronomy, an arrangement of antenna elements designed to produce a particular antenna pattern
thermodynamics laws	The first is the law of conservation of energy; the second is the law of entropy
vector space	A set of elements (called Vectors) for which a binary operation of vector addition is defined, such that u1 + u2 is a vector if u1 and u2 are vectors: and a binary operation scalar multiplication is defined, such that cu is a vector if u is a vector and c is a scalar (a real number or a complex number, according to specification of the kind of vector space); and a standard collection of conditions governing these two operations is satisfied
red blood cell	Blood cell that carries oxygen to the cells of the body and removes carbon dioxide.
lymphomatoid papulosis	A rare skin disorder that appears to be cancer but is actually benign in most cases. More Information.
cetus arc	A gaseous nebula, probably about 100 pc distant, centered on or near Peg
reflector	A telescope that uses a mirror - instead of a lens - to collect and focus the light coming from astronomical objects
19th century scientist	a scientist born between 1800 and 1900 AD
transition metal	One of the metals such as iron, manganese or platinum in the centre of the periodic table
elastic collision	Particle reactions in which the same particles emerge from the reaction as entered it (e.g
kaolinite	mineral (a hydrous silicate of aluminum) that constitutes a principal part of the fine clay, kaolin
optical depth	A measure of the integrated opacity along a path through a layer of material, measured by the amount of absorption of a beam of incident light
spc	Signal Processing Center at each DSCC.
polynucleotide	polymeric chain of nucleotides
density	The mean density of a celestial body is generally reckoned as its mass divided by its volume, expressed either in comparison with the density of water, in kilograms per cubic meter, or in relation to some other known density
standard molar volume	The volume of 1 mole of an ideal gas at STP, equal to 22.414 liters.
tritium	A radioisotope of hydrogen with two neutrons and one proton in its nucleus.
phase transition	An abrupt change in the equilibrium state of a system
edl	(Atmospheric) Entry, Descent, and Landing.
thermal equilibrium	(a) A state in which there is no net flow of heat
electrorefining	Electrorefining is a method for purifying a metal using electrolysis
tokamak	A type of "magnetic bottle" used in experiments on controlled nuclear fusion
thermometer	An instrument for measuring temperature.
protective barrier	Barrier of attenuating materials used to reduce radiation exposure.
opct	Operations Planning and Control Team at JPL, "OPSCON." Obsolete, replaced by DSOT, Data Systems Operations Team.
prominence	Large cloud of plasma extending above the Sun's chromosphere
ganymede	The largest of Jupiter's moons and the largest moon in the entire Solar System.
mean element	One of several elements of an adopted reference orbit (see elements, orbital) that approximates the actual, perturbed orbit
venipuncture	The process in which the vein is punctured to draw a blood sample, to give medication, or to start an intravenous drip.
stationary phase	A stationary phase is a substance that shows different affinities for different components in a sample mixture in a separation of the mixture by chromatography
syngeneic bone marrow transplant	A bone marrow transplant where the donor is an identical twin to the patient.
poorly-differentiated lymphocytic lymphoma	The old Rappaport classification for the form of Non-Hodgkin's Lymphoma now known as follicular center cell lymphoma with a large component of small-cleaved cells.
mcd	DSN's maximum-likelyhood convolutional decoder, the Viterbi decoder.
triple point	The temperature and pressure at which the solid, liquid, and gaseous forms of a substance are at equilibrium.
imager	A device for producing an image.
temperature unit	A temperature unit is a measure of the average kinetic energy per degree of freedom of the constituent molecules.
nonpolar molecule	A molecule in which the center of positive charge and the center of negative charge coincide
gleevec	The new drug Gleevec was approved by the FDA May 10th 2001. It has been shown to be effective in creating lasting remissions for numerous cancers, including Leukemia and Lymphoma
atomic hydrogen	Individual hydrogen atoms that do not belong to molecules
segs	Sequence of Events Generation Subsystem.
crucial experiment	An experiment that has the power to decide between two competing theories.
litmus	A mixture of pigments extracted from certain lichens that turns blue in basic solution and red in acidic solution.
thermal radiation	The radiation emitted by any body or gas that is not at absolute zero.
compazine	A medication used to treat nausea and vomiting.
effective focal spot	The apparent size of the radiation source when viewed from the central axis of the useful beam.
computer-assisted drug design	Using computational chemistry to discover, enhance, or study drugs and related biologically active molecules.
annihilation radiation	A positron-negatron interaction in which the rest masses of both particles are ultimately given up as electro-magnetic radiation.
doppler shift	Effect on the wavelengths of light (or sound) emitted by a source at a distance that is increasing or decreasing in relation to the observer
halloysite	porcelainlike clay with a composition similar to that of kaolin but with more water and a distinct structure helium - atom consisting of two protons and two electrons
kerr solution	A solution to Einstein's equations describing the gravity produced by a spinning point of mass
spectral line	Electromagnetic radiation given off at a specific frequency by an atom or molecule
astrology	(a) The belief that human affairs and people's personalities and characters are influenced by (or encoded in) the positions of the planets
epitaxial	Refers to the formation of single-crystalline material upon a single-crystalline substrate by chemical reduction from the vapor phase
second law of thermodynamics	(a) A physical law formulated in the nineteenth century and stating that any isolated system becomes more disordered in time
geostationary	A geosynchronous equatorial circular orbit
argument	Angular distance.
selenography	the scientific analysis and mapping of the moon
tau	Thousand AU Mission.
universal time	(a) The local mean time of the prime meridian
radionuclide	radioactive nuclear species or nuclide
operator's station	The area where the control panel for the operation of an X-ray machine is located
mach number	(a) The ratio of the speed of a moving object (e.g
ic	Integrated Circuit
bel	A number used mainly in English-speaking countries to express the ratio of two powers as a logarithm to the base ten
bone marrow	The soft, spongy tissue in the center of large bones that produces white blood cells, red blood cells, and platelets.
francium	A radioactive element of the alkali-metal group
soluble salt	An ionic compound that dissolves in a solvent (usually water).
bond length	The average distance between the nuclei of two bonded atoms in a stable molecule.
celsius	Scale of temperature for which water freezes at 0 degrees and boils at 100 degrees (under standard conditions).
core	central part of Earth, having a radius of about 2100 miles
sublimation	The process by which solids are transformed directly into vapor without passing through the liquid state.
half life	The half life of a reaction is the time required for the amount of reactant to drop to one half its initial value.
total dose	The total ionizing dose received by the device from the various radiation environments.
subcutaneous	Under the skin.
atomic mass unit	convenient unit for measuring the mass of an atom or molecule: 1 atomic mass unit is defined as 1/12 the atomic mass of the most abundant carbon isotope,
sfof	Space Flight Operations Facility, Buildings 230 and 264 at JPL.
ideal gas	(a) A nondegenerate gas in which the individual molecules are assumed to occupy mathematical points and to have zero volume, and in which the mutual attraction of neighboring molecules is zero
radiosonde	A sounding balloon used to transmit information on Earth's upper atmosphere
quality	A term used to describe the penetrating power of x-rays and is related to the energies of the photons in the useful or primary x-ray beam.
ion	An atom with a net positive or negative electric charge, due to an unequal number of protons and electrons.
polymerize	To link smaller molecules together to form a larger molecule.
resolution	The degree to which fine details in an image are separated or resolved.
graft-verses-host disease	A complication that may develop after a bone marrow transplant in which the lymphocytes from the donated bone marrow react against the host's cells.
21-cm line	A spectral line of neutral hydrogen at the radio wavelength of of 21 cm.
tos	Transfer Orbit Stage, upper stage.
s	South.
forward bias	A term applied to an electronic device known as a diode - usually formed by a junction of p-type and n-type semiconductor material - in which current flows easily if the externally applied voltage has the correct polarity or direction
meteor	Brief streak of light seen in the night sky when a speck of dust burns up as it enters the upper atmosphere
inverse compton scattering	A collision between a photon and an energetic electron that transfers energy from the electron to the photon.
colloid	A substance containing very small particles (sizes in the range 10-9-10-5 m)
era	A system of chronological notation reckoned from a given date.
diic	Dielectric Isolated Integrated Circuit
congener	1
conic constant	A number used in optics to specify the shape of a surface which is a conic section, i.e
monochromatic	Radiation that has a single wavelength.
primary tumor	Tumor at the original cancer site.
cosmic rays	Highly energetic nuclei and particles, generally electrically charged, with energies ranging from 100 million eV to 10 million billion eV
barn	A unit area used in expressing the interaction cross-sections of atoms, nuclei, electrons, and other particles One barn is equal to 1E-24 square centimeters
great circle	An imaginary circle on the surface of a sphere whose center is at the center of the sphere.
spectrometer	An instrument that provides information on the bonding of an atom in a mineral by bombarding it with gamma rays and measuring small shifts in the velocity or energy of the gamma rays emitted
ammos	Advanced Multimission Operations System.
magnetic-dipole radiation	Radiation emitted by a rotating magnet
primaeval soup	Mixture of water and chemical ingredients that constituted the oceans on Earth about three or four billion years ago
neoplasm	Malignant (cancerous) growth.
zofran	(Generic name ondansetron Hcl) - an antiemetic (nausea suppression) drug commonly prescribed for chemotherapy induced nausea
immunophenotyping	Determining what kind of surface molecules are present on cells
biopsy	The removal of a sample of tissue followed by microscopic examination by a pathologist to see whether cancer cells are present.
transient x-ray sources	As of early 1974, four had been detected: Cen X-2, Cen X-1, 2U 1543-47, and Cep X-4
swg	Science Working Group.
18th century scientist	a scientist born between 1700 and 1800 AD
mechanics	The study, in physics, of the influence of forces.
galaxy counts	A quantitative measure of how many galaxies there are in each range of luminosity and at each range of distance from earth
seta	Systems Engineering Test and Analysis
multiplex	Combining many signals into one or a small number of signals
activity	Symbol: A For a radioactive substance, the average number of atoms disintegrating per unit time
photovoltaic	Materials that convert light into electric current.
carcinogen	An agent that causes cancer.
oxide	A binary compound that contains oxygen in the -2 oxidation state.
t cell	A type of lymphocyte that attacks any foreign substance in the body
after-image	An image seen after the eye's retina has been exposed for a time to an intense or stationary light source
adhesion	A force of attraction between atoms or molecules of different substances
monomer	A small molecule that is linked with large numbers of other small molecules to form a chain or a network (polymer).
aurora	Illumination of the night sky, caused when electrons and protons from space collide with atoms and molecules of air in the Earth's upper atmosphere
parabola	A curve that describes both the cross-section of a reflector that focuses rays to a point and the orbit of a body having escape velocity.
bit	(a) In computer terminology, a shortened form for binary digit (0 or 1)
shell	A surface made of thin material.
attometer	10-18 meter.
ob	Spectral type O or B - that is, hot and blue
alara	An acronym for As Low As Reasonably Achievable, economic and social factors being taken into consideration
elevation	The angle in degrees above the horizon toward the zenith or overhead point
eutectic	form of a compound that has the lowest possible melting point
t	Tera, a multiplier x1012, from the Greek teras (monster)
echelon	A type of diffraction grating consisting of a number of equal thin glass sheets stacked on a slant
lymphedema	The swelling of the arms and or legs that may result from the blockage or removal of lymph nodes
multimirror	Telescope design employing several mirrors to collect and focus electromagnetic waves, as in ESA's XMM-Newton space observatory.
biochemistry	The chemical processes of living organisms; the scientific study of those processes.
happ	Hardness Assurance Program Plan
w	Watt, a measure of electrical power equal to potential in volts times current in amps.
tektite	A small glassy body containing no crystals, probably of meteoritic origin and bearing no antecedent relation to the geological formation in which it is found
f number	Ratio of the focal length to the diameter of a lens
octet	A set of eight valence electrons.
time delay	see Dispersion
g	Giga, a multiplier, x109, from the Latin "gigas" (giant)
blood cell	A general term describing the three cellular components of blood (white blood cells, red blood cells, and platelets), all which are made in the bone marrow.
chemistry	The scientific study of chemicals and chemical reactions.
octet rule	A guideline for building Lewis structures that states that atoms tend to gain, lose, or share valence electrons with other atoms in a molecule until they hold or share eight valence electrons
universal indicator	A universal indicator is an indicator which undergoes several color changes over a wide range of pH
gluon	The force-carrying particles associated with the strong interactions, the forces which bind quarks inside of protons and neutrons
sextant	Instrument employed to measure the elevation of astronomical objects above the horizon
collimator	A device for restricting/confining/limiting a beam of radiation within an assigned solid angle.
filter	Accessory used with an optical instrument or detector of electromagnetic radiation to either narrow down the wavelength band or to reduce the total intensity passing into the instrument.
friedmann models	A general class of cosmological models that assume the Universe is homogeneous and isotropic on large scales and that allow the Universe to evolve in time
incomplete octet	1
cp violation	(a) A reaction between subatomic particles is said to be a "CP violating" reaction if the reaction produces a different result when the electrical charges of the particles are changed to their opposites and the mirror image of the particle trajectories is used
krzeminski's star	See Cen X-3
metabolite	A compound produced by metabolic reactions.
installation	The location where one or more reportable sources of radiation are processed (located).
capture orbit	The first orbit of a spacecraft after it has been captured by the gravitational attraction of a celestial body
tail	The long streamer (about 107 km long; density about 10-18 atm) behind the comet head
atom	The smallest unit of an element which keeps the element's characteristics
port	A small plastic or metal container surgically placed under the skin and attached to a central venous catheter inside the body. Blood and fluids can enter or leave the body through the port using a special needle.
support group	Group of individuals who meet on a regular basis to exchange mutual support, often focusing on a shared area of difficulty
mccc	Mission Control and Computing Center at JPL (outdated).
tlp	DSN Telemetry Processor within the DTT Downlink Channel.
mc-cubed	Mission Control and Computing Center at JPL (outdated).
antipyretic	A substance that can lessen or prevent fever.
fermi's question	The question of why, if spacefaring extraterrestrial civilizations exist, their representatives haven't visited Farth
sink	In general, a region where energy is given up, in contrast to a source, where energy is released
quantum solid	A degenerate gas in which the densities are so great that the nuclei are fixed with respect to each other so that they resemble a crystalline lattice.
jfet	Junction Field Effect Transistor
jgr	Journal Of Geophysical Research.
angular frequency	(Pulsatance) Symbol: The number of complete rotations per unit time
c ring	The innermost of the three rings of Saturn that are easily seen in a small telescope.
waves	Propagation of energy by means of coherent vibration
toy theory	A theory which is known to be too simple to describe reality, but which is nonetheless useful for theorists to study because it incorporates some important features of reality
law of multiple proportions	When one element can combine with another to form more than one compound, the mass ratios of the elements in the compounds are simple whole-number ratios of each other
rocket	Commonly used term for a launch vehicle.
baryogenesis	(a) The process by which the Universe's net baryon number was generated
complex analytic	A particular property of mathematical representations of physical or mathematical systems
solar cycle	The 11-year period between maxima (or minima) of solar activity
x-band	A band of radio frequencies extending from 5200 to 10 900 MHz
mendelevium	A radioactive transuranic element of the actinoid series, not found naturally on Earth
neutron	A particle commonly found in the nucleus of an atom with approximately the mass of a proton, but zero electrical charge.
quantum cosmology	(a) The study of the Planck era
hidden mass	Matter whose presence is inferred from dynamical measurements but which has no optical counterpart
winding mode	A string configuration that wraps around a circular spatial dimension
photometric linearity	The ability of a photometric system to yield a linear relationship between the radiant power incident on ist detector and some measurable quantity provided by the system.
molecule	The smallest unit of matter that retains the properties of a chemical compound
node	(astronomy) a point where an orbit crosses a plane.
elliptical orbit	An orbit which describes an ellipse or oval shape.
ultraviolet	That part of the electromagnetic spectrum with wavelengths between 5 and 400 nanometers (nm)
zel'dovich spectrum	A particular prescription for how much clumping of matter should occur on each length scale
zonal wind	Atmospheric wind component which flows along the latitude.
gamma-ray astronomy	Field of astronomy which studies very energetic processes
pda	Photodiode array.
mean free time	For gas atoms or molecules in a container, or electrons and impurity atoms in a semiconductor, the average time between particle collisions
ssi	Solid State Imaging Subsystem, the CCD-based cameras on Galileo.
systemic	Affecting the whole body rather than one part or organ.
j-value	Value of the total angular momentum (orbital plus spin)
tdm	Time-division multiplexing.
cds	Correlated Double Sampling A technique used with CCDs to remove an unwanted electrical signal, associated with resetting of the tiny "on-chip" CCD output amplifier, which would otherwise compromise the performance of the detector
charm	(a) The fourth flavor (i.e
drag	Effect of an atmosphere that slows a spacecraft and forces its orbit to decay.
added filter	Sheets of metal (usually aluminum or its equivalent) which are placed in the direct path of the x-ray beam.
mis	Metal Insulator Semiconductor
diamond	A crystalline form of carbon, made of a network of covalent, tetrahedrally bound carbon atoms.
polarity	A property associated with molecules when the center of positive charge and the center of negative charge don't coincide
photomultiplier	Device used in photometry for the amplification of light by the release and acceleration of electrons from a sensitive surface
biochemistry	The chemistry of living things, including the structure and function of biological molecules and the mechanism and products of their reactions.
chronic	lasting for a long period of time or marked by frequent recurrence.
moso	Multimission Operations Systems Office at JPL.
rotational invariance	The property of being unchanged by a rotation
bone marrow suppression	A decrease in the number of blood cells produced; it may be a result of cancer treatment or tumor invasion of bone marrow.
galactic	1
gaia hypothesis	hypothesis that the biosphere has an important modulatory effect on the surrounding atmosphere
matter era	The era following the radiation era
longitude	An east-west coordinate on the earth's surface; the angular distance, measured east or west along the equator from the Greenwich meridian, to the meridian passing through a place.
graceful exit problems	A problem of the original formulation of the inflationary theory, in which the formation of bubbles at the end of inflation destroys the homogeneity of the universe
fornax a	A 10th-magnitude S0 galaxy (NG6 1316), which is a strong radio source
signal-to-noise ratio	The ratio of the amount of intelligible meaning in a signal to the amount of background noise
d region	A daytime region of the ionosphere ranging in height from approximately 30-50 miles
wien's law	The wavelength at which a blackbody emits the greatest amount of radiation is inversely proportional to its absolute temperature
primary standard	A stable, high-purity material used in titrations and other chemical analyses to prepare solutions of precisely known concentration, or to determine the concentrations of substances which react with the primary standard material
raoult's law	The vapor pressure of a solvent in an ideal solution equals the mole fraction of the solvent times the vapor pressure of the pure solvent.
b-cell lymphomas	Non-hodgkin's lymphomas that arise from cancers in B-cells. See the B-cell lymphoma page for more information.
extrasolar planet	A planet orbiting a star other than the sun
elastic potential energy	potential energy which is stored when a body is distorted
rate law	A rate law or rate equation relates reaction rate with the concentrations of reactants, catalysts, and inhibitors
free radical	atom or group of atoms having at least one unpaired electron
amphi-	A prefix used to name certain members of a series of geometric isomers or stereoisomers.
immunotherapy	Treatment of disease by inducing, enhancing, or suppressing an immune response
w boson	see Intermediate Vector Boson.[H76]
khz	kilohertz.
hydration	Combination with water.
rotation	Of a single body in space: spinning on an axis
debulking	reducing the size of a tumor often through surgery or through radiation therapy.
cmos	PMOS and NMOS utilized as a complementary pair
k magnitude	The magnitude derived from observations at 2.2 microns
xmm-newton mission	ESA's X-ray space observatory mission, with its X-ray Multi-Module design using three telescopes each with 58 nested X-ray mirrors
prognosis	The probable outcome of a disease; the prospect of recovery.
honeycomb mirrors	A construction method for a large mirror in which the back is hollowed-out to leave a ribbed structure that resembles a honeycomb
ab initio	A calculation or prediction that is based purely on theory rather than on experimental data
creationism	Belief that the universe was created by God in the relatively recent past, as implied by literal interpretations of biblical chronology, and that the species of terrestrial life did not arise through Darwinian evolution but, rather, all came into existence at once.
four-vector	A quantity that has four components which, under the Lorentz transformation, transform like space and time
mgn	The Magellan spacecraft.
liquid element	element which is in liquid form at standard temperature and pressure
bvr	DSN Block Five (V) Receiver.
coded mask	Mask made for example of lead, tungsten, aluminium etc
oss	Office Of Space Science, NASA
supercritical fluid	A fluid state that occurs when the pressure and temperature exceed the substance's critical pressure and critical temperature
krüger 60 ab	A faint, twelfth-magnitude dM binary (P = 44.5 years) in the Solar neighborhood (3.93 pc distant)
hubble expansion	..
craf	Comet Rendezvous / Asteroid Flyby mission, cancelled.
isomer	Nucleus with the same A and Z numbers but in different energy states.
dc	Direct current.
neutron	Particle in atomic nuclei
nonelectrolyte	A nonelectrolyte is a substance which does not ionize in solution.
dec	Declination.
magnitude	A measure
grazing incidence	Describes the low angle of incidence of incoming electromagnetic waves on a reflecting surface
fourier analysis	The analysis of a periodic function into its simple harmonic components
plane	A surface upon which the image of all points in the field of view of an optical instrument is created.
kinetic energy	The energy associated with motion; the work that must be done to change a body from a state of rest to a state of motion, equal to 1/2 mv2 for a body of mass m moving at velocity v.
absorption of radiation	No medium transmits radiation without some energy loss
aberration	Property of an optical system that causes an image to have certain easily recognisable flaws
nova	A star that experiences a sudden outburst of radiant energy, temporarily increasing its luminosity by hundreds to thousands of times before fading back to its original luminosity.
centimeter	10-2 meter.
critical temperature	the temperature at which a continuous phase transition occurs
scientific method	An inefficient but highly successful method of knowledge construction based on experimental testing of hypotheses.
orbit	The path through space of one celestial body or spacecraft about another.
spectrophotometer	An instrument for measuring the amount of light absorbed by a sample.
billion	One billion equals one thousand million.
recombination	The capture of an electron by a positive ion.
harkins's rule	The rule that atoms of even atomic number are more abundant than those of odd atomic number
geology	Scientific study of the dynamics and history of the earth, as evidenced in its rocks, chemicals, and fossils
terminal	Describes an advanced disease with limited life expectancy.
visible light	Visible light is electromagnetic radiation with a wavelength between 400 and 750 nm.
optical fibres	Glass and transparent plastics can be made into very thin wires or fibers
rem	Receiver Equipment Monitor within the Downlink Channel (DC) of the Downlink Tracking & Telemetry subsystem (DTT).
atomic mass	Mass of a neutral atom of a nuclide; also called "atomic weight." The atomic weight of an element is the weighted average of each isotope.
ortho-spectrum	Spectrum of triplet (l = l)
measurement	Measurement is the collection of quantitative data
km	Kilometers.
ozone layer	A layer in the lower part of Earth's stratosphere where the greatest concentration of ozone (03) appears
tautomer	A structure formed by facile motion of a hydrogen from one site to another within the same molecule.
string mode	A possible configuration (vibrational pattern, winding configuration) that a string can assume
half-life	The time in which half the atoms of a particular radioactive substance disintegrate to another nuclear form.
amor asteroids	Group of near-Earth asteroids (NEAs) named after asteroid 1221 Amor
h and k lines	The two closely spaced lines of singly ionized calcium at 3968 and 3934 Å, respectively
downlink	Signal received from a spacecraft.
iemp	Internal Electromagnetic Pulse
occupational dose	Means the dose received by any individual in the course of employment
minkowski space-time	space and time considered together, with special importance attached to the progress of a light flash, and to the light-cone and the `interval'
quark	Fundamental particles from which all hadrons are made
ft-values	t = half-life of the -unstable nucleus, and f stands for an integral which depends on the -decay energy and the type of transition
boyle's law	(a) At a constant temperature, the pressure of a fixed mass of a gas is inversely proportional to its volume: i.e
ultraviolet	(a) Part of the electromagnetic spectrum immediately above visible light (but below Gamma-rays and X-rays); it therefore comprises a range of radiation of shorter wavelength and higher frequency than those of visible light
minute of arc	A unit of angle equal to 1/60 of a degree
fall	A "fall" as opposed to a "find" is a meteorite whose arrival on Earth is witnessed
dcpc	The DSN Downlink Channel Processor Cabinet, one of which contains a DSN Downlink Channel, DC.
multiple bond	Sharing of more than one electron pair between bonded atoms
16th century scientist	a scientist born between 1500 and 1600 AD
bleomycin	A chemotherapy drug commonly used to treat Hodgkin's disease
ecliptic	The mean plane of the Earth's orbit around the Sun.
cretaceous	The geological Period from 144 to 65 million years ago
energy spectrum	(In cosmic-ray studies, a plot of number of particles versus energy
separation	The instant at which a satellite is released from its launcher.
binocular vision	Using two eyes to see an object
geocentric cosmology	School of ancient theories that depicted the earth as standing, immobile, at the center of the universe.
isoe	Integrated Sequence of Events.
amplitude	(a) The maximum value of a varying quantity from its mean or base value
ritchey-chretien	A modern optical design for two-mirror reflecting telescopes
toro	An Earth-crossing asteroid (No
triton	The nucleus of the tritium atom
divalent anion	An ion with a charge of -2.
bernoulli's theorem	Along a streamline the total energy per unit mass (including the internal energy and the pressure head p/) of an element of fluid remains constant as it moves
phospholipid	An ester of glycerol with two fatty acids and phosphoric acid (H3PO4) or a derivative of phosphoric acid group (like H2PO4CH2CH2N(CH3)3)
astronomical twilight	For technical definition, please follow this link to the U.S
mit	Massachusetts Institute of Technology.
mon	DSN Monitor System
oncologist	A doctor who specializes in the study, diagnosis, treatment and rehabilitation of individuals with cancer.
absorptivity	Symbol: The ratio of the radiant or luminous flux absorbed by a body or material to the incident flux
plate tectonics	model of the structure of Earth in which the surface consists of a small number of semirigid plates floating on a viscous underlayer [
phz	Petahertz (1015 Hz).
photoelectric magnitude	The magnitude of an object as measured with a photoelectric photometer
amino acid	acid containing the amino (NH
absorption	The transfer of energy from an x-ray beam to the atoms or molecules of the matter through which it passes
gamma rays	Electromagnetic radiation released during a nuclear transition.
kilovolt peak	A unit of maximum or crest value of electrical potential difference between the anode and cathode of an x-ray tube; determines the penetrating ability of x-rays and revers to the "quality" of x-rays.
strong nuclear force	A short-range nuclear force that operates within an atomic nucleus.
plane grating	The grating has a plane substrate and straight and equidistant grooves.
pressure broadening	Line broadening caused by pressure.
ohmmeter	An instrument for measuring electrical resistance.
eumetsat satellite	meteorological satellite launched and maintained by Europe's Meteorological Satellite Organization
proton	Positively charged constituent of all atomic nuclei
ethane	A colourless and odourless gas that belongs to the alkane series of the hydrocarbons.
cure	in the case of lymphoma, the term used when there is no sign of disease present in the body and adequate time has passed so that the chances of recurrence are small.
silicate	1
auger effect	(a) The ejection of an electron from an atom or ion without the emission of radiation (x-rays or gamma rays)
secondary cosmic rays	Atomic fragments - mainly muons - produced by collisions between primary cosmic rays and the molecules in Earth's atmosphere
periodic law	The periodic law states that physical and chemical properties of the elements recur in a regular way when the elements are arranged in order of increasing atomic number.
secondary or stray radiation	Mean radiation not serving any useful purpose
splenomegaly	Enlargement of the spleen.
short term memory	Short term memory is a mechanism for storing temporary information, such as where you parked your car or numbers in a simple arithmetic problems.
co-moving coordinate	A set of coordinates which do not change in an expanding (or otherwise moving) medium
geodetic coordinates	The latitude and longitude of a point on the Earth's surface determined from the geodetic vertical (normal to the specified spheroid)
ionized hydrogen	A hydrogen atom that has lost its electron
element	Different elements are distinguished by the number of protons in their nuclei
opacity	(a) A measure of the resistance of a medium to the transmission of visible light or other forms of radiation
sec	Abbreviation for Second.
rotation	The action of moving in a circle around an axis or fixed point.
semi-major axis	Half the length of the major axis of an ellipse; a standard element used to describe an elliptical orbit
kuiper bands	Bands in the spectra of Uranus and Neptune at wavelengths of 7,500 Å, indicating the presence of methane
starch	A polysaccharide used by plants to stockpile glucose molecules
ascending node	The point at which an orbit crosses a reference plane (such as a planet's equatorial plane or the ecliptic plane) going north.
crust	The outermost solid layer of the Earth or of similar bodies.
topography	The surface elevation of land and its variations.
transputer	A compact computer chip with a special design for linking to other transputers to make the program run faster
isotropic	Having uniform properties in all directions.
chaotic dynamics	time-dependent aperiodic regime in which individual histories corresponding to initially close states tend subsequently to diverge exponentially
indicator	A substance that undergoes an sharp, easily observable change when conditions in its solutions change
cdr	GCF central data recorder.
radiography	utilizing ionizing radiation, this technique involves making shadow images on photographic emulsions
kourou	Coastal town of French Guiana, just north of the Equator, where France created a launch site in 1964
voltammeter	An instrument for measuring voltages and amperages.
xeus mission	Future global X-ray astronomy mission
quantum	The smallest ‘unit’ of energy
jump conditions	The conditions for jumps in pressure and density (or temperature or energy) across a shock wave
magnification	The effect of an optical system on the apparent angular size of an object
hci	Hardness Critical Item
vela satellite	A sequence of satellites launched to monitor possible violations of the nuclear test ban treaties
quantum theory	(a) A theory which seeks to explain that the action of forces is a result of the exchange of sub-atomic particles
luminous flux	Symbol: v The rate of flow of energy of visible radiation
tetrahedral	A molecular shape that results when there are four bonds and no lone pairs around the central atom in the molecule
valence electron	In an atom, an electron in an incompletely filled (usually outer) shell, available for chemical bonding to form a molecule
fet	Field Effect Transistor A tiny transistor amplifier in which the current flow between two terminals, called the source and the drain, is controlled by the electric field generated inside the silicon by an external voltage on a surface called the gate electrode
simulations	In science, simulations of physical systems with a computer
pmos	P-channel MOS
sugar	A carbohydrate with a characteristically sweet taste
developer	The chemical solution (alkaline) use in film processing that makes the latent image visible.
lithosphere	outer (rocky) layer of the solid Earth, usually taken to be about 50 miles in depth
particle	Fundamental unit of matter and energy
rrc star	RR Lyr star characterised by equally long rise and fall time
quantum defect	The principal quantum number responsible for a spectral series, minus the Rydberg denominator for any actual spectral term of the series
t-shape	A molecular shape that results when there are 3 bonds and 2 lone pairs around the central atom in the molecule
isotropic	(a) Having equal and uniform properties at all points and in all directions
sedimentation	Separation of a dense material (usually a solid) from a less dense material (usually a liquid) by allowing the denser material to settle out of the mixture.
uranium-lead dating	A method of radioactive dating used for estimating the age of certain rocks
luminiferous ether	A material that, prior to special relativity, was believed to permeate all of space, allowing the propagation of light
b	Bel, a unit of ratio equal to ten decibels
hygroscopic	Able to absorb moisture from air
mie scattering	Scattering of light (without regard to wavelength) by larger particles, such as those of dust or fog in Earth's atmosphere.
planck's law	The relationship between the wavelike and particle-like (photon) properties of Electromagnetic radiation
molar	1
emollient	A substance added to a formulation that gives it softening ability
photoelectric effect	A photon is absorbed in an interaction with an electron causing the struck electron to be ejected from the atom.
open system	a system communicating with the environment by the exchange of energy and matter.[D89]
resolution	The higher the resolution of a telescope, the more details we can see from the images obtained on it
rtg	Radioisotope Thermo-Electric Generator onboard a spacecraft.
repeats/retakes	Additional radiographs taken because of technical or mechanical error
kolmogorov-smirnov test	A nonparametric test used in statistics
mandrel	Metallic structure upon which articles to be turned are placed
mega-	A prefix meaning 106
gamma	Unit of magnetic field intensity equal to 10-5 gauss
geometric unsharpness	Unsharpness of the recording image due to the combined optical effect of finite size of the radiation source and geometric separation of the anatomic area of interest from the image receptor and the collimator.
numerical aperture	Abbreviation: NA
logistic equation	models the growth of a population as a competition between self-reproduction on the one side and inhibition arising from density-dependent effects on the other side
quantum hall effect	in a two-dimensional electron system at sufficiently low temperature and in sufficiently high magnetic field the ratio of the current to the voltage applied in a direction perpendicular to the current is very accurately a multiple (integer or fraction with small odd denominator) of e2/, where e is the electron charge and is Planck's constant
propellant	1
magnification	The ratio of image size to object size
lmc	Link Monitor and Control subsystem at the SPCs within the DSN DSCCs.
intermediate grade	A grade of Non-Hodgkin's denoting usually moderate growth
milli-	A prefix meaning 10-3
first mission	See Herschel mission.
nsp	DSN Network Simplification Project
thermometry	The science of temperature measurement.
omicron2 eridani	A triple star that lies 16 light-years away and has the first white dwarf ever discovered
selectron	The supersymmetric partner of the electron.
reduction	A chemical reaction in which electrons are gained, or the chemical addition of hydrogen takes place.
formaldehyde	H2CO -- An organic molecule, the first polyatomic molecule to be discovered in interstellar space (in 1969)
standard solution	A solution of precisely known concentration.
isochore	A contour line that corresponds to values measured at identical volumes
asic	Application Specific Integrated Circuit
m	milli- multiplier of one one-thousandth, e.g
work-energy theorem	formula showing work done on rigid body by net force changes energy of the body
source function	The amount of radiant energy per unit mass per unit solid angle emitted in a specified direction
euler number	A number used in fluid dynamics defined by p / v2, where p is pressure, density and v velocity
induction	System of reasoning in which the conclusion, though implied by the premises and consistent with them, does not necessarily follow from them
energy unit	(1) The capacity to do work
zero-point pressure	The pressure contributed by degenerate electrons, which do not come to rest even at absolute zero
purging	In cancer treatment purging refers to the removal of cancer or T cells in bone marrow or stem cells prior to BMT or PBSCT.
quality assurance	A management tool that includes policies and procedures designed to optimize the performance of facility personnel and equipment.
thio-	A prefix that means, "replace an oxygen with sulfur"
vein	A blood vessel that carries blood to the heart.
cornerstone	Category name given to the European Space Agency's key missions in its long-term space science programmes Horizon 2000 and Horizon 2000+.
j-j coupling	see LS coupling [H76]
multi-pinned-phase	Also multi-phase-pinned
monoclonal antibody	An artificially made antibody used against a specific antigen
force	(a) Agency responsible for a change in a system
matter	A physical substance, having mass and occupying space
siemens	The SI unit of electrical conduction (reciprocal ohm)
orthonormal tetrad	A set of four mutually orthogonal unit vectors at a point in spacetime, one timelike and three spacelike, which give the directions of the four axes of a locally Minkowskian coordinate system
monitor	Optical instrument used to observe the sky by itself and sometimes as a complement to another instrument.
lymphoma	A subset of cancers that begin in the lymph system
frame of reference	A set of axes to which positions and motions in a system can be referred
checkout	A test procedure needed to assess the correct functioning of a spacecraft's performances.
sterility	Inability to conceive or produce a child.
tropopause	Upper boundary of the troposphere, where the temperature gradient goes to zero.
taylor instability	A hydrodynamic instability which occurs whenever there is a density inversion
peer support	Structured relationship in which people meet in order to provide or exchange emotional support with others facing similar challenges.
fossils	Geological remains of what was once a living thing
lithium star	C star with a very strong Li I 6078 line.
aluminum equivalent	The thickness of aluminum affording the same attenuation, under specified conditions
coherent	(a)Two sources of waves are said to be coherent if there is a constant relationship between the phases of the waves emitted by them
refractory	Not yielding (at least not yielding readily) to treatment.
terminus	The end of a polymer molecule.
atom	The smallest particle of an element which can enter into a chemical combination.
unsettled	With regard to geomagnetic activity, a descriptive word defining conditions between quiet and active, specifically meaning that the A index is between 8 and 15.
carbon dioxide	A molecule consisting of one carbon atom and two oxygen atoms (CO2)
ionization	(a) Loss or gain by an atom of one or more electrons, by which process the atom becomes an ion and instead of being neutral, has a charge: positive if it has lost an electron, negative if it has gained one
organics	Carbon-based material.
measurements	Measurement of physical and chemical parameters of a physical object from a remote location.
kreep	Lunar basaltic material rich in radioactive elements
vinblastine	A chemotherapy drug commonly used to treat Hodgkin's disease
hera	Unofficial name for Jupiter VII
law	A theory of such wide and invariable application that its violation is thought to be impossible
total filtration	The sum of the inherent and added filters.
huyghenian region	The brightest portion of the Orion Nebula
arcsecond	One sixtieth of an arcminute, or 1/3600 of a degree
kinetic temperature	A measure of the average random motion of the particles in a system
faraday effect	An effect occurring in HII regions in which a magnetic field causes a change in the polarized waves passing through (see Faraday Rotation)
closed space	A space of finite volume but without any boundary (in the cosmological context)
fornax	1
intrinsic brightness	The amount of light an object actually emits, as opposed to how bright the object looks from Earth
demp	Dispersed Electromagnetic Pulse
field equations	Equations which relate to one of the fundamental fields of force
lanthanide contraction	An effect that causes sixth period elements with filled 4f subshells to be smaller than otherwise expected
white supergiant	A supergiant star with a spectral type of A
gal	Unit of gravity field measurement corresponding to a gravitational acceleration of 1 cm/sec2.
maser	A microwave travelling wave tube amplifier named for its process of Microwave Amplification by Stimulated Emission of Radiation
alignment	Process of mounting optical elements and adjusting their positions and orientations so that light follows exactly the desired path through the instrument and each optical element performs its function as planned.
astigmatism	Failure of an optical system, such as a lens or a mirror, to image a point source of light as a single point.
tumor	An abnormal mass of tissue that results from excessive cell division
rom	Read Only Memory.
clocking	The process of raising and lowering the voltages between two levels - high and low - on the electrodes or gates of a CCD in order to move charges from one pixel to the next
service module	Part of a satellite which contains the housekeeping equipment, i.e
optical light	The light that can be detected by the human eye
scintillation	(a) In radio astronomy, a rapid oscillation in the detected intensity of radiation emitted by stellar radio sources, caused by disturbances in ionized gas at some point between the source and the Earth's surface (usually in the Earth's own upper atmosphere)
k	Kilo, a multiplier, x103 from the Greek "khilioi" (thousand)
ipac	Infrared Processing and Analysis Center at Caltech campus on Wilson Avenue in Pasadena.
f-electron	An orbital electron whose l quantum number is 3
boltzmann equation	A statistical definition of entropy, given by S = k ln W, where S and k are the entropy and Boltzmann's constant, respectively, and W is the probability of finding the system in a particular state.
soe	Sequence of Events.
sun synchronous orbit	A spacecraft orbit that precesses, wherein the location of periapsis changes with respect to the planet's surface so as to keep the periapsis location near the same local time on the planet each orbit
apogee	The most distant point from Earth on a satellite's orbit.
chronic exposure	Irradiation which is spread out over a period of years
photometer	A device so designed that it furnishes the ratio, or a function of the ratio, of the radiant power of two electromagnetic beams
van der waals equation	A semiempirical equation that describes the relationship between pressure (P), volume (V), temperature (T), and moles of gas (n) for a real gas
tev	Equal to one teraelectron volt, or 1,000 GeV
climate	long-term manifestations of short-term atmospheric variations
hematology	The study of blood, blood-producing organs, and blood disorders
altitude	Height in space of an object or point relative to sea level or ground level.
drifting	refers to a signal with an apparent time rate of change in its typical frequency
isotope	A chemical element is characterised by the number of protons in its atomic nucleus
chaos	originally used by the Greeks to describe the limitless void, it is now used to describe unpredictable and apparently random structures
five-minute oscillations	Vertical oscillations of the Solar atmosphere with a well-defined period of 5 minutes
prebiotic	relating to the chemical or environmental precursors of the origin of life
benign tumor	A noncancerous growth that does not spread to other parts of the body.
purine	nitrogen base that forms a component (with sugar and phosphate of nucleotides and nucleic acids
micron	Obsolete terms for micrometer, µm (10-6 m).
ascending node	In the orbit of a Solar-System body, the point where the body crosses the ecliptic from south to north: for a star, out of the plane of the sky toward the observer
photon	The carrier of a quantum of electromagnetic energy.
tera	A prefix meaning 1012
chandler wobble	A small motion in the Earth's rotation axis relative to the surface, discovered by American astronomer Seth Carlo Chandler in 1891
accretion	Collection of material together, generally to form a single body.
pn10	Pioneer 10 spacecraft.
mem	Maximum Entropy Method: An image reconstruction methodology which defines a measure of information content and seeks to maximize it
asterism	Rare
butterfly effect	Any effect in which a small change to a system results in a disproportionately large disturbance
frame transfer	A CCD construction in which one half of the imaging area of the device is purposely covered with a mask opaque to light to provide a temporary charge storage section
data	Facts (in the form of values, quantities given by an instrument) from which other information may be inferred
conservative scattering	Scattering that occurs in the absence of absorption
canal	(astronomy) an indistinct surface feature of Mars once thought to be a system of channels; they are now believed to be an optical illusion.
serendipity	An event occurring by chance, usually with beneficial or happy consequences.
state of matter	There are three common states of matter: gases, liquids, and solids
osmotic pressure	Pressure which must be applied to a solution to prevent water from flowing in via a semipermeable membrane.
mirror	An optical element that reflects electromagnetic waves (such as visible light, infrared, gamma or X-rays..) towards a camera or detector.
coplanar	Lying in one plane
detail	Refers to the sharpness of structure lines or contour lines on the processed film.
cnes	Centre National d'Etudes Spatiales (Paris, France)
secondary malignancy	Cancer that develops after treatment for a first cancer but is not related to the first cancer
twistor theory	Model of the Universe proposed by Roger Penrose, based on the application of complex numbers (involving (-1)1/2) used in calculations in the microscopic world of atoms and quantum theory to the macroscopic ordinary world of physical laws and relativity
experiment	An experiment is direct observation under controlled conditions
ablation	Removal of material from a solid by heating, vaporization or collisions
k edge	The absorption edge of the K shell (see absorption edges).
antiparticle	Particles with identical mass and spin as those of ordinary matter, but with opposite charge
diode	Semiconductor electronic component
regimen	A combination of drugs and how they are administered.
unit	A standard for comparison in measurements
hematocrit	The number of red blood cells within a sample of blood
f region	Region of the ionosphere above the F layers
action	A quantity related to the momentum and position of a body or system of particles
nautical twilight	For technical definition, please follow this link to the U.S
cosmic light	A small (no more than 1%) contribution by extragalactic sources to the background glow of the night sky
oncology	Study of the development, diagnosis, treatment, and prevention of cancer.
archaea	The third major domain of life, after bacteria and eukaria
baryon	(a) A particle made of three quarks
informed consent	legally required procedure to ensure that a patient knows about the potential risks and benefits of a treatment before it is started.
systems analysis	analysis of the response to inputs of a set of interconnected units whose individual characteristics are known
superior conjunction	(astronomy) the alignment of the Earth and a planet on the opposite side of the sun.
jeans length	(a) The critical wavelength (J = cs ( / G0)1/2, where cs is the isothermal sound speed in the medium) at which the oscillations in an infinite, homogeneous medium become gravitationally unstable
inguinal	The pubic/groin region
doppler effect	The effect on frequency imposed by relative motion between transmitter and receiver
encke's division	A region of decreased brightness in the outermost ring of Saturn.
forbidden	Processes can be naively imagined that might occur, but should not occur according to the predictions of the Standard Model
getter	A chemical absorption method of removing (pumping) gas from a chamber by tying up molecules on a surface
multi-wavelength	Observation of a celestial object at different wavelengths, with (possibly) different instruments.
complex ion	An ion formed by combination of simpler ions or molecules; for example, Co2+ combines with six molecules of water to form the complex ion Co(H2O)62+.
gll	The Galileo spacecraft.
semi-convection	The partial convective mixing that takes place in a convectively unstable region where stability can be attained by the results of the mixing before the region is completely mixed
titration curve	A plot that summarizes data collected in a titration
plastic	any of various cytoplasmic organelles of photosynthetic cells that serve in many cases as centers for metabolic activity
a	Ampere, the SI base unit of electric current.
cti	Charge Transfer Inefficiency
twt	Traveling Wave Tube, downlink power amplifier in a spacecraft telecommunications subsystem, the final stage of amplification for downlink (same unit as TWTA).
ccs	Computer Command subsystem on board a spacecraft, similar to CDS.
uls	Ulysses spacecraft.
plasma	A completely ionized gas; the so-called fourth state of matter (besides solid, liquid, and gas) in which the temperature is too high for atoms as such to exist and which consists of free electrons and free atomic nuclei.
quadrant	An instrument, based on a quarter of a circle, employed to measure the altitude above the horizon of astronomical bodies
zincography	Process of etching unprotected parts of a zinc plate with strong acids to produce a printing surface.
convex	Surface curved like the outside of a circle.
calculus	A branch of mathematics that permits computations involving rates of change (differential calculus) or of the contribution of an infinite number of infinitesimal quantities (integral calculus).
torus	The topological name for the shape of a donut
dispersion	The separation of a beam of light into the individual wavelengths of which it is composed by means of refraction or diffraction.
kayser	A wavenumber
vitamin	A substance that is critical for proper functioning of a living organism that the organism is unable to produce in sufficient quantities for itself.
mri	See Magnetic Resonance Imaging
kiel classification	A classification system introduced in 1974 for differentiating types of Non-Hodgkin's lymphoma. Popular in Europe
dna	The part of the cell that contains and controls all genetic information.
seit	Systems Engineering Integration & Test
transfer function	mathematical relationship between the output of a system and its input
contrast	In radiology, _______ is defined as the difference in density between light and dark areas on the processed film.
pds	Planetary Data System.
imp	Integrated Master Plan
valence bond	In the valence bond theory, a valence bond is a chemical bond formed by overlap of half-filled atomic orbitals on two different atoms.
absolute neutrophil count :	The total number of neutrophils, a special form of white blood cells in the body.
kilovolt	A unit of electrical potential difference equals to 1,000 volts.
geomagnetic storm	A worldwide temporal disturbance of the earth's magnetic field
ozone	A molecule consisting of three oxygen atoms (O3)
isobaric	Having constant pressure.
density	Mass per unit of volume.
sts	Space Transportation System (Space Shuttle).
evdp	Elemental Volume Dose Program
molecular sieve	A material that contains many small cavities interconnected with pores of precisely uniform size
wino	The supersymmetric partner of the W boson [K2000]
octave	The span over which the frequency doubles; e.g
malignant	Cancerous (see Cancer).
geo	Geosynchronous Earth Orbit.
altitude-azimuth	(a) Comprising a means of measuring or precisely locating in coordinates the position of objects at any altitude or azimuth
terrestrial	Pertaining to the Earth.
ammonia	A molecule composed of one nitrogen atom and three hydrogen atoms (NH3).
neutron	A neutral particle found in the nucleus of atoms heavier than hydrogen
satellite	A small body which orbits a larger one
bsf	Basics of Space Flight (this document).
bipolar transistor	A transistor that uses both positive and negative charge carriers.
edema	Swelling of a body part caused by an abnormal buildup of fluids.
silicon strip detectors	Detectors made of tiny strips of silicon, which create voltage pulses when traversed by charged particles, such as electrons or positrons.
radian	Unit of angular measurement equal to the angle at the center of a circle subtended by an arc equal in length to the radius
rns	GCF reliable network service.
incomplete combustion	A combustion reaction or process that does not convert all of the fuel's carbon and hydrogen into carbon dioxide and water, respectively
hcc	Hardness Critical Category
world surface/world sheet	The surface traced in space-time by an extended object such as a string
seismometer	An instrument that detects vibrations in the ground from distant earthquakes.
zenith	The point on the celestial sphere directly above the observer
pn11	Pioneer 11 spacecraft.
amorphous	Material without the regular, ordered structure of crystalline solids
conservative scattering	Scattering that occurs in the absence of absorption.
hall effect	When an electric current is passed through a conductor and a magnetic field is applied at right angles, a potential difference is produced between two opposite surfaces of the conductor
dose	The radiation energy absorbed-per unit mass of a material.
groin	The area where the thigh meets the hip.
isotherm	A contour line that corresponds to values measured at identical temperatures
gauge invariance	this would be better called `local phase-angle independence'
pio	JPL's Public Information Office.
periodic table	An arrangement of the elements according to increasing atomic number that shows relationships between element properties.
fixer	A chemical solution (acidic) which removes the unexposed and underdeveloped silver halide crystals from the film so it will not discolor or darken with age or exposure to light
period	Rows in the periodic table are called periods
uso	Ultra Stable Oscillator, in a spacecraft telecommunications subsystem.
adsorption	A process in which a layer of atoms or molecules of one substance forms on the surface of a solid or liquid
monochromatic	Of one wavelength or color.
gssr	Goldstone Solar System Radar, a technique which uses very high-power X and S-band transmitters at DSS 14 to illuminate solar system objects for imaging.
law	A theory of such wide and invariable application that its violation is thought to be impossible.
gregorian calendar	(a) Calendar established with the authority of the Roman Catholic Church by Pope Gregory XIII in 1582
z-number	See atomic number
tcp	Transmission Control Protocol
parallax	Change in the apparent position of objects when viewed from two widely separated positions.
volt	Unit of electric potential in the SI unit system
exposure or irradiation time	The time interval in a radiological examination within which x-rays are incident upon the body part under examination.
mean solar day	The mean length of time (24h00m00s) between two successive culminations of the Sun (i.e., the mean period from apparent noon to apparent noon)
methane	A colorless and odorless gas that belongs to the alkane series of the hydrocarbons.
h	Hour, 60 minutes of time.
relativity	(a) The theory of how motion and gravity affect the properties of time and space
adsorption	adhesion to a surface in an extremely thin (often monomolecular) layer
light-year	The distance travelled by light through space in one year
histiocytic lymphoma	The old Rappaport classification for the form of Non-Hodgkin's Lymphoma now known as large cell lymphoma.
launcher	Powered vehicle used to carry one or more satellites into space.
isochrones	Time-constant loci
power	work done or energy transferred per unit of time
superconductivity	The ability of certain materials to carry an electric current with zero electrical resistance.
three-phase ccd	A CCD construction in which three overlapping metal electrodes are used to define a pixel and effect the transfer of charge, in either direction along a column, by the charge-coupling method
capture	The absorption of one particle by another
stabilizer	A substance that makes a mixture more stable
ob association	A loose gathering of O and B stars that typically stretches over hundreds of light-years and contains a few dozen OB stars
binomial probability	The probability that a particular result will be obtained in a given number of trials
angstrom	A unit of length equal to 0.0000000001 (1 x 10-10) meters.
organelle	specialized cellular part analogous to an organ
std	Standard 34-m DSS, retired from DSN service.
nanometer	A unit of length equal to one billionth of a meter.
trophic level	level within a food chain in which all members are equally far removed from the primary food producers
11	Onboard Systems 12 -- Science Instruments 13 -- Navigation
fet	Field Effect Transistor
horizon	The maximum distance that an observer can see
4-kpc arm	A component of the Sagittarius arm with non-circular gas motions
bias	(a) A potential applied to an electrode in an electronic device to produce the desired characteristic
barn	(a) Symbol: b A unit of area defined as 10-28 square meter
magnetic moment	(a) The intrinsic spins of the electrons in an atom or ion, together with the motion of the electrons round the nucleus, give rise to a magnetic field around the atom
tumor burden	The amount of cancer cells that are present in the body.
arc minute	One-sixtieth of a degree on the sky.
wavenumber	The number of wave crests per unit distance
picometer	10-12 meter.
kilogram	The SI basic unit of mass (not of weight or of force)
gps	Global Positioning System
keplerian orbit	The orbit of a spherical particle of a finite mass around another spherical particle, also of finite mass, by virtue of the gravitational attraction between them
gui	Graphical user interface
photosynthesis	process by which light energy and chlorophyll manufacture carbohydrates out of carbon dioxide and water
interstellar square law	Decreasing as one over distance squared (1/r2), where r is the distance from the source
cw	continuous wave; a relative term of ancient lineage used to distinguish a simple wave with little or no modulation (e.g., a pure carrier (q.v.) or one simply keyed "on" and "off" as in manual radio telegraphy), vis-a-vis a highly complex, modulated wave (e.g., FM broadcasting)
target-film distance	The distance from the x-ray tube target (anode) to the film measured in inches or centimeters.
valence shell	The shell corresponding to the highest value of principal quantum number in the atom
coordinates	Quantities that provide references for locations in space and time
monodentate	A ligand that has only one atom that coordinates directly to the central atom in a complex
materialism	Belief that material objects and their interactions constitute the complete reality of all phenomena, including such seemingly insubstantial phenomena as thoughts and dreams
abundance	(a) The relative amount of a given element among others; for example, the abundance of oxygen in the Earth's crust is approximately 50% by weight
french guiana	French overseas territory on the north-east coast of the South American continent where the European Spaceport of Kourou is located.
spontaneous symmetry breaking	The breaking of an exact symmetry of the underlying laws of physics by the random formation of some object
crystal carbon lattice	The highly compressed and crystalline form of carbon that comprises a white dwarf star.
auto-catalysis	the ability of certain chemicals to enhance by their presence the rate of their own production in a sequence of chemical reactions
x-ray tube	A cathode ray tube that focuses energetic streams of electrons on a metal target, causing the metal to emit x-rays.
hydrosphere	aqueous envelope of Earth, including bodies of water and water vapor in the atmosphere hydrothermal vent - opening in the sea floor produced by the hot magmatic emanations that are rich in water Hz - see hertz
statistical mechanics	The area of physics that analyzes the behavior of a system with very many members, such as a gas with many individual molecules
avalanche	A process such as that in which a single ionization leads to a large number of ions
carboy	A very large bottle
gravitational wave	Ripple in the structure of space-time which may occur individually or as continuous radiation
rf	Radio frequency
edr	Experiment Data Record.
maxwell	The cgs unit of magnetic flux through 1 cm2 normal to a field of 1 gauss
inclination	The angular distance of the orbital plane from the plane of the planet's equator, stated in degrees.
ind	JPL's Interplanetary Network Directorate, formerly IPN-ISD.
rossby waves	Cyclonic convection waves in a rotating fluid
aurora australis	an aurora ocurring in the southern hemisphere of the Earth
fusion	(a) In nuclear physics, the combining of the atomic nuclei of lighter elements to form nuclei of a heavier element
antenna	The part of a radio telescope responsible for detecting an electromagnetic wave
17th century scientist	a scientist born between 1600 and 1700 AD
evaporate	To convert a liquid into a gas.
satellite	A body that orbits around a larger body.
tides	(a) A differential gravitational force
radian	The supplementary SI unit of angular measure, defined as the central angle of a circle whose subtended arc is equal to the radius of the circle
barnard's satellite	also known as Amalthea.
chandler period	The period of the variation of the celestial poles (about 416-433 days, with a peak at 428 days)
alpha process	Term used to describe the addition of a helium nucleus (4He) to existing nuclei with in a giant star to form heavier elements
amagat	A unit of molar volume at 0° C and a pressure of 1.0 atmosphere
fluence	The number of particles or photons or the amount of energy that enters an imaginary sphere of unit cross-sectional area.
meteor shower	A group of meteors which appear to radiate from the same part of the sky and which occur over a limited period of a few days or hours
metazoan	an animal whose body is composed of cells differentiated into tissues and organs and (usually) a digestive cavity
three-way	Coherent communications mode wherein a DSS receives a downlink whose frequency is based upon the frequency of an uplink provided by another DSS.
thin-screen model	A model in which Gaussian angular scattering is concentrated near one point along the path
bragg angle	Glancing angle between an incident X-ray beam and a given set of crystal planes for which the secondary X-radiation from the planes combines to give a single reflected beam
person	a human living or dead
ionosphere	that region of Earth's upper atmosphere having an appreciable abundance of electrons and charged atoms (ions), ranging from 50 to 500 miles above the ground
divalent cation	An ion with a charge of +2.
avogadro's number	(6.02 × 1023): The number of atoms in 12 grams of 12C; by extension, the number of atoms in a gram-atom (or the number of molecules in a mole) of any substance
solid	A solid is a relatively dense, rigid state of matter, with a definite volume and shape
observational selection	The tendency to record those objects or phenomena that are most readily observed with the available tools or techniques, and to overlook the others.
transition probability	The probability that a system in one energy state will undergo a transition into another
isophotes	Lines connecting points of equal light intensity
fe	Far Encounter phase of mission operations.
spar	System Performance Analysis Report
climatology	The study of climate – the prevailing atmospheric conditions of humidity, temperature, winds, etc.
tt&c	Telemetry Tracking & Control
native	Naturally occuring forms of precious metals, for example, native copper, native gold, and native silver
lhe	The symbol for liquid helium
chemotherapy	Treatment with anticancer drugs.
flux	A detector-independent measure of the brightness of a source.
momentum	The measure of the motion possessed by a body, the product of its mass and velocity.
uplink	Signal sent to a spacecraft.
x-ray generator	A device which supplies electrical power to the x-ray tube
hydrometer	An instrument for measuring the specific gravity of liquids
artifact	an object made by humans
interferometry	Experimental technique making use of an interferometer to measure a physical parameter.
distortion	Unequal magnification of different portions of body area being x-rayed.
kilo-	A prefix meaning 103
empiricism	An emphasis on sense data as a source of knowledge, in opposition to the rationalist belief that reasoning is superior to experience.
parent compound	chemical compound that is the basis for one or more derivatives
gravitational waves	Einsteinian distortions of the space-time medium predicted by general relativity theory (not yet directly detected as of March 2010)
sawtooth wave	A waveform generated electronically (such as the variation of voltage with time), having a uniform increase that regularly and rapidly drops to the initial value
methane	The simplest hydrocarbon molecule, made of one carbon and four hydrogen atoms (CH4)
period	Time interval between two consecutive and similar phases of a regularly occurring event
astronomical coordinates	The longitude and latitude of a point on the Earth relative to the geoid
advection	The transfer of matter such as water vapor or heat through the atmosphere as a result of horizontal movement of an air mass
clapeyron's equation	A fundamental relation between the temperature at which an inter-phase transition occurs, the change in heat content, and the change in volume
homogenous	A common misspelling of homogeneous.
allotropy	existence of an element in more than one form
richardson-lucy method	An image reconstruction algorithm
solvent extraction	Solvent extraction is a method for separating mixtures by exploiting differences in the solubilities of the components
carbonaceous compounds	Material containing carbon or carbon compounds.
cgpm	General Conference of Weights and Measures, Sevres France
fluctuations	(a) Spontaneous deviations of the macroscopic variables from a certain `reference' state, arising from the thermal motion and the interactions of the molecules
topical	Applied directly to the skin.
pyrolyser	An instrument that breaks complex molecules into constituents by using heat.
speed-of-light circle	see Velocity-of-Light Radius
rfi	Radio Frequency Interference.
irs	Infrared source
perihelion	Periapsis in solar orbit.
universe	The total celestial cosmos
albedo	(a) The ratio of the amount of light reflected from a surface to the amount of incident light
a index	A daily index of geomagnetic activity derived as the average of the eight 3-hourly a- indices in a UTC day.
granule	Convective cell in the solar photosphere
violent galaxy	A type of galaxy differentiated only recently
blue-green algae	any of a class of algae (a group of mainly aquatic, simple photosynthetic plants) whose chlorophyll is marked by bluish-green pigments
sievert	The SI unit of dose equivalent equal to the produce of a dose of one Gray, the quality factor, and any other applicable modifying factors
dkf	DSN keyword file, also known as KWF.
basis set	A set of mathematical functions that are combined to approximate the wavefunctions for electrons in atoms and molecules.
stem cells	Primitive cells found mostly in the bone marrow but also in the blood stream
ionization	The process of adding one or more electrons to, or removing one or more electrons from, atoms or molecules.
cat scan	see Computerized Tomography
meteoroid	(astronomy) any of the small solid extraterrestrial bodies that hits the earth's atmosphere.
intravenous	Within, or administered into, a vein.
nucleic acid	A polymer made of repeating nucleotides
voltaic pile	An early battery consisting of disks of dissimilar metals (usually zinc and copper) separated by moist paper or cloth soaked in an electrolyte solution.
alprazolam	A medication used to treat anxiety or insomnia .
symptoms	Physical signs of a disease.
physical object	Anything tangible having existence (living or nonliving)
illumination	Symbol: E A measure of the visible-radiation energy reaching a surface in unit time
abvd	A chemotherapy regimen commonly used to treat Hodgkin's Disease. The drugs used are Adriamycin, Bleomycin, Vinblastine, and Dacarbazine. Comprehensive Information.
neupogen	See Granulocyte Colony-Stimulating Factor (G-CSF)
thermal diffusion	A method of separating gas molecules of different masses by maintaining one part of the gas at a lower temperature than the other (i.e
set	As in going below the horizon, for the technical definition, please follow this link to the U.S
x-ray diffraction pattern	Interference patterns created by x-rays as they pass through a solid material
periselene	Periapsis in lunar orbit.
ipn-isd	(Obsolete
occam's razor	Any hypothesis should be shorn of all unnecessary assumptions; if two hypotheses fit the observations equally well, the one that makes the fewest assumptions should be chosen.
velocity space	The subspace of phase space whose coordinates are the velocities in each of the three directions of ordinary space
lymph	The almost colorless fluid that bathes body tissues and carries cells that help fight infection.
intrathecal	Into the spinal fluid.
refelectance	The ratio of reflected to incident radiation
target	Material at which electrons from the cathode in an x-ray tube are aimed in order to produce x-rays.
window	A term used to describe the spectral range within which the Earth's atmosphere is transparent to radiation (see Optical Window; Radio Window)
host computer	The main or master computer in an instrumentation system
mars	Fourth planet from the sun, a terrestrial planet.
ionizing radiation	Any radiation displacing electrons from atoms or molecules.
stripping	Stripping is a technique for removing volatile components in a mixture by bubbling a stream of an chemically unreactive gas (like nitrogen) through the sample, and then 'scrubbing' the nitrogen through a solution or solid adsorbent that can recover the volatile materials.
smooth space	A spatial region in which the fabric of space is flat or gently curved, with no pinches, ruptures, or creases of any kind
equilibrium	A condition of balance between the forces operating on or within a physical system, so that no accelerated motions exist among the parts of a system
great red spot	See Red Spot
substrate	A substance that is acted upon by an enzyme during a biochemical reaction.
ice	International Cometary Explorer spacecraft.
rydberg correction	See Quantum Defect
anode	A positive electrode, also referred to as a target, toward which electrons are accelerated from the cathode
specific heat	Ratio of the quantity of heat required to raise the temperature of a unit mass of a substance by a unit amount to that required to raise the temperature of an equal mass of water by the same amount
angstrom	(a) A unit that measures the wavelength of light and equals 0.00000001 of a centimeter
moonset	For technical definition, please follow this link to the U.S
individual	Any human being.
thermal energy	Energy associated with the motions of the molecules, atoms, or ions in a substance.
mm	millimeter (10-3 m).
long pulse	The ionizing dose resulting from neutron irradiation
emit	To throw or give off.
revolution	A rotation through a full circle, or 360 degrees.
x process	The unknown nucleosynthetic process that Burbidge, Burbidge, Fowler and Hoyle said had formed the light nuclei Deuterium, Lithium, Beryllium, and Boron
gds	Ground Data System, encompasses DSN, GCF, DSMS, and project data processing systems.
platelet	A blood cell that helps to control bleeding by inducing clotting
spectrophotometer	A spectrometer with associated equipment so designed that it furnishes the ratio or a function of the ratio of the radiant power of two beams as a function of spectral position.
astrophysics	The subset of astronomy that deals principally with the physics of stars, stellar systems, and interstellar material.
db	decibel; a unit of power ratio equal to 10 times the common logarithm of the ratio
epidemiology	The study of the causes, distribution, and control of disease in populations.
eclipse	The obscuration of a celestial body caused by its passage through the shadow cast by another body.
red blood cell count	Measurement of the number of red blood cells in a sample of blood.
covariance	According to the general theory of relativity, theories of nature must have the same mathematical form in all coordinate systems
centaur	A launcher; the rocket used to launch the Cassini-Huygens spacecraft.
keyhole	An area in the sky where an antenna cannot track a spacecraft because the required angular rates would be too high
amgen	A pharmaceutical company making drugs for the treatment of ailments caused by cancer treatment. Neupogen® (G-CSF) which stimulates the production of white blood cells is manufactured by Amgen.
dcd	Dual Command Decoder
isosteric	Having identical valence electron configurations.
synthetic element	element which cannot be found as a mineral deposit
k index	a 3-hourly, quasi-logarithmic local index of geomagnetic activity relative to an assumed quiet-day condition
work function	(W): The amount of energy needed to release an electron from the attraction of positive ions in a metal
gene	The part of DNA that is responsible for determining a person's characteristics and that carries information from old cells to new cells.
tmod	(Obsolete
watt	Unit of power in the SI unit system
alt	Altimetry data.
secular instability	Instability caused by the dissipation of energy
fibrilles	Striations or streaks which are observed to form whirls in the Solar chromosphere
orientation	Position in space relative to a reference point.
hydrocarbon	Molecule which contains only hydrogen and carbon
dscc	Deep Space Communications Complex, one of three DSN tracking sites at Goldstone, California; Madrid, Spain; and Canberra, Australia; spaced about equally around the Earth for continuous tracking of deep-space vehicles.
domoic acid	Domoic acid is a toxic amino acid produced by certain species of algae
carbon monoxide	A molecule consisting of one carbon and one oxygen atom (CO)
hga	High-Gain Antenna onboard a spacecraft.
az	Azimuth.
ubvri	Designations for parts of the optical waveband, isolated by means of special glass filters which eliminate the unwanted regions, and used for standard astronomical intensity measurements
bolometer	A kind of detector mainly used to measure infrared radiation
halo population	Old stars typical of those found in the halo of the Galaxy; also called Population II
gram	A metric unit of mass, equal to 1/1000 of a kilogram
doxorubicin	The generic name for Adriamycin, a chemotherapy drug commonly used to treat Hodgkin's disease.
q-branch	A set of lines in the spectra of molecules corresponding to changes in vibrational energy with none in rotational energy
ellipse	A plane curve in which the sum of the distances of each point along its periphery from two points - its "foci" - are equal.
turn-off point	The point on the H-R diagram at which stars turn off from the Main Sequence
starlink	A software environment and suite of programs for astronomical data analysis developed in the UK and supported by the Rutherford-Appleton Labs
tethys	Fourth satellite of Saturn, discovered by Cassini in 1684
barnard's loop	A huge nebular shell around the central portion of Orion
unstable equilibrium	Equilibrium such that if the system is disturbed a little, there is a tendency for it to move farther from its original position rather than to return
specific gravity	Ratio of the mass of a given volume of a substance to that of an equal volume of water
geometric isomer	Geometric isomers are molecules that have the same molecular formula and bond connections, but distinctly different shapes.
exosat satellite	European X-ray Observatory Satellite launched in May 1983 and operational until 1986
luminescence	(a) The emission of radiation from a substance in which the particles have absorbed energy and gone into excited states
stationary nonequilibrium state	time-independent state of a system subjected to fixed constraints
chemisorption	use of chemical forces to take up and hold onto something
amor	A class of Earth-crossing asteroid.
sum-over-histories	Probabilistic interpretation of a system's past, in which quantum indeterminacy is taken into account and the history is reconstructed in terms of each possible path and its relative likelihood.
monomer	simple chemical compound of relatively low molecular weight which can undergo polymerization
uniform vibration	The overall motion of a string in which it moves without changes in shape
segmented mirror	A large mirror construction technique in which many smaller elements are built and then actively controlled to conform to the shape of the required large mirror.
electrolytic cell	A device that uses electricity from an external source to drive a redox reaction.
if	Intermediate Frequency
orbital quantity	A quantity used for calculating orbits
ultraviolet light	Electromagnetic radiation of a wavelength slightly shorter than that of visible light
quantum leap	The disappearance of a subatomic particle - e.g., an electron - at one location and its simultaneous reappearance at another
proton rocket	Russia's largest operational launch vehicle
mile	The mile employed in this book is the statute mile, equal to 5,280 feet
joule dissipation	The heat produced when a current is passed through an electrically resisting medium
pam	Payload Assist Module upper stage.
cassini division	A gap in Saturn's rings that divides the outer set from the inner set of rings.
emulsion	The sensitive layer of photographic or x-ray film containing a silver compound in a layer of gelatin.
relapse	The return of symptoms and signs of a disease after a period of improvement.
dysphagia	Difficulty in swallowing.
curve of growth	The relation between the equivalent width of an absorption line and the number of atoms that produce it
sublimation	process of passing from gas to solid state (or vice versa) without becoming a liquid
hydromagnetics	See magnetohydrodynamics
open string	A type of string with two free ends.
descending node	The point at which an orbit crosses a reference plane (such as a planet's equatorial plane or the ecliptic plane) going south.
sun	(a) The star that Earth orbits
tsytovitch effect	An effect wherein the index of refraction of a medium is much less than unity so that the phase velocity of electromagnetic waves is greater than the speed of light in the medium
dsot	Data System Operations Team, part of the DSMS staff.
tree	Transient Radiation Effects on Electronics
dq white dwarf	carbon lines (atomic or molecular) present.
fungus	plant of the Thallophyta subkingdom, which lacks chlorophyll and ranges in form from a single cell to massed bodies, including yeasts, molds, and mushrooms
astronomy	Study of the space beyond the Earth and of its contents.
bwg	Beam waveguide 34-m DSS, the DSN's newest DSS design.
radar	Radio Detection and Ranging
transmittance	The ratio of radiant power transmitted by the sample to the radiant power incident on the sample.
proton	A positively-charged subatomic particle
families	(a) Organization of matter particles into three groups, with each group being known as a family
ln2	The symbol for Liquid Nitrogen
antiemetic	A drug that reduces or prevents nausea or vomiting
ion	(a) A charged particle consisting of an atom, or group of atoms, that has either lost or gained electrons
cytogenetics	identification of abnormal chromosomes in a cellular tissue sample.
w44	A radio source
mole	The SI unit of the amount of substance, defined as the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon 12 [14th CGPM 1971, Resolution 3]
froissart bound	If in a hadron-hadron collision the absorption is complete, then the interaction radius cannot increase faster than the logarithm of the energy
wavelength	The distance between between one point on a wave and the same point in the next cycle
satellite	A body that revolves around a larger body
acute	Sudden, rapid onset of disease or symptoms.
thermohaline convection	A type of hydrodynamic instability
asymmetry	A violation of symmetry
ferroin	A blood-red complex of Fe2+ ion with 1,10-phenanthroline, used as a redox indicator
gaussian year	The period associated with Kepler's third law with a = 1
cpu	Central Processing Unit The part of a digital computer responsible for interpreting and executing instructions
spectrum	A range of frequencies or wavelengths.
hypothesis	A scientific proposition that purports to explain a given set of phenomena; less comprehensive and less well established than a theory
atomic weight	Atomic weight is .the relative weight of the atom on the basis of oxygen as 16
ethane	A colorless and odorless gas that belongs to the alkane series of the hydrocarbons.
open space	A space of infinite volume and without any boundary (in the cosmological context)
fine structure	(a) Closely spaced lines seen at high resolution in a spectral line or band
geocentric	(a) Having the Earth at the centre
peptide	A short polymer made by linking together amino acid molecules.
free energy	Energy that is actually available to do useful work
glutamate	Ionic salts of glutamic acid used as flavor enhancers in many foods
quantum number	Indices that label quantized energy states
x-ray personnel	Individual legally allowed to use diagnostic x-rays on human beings
ccsds	Consultative Committee for Space Data Systems, developer of standards for spacecraft uplink and downlink, including packets.
frequency	A property of a wave that describes how many wave patterns or cycles pass by in a period of time
residual intensity	Ratio of correlated flux in the line to correlated flux in the continuum
ultraviolet light	band of electromagnetic radiation from about 40 to 4000 Å.
commutation relations	in quantum mechanics, if one has two operators A and B, then it is often the case that the action of the product operator AB is not the same as that of BA
trajectory	The curving path of a body in motion through space.
guaranteed time	Proportion of a science mission's operational time that is allocated to priority users such as the principal investigators of its science instruments.
burkitt's lymphoma	A type of Non-Hodgkin's lymphoma that most often occurs in young people between the ages of 12 and 30
kramers's opacity	The opacity of stellar material derived by Kramers, who in 1923 carried out theoretical calculations of stellar opacity as a function of chemical composition
multiplexing	A scheme for delivering many different measurements in one data stream
db	Decibel, an expression of ratio (usually that of power levels) in the form of log base 10
isomerization	A chemical change that involves a rearrangement of atoms and bonds within a molecule, without changing the molecular formula.
radiation therapy	Treatment with high-energy radiation from X-rays or other sources of radiation (like radioisotopes).
iso	International Standards Organization.
theory	A set of hypotheses and laws that have been well demonstrated as applying to a wide range of phenomena associated with a particular subject.
vesta	An asteroid 500 km in diameter (P = 1325 days, a = 2.361 AU, e = 0.09, i = 7°.1)
false color	The use of colors, instead of shades of grey, on a computer image display screen to represent different brightness levels and highlight very small differences in a dramatic way
nuclear fusion	A nuclear reaction in which two small atomic nuclei fuse to form a larger one
sar	Synthetic Aperture Radar
mct	Multiple Collateral Threat
lan	Local Area Network -- A means of interlinking computers
hydrolysis	A catch-all term for any reaction in which the water molecule is split.
retrograde motion	In a backwards direction; in astronomy this means in a direction corresponding to east-to-west.
s-wave	Secondary Wave: A seismic shear wave that moves transversely through Earth
lommel-seeliger surface	A surface with large-scale roughness where shadowing effects are important
stage	The extent to which lymphoma has spread from its original site to other parts of the body
ergodic motion	Motion by one or more particles which fills phase space with uniform density after a sufficiently long time
www	World-Wide Web.
inclination angle	The angle between the rotation axis of a planet and the perpendicular to the ecliptic plane.
bernoulli probability	See binomial probability
integrated rate law	Rate laws like d[A]/dt = -k[A] give instantaneous concentration changes
protein	A complex polymer made by linking together amino acid molecules
shield/shielding	Material which is interposed between a radiation source and an irradiated site for the purpose of minimizing the radiation hazard (used to prevent or reduce the passage of radiation).
patina	A thin layer of corrosion products with a distinctive coloration that forms on a metal surface exposed to air and water
special relativity	(a) Einstein's theory of time and space, formulated in 1905, which shows how measurements of length and time differ for observers in relative motion
conservative field	A field of force such that the work done on or by a body that is displaced in the field is independent of the path
cdscc	DSN's Canberra Deep Space Communications Complex in Australia.
accelerator	1
decaying orbit	An unstable orbit from which the orbiting object will gradually spiral into the body it is orbiting.
determinism	The doctrine that all events are the predictable effects of prior causes.
cytology	The study of cells, their origin, structure, function, and pathology.
entropy	tendency of systems to become more disordered (and thus more uniform) over time; also a measure of disorder
heat shield	A thick layer that protects from heat.
eps	Electrical Power System
clade	group of organisms all descended from a single common ancestor
van allen radiation belt	See Radiation belt (van Allen).
nova	A star that brightens suddenly and to an unprecedented degree, creating the impression that a new star has appeared where none was before
trillion	A thousand billion (1012) in American usage
liquid crystal	substances intermediate in their properties between liquids and crystals
photocurrent	A flow of excess charge carriers generated by ionizing radiation.
phase	The particular appearance of a body's state of illumination, such as the full or crescent phases of the Moon.
lth	LET Threshold
clinical trial	Research conducted with volunteer patients, usually to evaluate a new treatment under strictly controlled conditions
radiation belt	Two doughnut-shaped belts of charged particles interacting with Earth's magnetic field
effective theory	Each part of the physical world can be described by a sub-theory that applies over a certain distance scale or energy scale
vulcan	The name of a hypothetical planet at one time thought to exist between the Sun and Mercury
combination reaction	A reaction in which two or more substances are chemically bonded together to produce a product
celestial event	Event involving one or more celestial objects
calorimeter	A detector with a component that releases electricity when a photon of light passes through it
thomson scattering	The limit of Compton scattering at low energies
hermetic	Of or relating to Hermes Trismegistus, a mythical philosopher beloved of the Neoplatonists and usually identified with ancient Egypt
mos	Metal Oxide Semiconductor
crust	outer part of Earth, composed essentially of crystalline rocks
propulsion	Process by which something can be moved by producing a reaction with a force of thrust.
mr	Mars relay.
67p/churyumov-gerasimenko	Comet 67P/Churyumov-Gerasimenko was selected as the new target for ESA's Rosetta mission in May 2003.
hz	Hertz A unit of frequency equal to one cycle (or wave) per second
thermochemistry	The study of heat absorbed or released during chemical changes.
-time	A time scale in which there is no relative motion between two observers (cf
planck constant	The Planck constant, h, is a fundamental physical constant
kelvin scale	A temperature scale with the same divisions as the Celsius (centigrade) scale and with the zero point at 0° absolute
greenhouse effect	Retention and escalation of temperature beneath a mantle of clouds or denser atmosphere
bragg's law	If a beam of x-rays of wavelength is directed at a crystal with parallel crystal planes that are distance d apart, then the reflected x-rays from each plane undergo interference
helium-strong stars	B-type stars in which the helium lines are stronger than in normal stars
collapsed star	see Black Hole
tlm	DSN Telemetry data.
x-ray	The region of the electromagnetic spectrum with wavelengths in the range of 10-12 meters to 10-9 meters
et	Ephemeris time, a measurement of time defined by orbital motions
julian proleptic calendar	The calendric system employing the rules of the Julian calendar, but extended and applied to dates preceding the introduction of the Julian calendar itself
working distance	The distance between the front lens of the objective and the surface over the cover slip is called working distance (or free working distance), when the focus is adjusted to the uppermost specimen details right below the cover glass
cid	Charge Injection Device
homogeneity	(a) In cosmology, the property that any large volume of the universe looks the same as any other large volume
abiotic	Non-biological in origin.
gravity darkening	See von Zeipel's theorem
lan	Local area network for inter-computer communications.
symbiosis	intimate living together of two organisms (called symbionts) of different species, for mutual or one-sided benefit
ion	An atom or molecule which has one or more of its surrounding electrons separated from it and therefore carries a positive electric charge, or a free electron carrying a negative electrical charge.
meridional flow	Flow between the poles, or between the equator and the poles
fds law	see Fermi-Dirac-Sommerfeld Law
unified theory	Any theory that describes all four forces and all of matter within a single, all-encompassing framework.
flat	Subject to the rules of geometry codified by Euclid; a shape, like the surface of a perfectly smooth tabletop, and its higher-dimensional generalizations
monotonic	Either continuously increasing or decreasing
payload module	Some satellites are built in a modular way
adjuvant therapy	Anticancer drugs or hormones given after surgery and/or radiation to help prevent the cancer from recurring.
phase change	metamorphosis of a substance from one state to another, as from gas to liquid or from solid to gas
jpo	Joint Program Office
n	Neutron fluence in n/cm2; 1 MeV eq.
visible light	The portion of the electromagnetic spectrum corresponding to the visible colors, with wavelengths longer than ultraviolet light and shorter than infrared radiation.
energy	The capacity of a body or system to do work
month	The period of one complete synodic or sidereal revolution of the Moon around the Earth; also a calendrical unit that approximates the period of revolution
magnetosphere	The immediate region around a body with a magnetic field where particle behavior is controlled by that field.
lattice	A regular array of ions or atoms.
attenuation	The process by which an x-ray beam of radiation is reduced in intensity by absorption or scattering when passing through material.
hef	DSN's high-efficiency 34-m DSS, replaces STD DSSs.
hermitian matrix	A matrix which remains unchanged if each element is replaced by its complex conjugate and the rows and columns are interchanged
order-of-magnitude estimate	An approximate estimate of the magnitude of something, accurate to within a range of 10 times too big to 10 times too small
copernican principle	The principle that Earth is not the center of the Universe
occam's razor	(a) The notion that the simplest explanation of a problem is the preferred explanation, unless it is known to be wrong
pruritus	Itching (sometimes an unofficial "B" symptom of Hodgkin's Disease).
old thin disk	The older part of the thin-disk population, ranging in age from about 1 to 10 billion years
ecemp	Electron Caused Electromagnetic Pulse
focus	Point at which converging rays meet and at which a clearly defined image can be obtained.
faraday rotation	Rotation of the plane of polarization of linearly polarized radiation when the radiation passes through a plasma containing a magnetic field having a component in the direction of propagation
point of apoapsis	(astronomy) the point in an orbit farthest from the body being orbited.
seeing	in astronomy, this is the quality, not the act of observation; it refers to the atmospheric turbulence degrading an image and is measured by the smallest detail of the image that can be readily distinguished
volatile	Able to vaporize at relatively low temperature
isothermal	Having constant temperature.
kelvin contraction	The contraction of a star contemplated by Kelvin and Helmholtz as a consequence of a star's radiating its thermal energy
inverse beta-decay	The relatively rare process p + vbar → n + e+
coma	The cloud of diffuse material surrounding the nucleus of a comet.
photosynthesis	The chemical process by which green plants use solar energy to synthesize carbohydrates from carbon dioxide and water, releasing molecular oxygen as a byproduct.
cryostat	Container used to isolate thermally a fluid from its environment and maintain it at low temperatures.
cyanide process	A method for separating a metal from an ore
adiabatic index	The ratio of the fractional change in pressure to the fractional change in density as an element of fluid expands (or contracts) without exchange of heat with its surroundings
two-component model	A model of the solar wind which has two thermal components - electron and proton gases of differing temperatures
intensity	A measure of the rate of energy transfer by radiation
gravitational radius	The radius which an object should have in order that light emitted from its surface just ceases to escape from its surface
fermentation	A class of biochemical reactions that break down complex organic molecules (such as carbohydrates) into simpler materials (such as ethanol, carbon dioxide, and water)
ccb	Configuration Control Board
boundary condition	(a) Restriction on the limits of applicability of an equation
nasa	The National Aeronautics and Space Administration, founded in 1958 as the successor to the National Advisory Committee for Aeronautics.
ss	Sample Size
transient effects	Change in material properties that persist for a time shorter than or comparable to, the normal response time of the system of which the material is a part,
theory	A rationally coherent account of a wider range of phenomena than is customarily accounted for by a hypothesis.
naked eye object	a physical object visible to the unnaided human eye
erc	NASA's Educator Resource Centers.
valence state	state of electrical imbalance in an atom or molecule
electromagnetic spectrum	All the different colors of light, which is also called electromagnetic radiation
b ring	The middle of the three rings of Saturn that are easily seen in a small telescope
planisphere	a map showing half or more of the sphere of the heavens, indicating which part is visible at what hour from a given location.
electron shells	Zones in which the electrons in atoms reside
ob	Observatory phase in flyby mission operations encounter period.
gcf	Ground Communications Facilities, provides data and voice communications between JPL and the three DSCCs.
matrix	A rectangular array of numbers or algebraic quantities representing a system of entities related in a systematic manner
joule	(a) The SI unit of energy, work, or quantity of heat
illuminated	Describes a type of electromagnetic wave detector
reaction rate	The rate at which a chemical or nuclear reaction proceeds
eutectic	A mixture of two or more substances which has the lowest melting point.
z	Atomic Number
soap	A salt of a fatty acid
conjunction	A configuration in which two celestial bodies have their least apparent separation.
heliopause	The boundary theorized to be roughly circular or teardrop-shaped, marking the edge of the sun's influence, perhaps 100 AU from the sun.
existence theorems	these are the theorems that assert the existence of mathematical objects satisfying a specific set of axioms
palliative	Treatment designed to reduce the symptoms of a disease rather than to cure it.
apolune	Apoapsis in lunar orbit.
residue	1
siderophile element	element that tend to concentrate in metallic iron
fermi	(a) A unit of length equal to 10-13 cm
injection current	The current flowing in the load of a cable exposed to photon radiation
superconductivity	(a) A phenomenon occurring in some metals at very low temperatures, in which the resistance drops to zero and the metal shows many other anomalous properties
mass	A fundamental property of an object comprising a numerical measure of its inertia; the amount of matter in the object
characteristic curve	A type of input-output "curve" used to express the change in density with the change in radiation dose exposure of the photographic or x-ray film
nasal t-cell lymphoma	A subset of angiocentric lymphomas, it is treated with doxorubicin (adriamycin) based combination chemotherapy and is managed like diffuse large cell lymphoma.
shield/shielding	Usually made of lead which is dense and absorbs radiation easily
functional group	A substructure that imparts characteristic chemical behaviors to a molecule, for example, a carboxylic acid group.
nonpolar	Having a relatively even or symmetrical distribution of charge.
densitometer	An instrument used to measure film density which is degree of blackening of film by measuring the ratio of the light intensity incident on the film to the light intensity transmitted by the film.
flavor	(a) The term used to describe different quark types
cosmic rays	Relativistic elementary particles, such as electrons, protons or atomic nuclei, that exist throughout interstellar space.
galactic light	See diffuse galactic light
sfos	Space Flight Operations Schedule, product of SEGS.
mutation	A transformation of the gene which may be induced by radiation and may alter characteristics of the offspring.
ortho-spectrum	Spectrum of triplet (l = 1).
throughput	A measure of the efficiency of an optical system
fy	Fiscal year.
gain	The amplification factor
absolute temperature	(a) Temperature measured on the Kelvin scale: 0 Kelvin = -273.15° Celsius
humectant	A substance that absorbs or retains moisture, added to a product to keep it from drying out.
bexxar	A radiolabeled monoclonal antibody used in clinical trials as a treatment for B-cell Non-Hodgkin's Lymphoma. More Information.
vector meson	Also called the intermediate vector boson
law of definite proportions	When two pure substances react to form a compound, they do so in a definite proportion by mass
celestial pole	One of two points at which the Earth's axis of rotation, if extended, would intersect the celestial sphere.
quark	(a) Fundamental particle of which protons, neutrons and electrons are now thought perhaps to be made up
3 process	A nuclear reaction (3 4He 12C + + 7 MeV) by which helium is transformed into carbon
topology	(a) The branch of mathematics that treats the `large-scale' structure of curved spaces
trigonal pyramidal	A molecular shape that results when there are three bonds and one lone pair on the central atom in the molecule
interstellar	Between celestial objects; often refers to matter in space that is not a star, such as clouds of dust and gas.
unified theories	(a) In particle physics, any theory exposing relationships between seemingly disparate classes of particles
extravehicular	Outside the spacecraft; activity in space conducted by astronauts (EVA = extravehicular activity).
erythrocyte	The red blood cell that carries oxygen to the cells and carries carbon dioxide away from them.
solar wind	Flow of lightweight ions and electrons (which together comprise plasma) thrown from the sun.
medicare	A US federal medical insurance program for senior citizens and the disabled.
mesosphere	The part of Earth's atmosphere immediately above the stratosphere, where the temperature drops from about 270 K to 180 K.
nova	A star which suddenly increases in brightness by a factor of more than hundred
laser	The word laser stands for Light Amplification by Stimulated Emission of Radiation
megaflops	Millions of floating-point operations per second
wax	An ester formed from long-chain fatty acids and alcohols that is usually solid at room temperature.
drug resistance	The failure of (cancer) cells to respond to drugs (chemotherapy).
ha	Hardness Assurance
apheresis	Collection of peripheral blood cells, especially stem cells, by a device similar to a dialysis machine
lymph nodes	Small, bean-shaped organs located along the lymphatic system
angstrom	Unit of length convenient for measuring wavelengths of electromagnetic radiation
kytril	(Generic drug name granisetron) - an antiemetic (nausea suppression) drug commonly prescribed for chemotherapy-induced nausea
cancer	A general term for diseases that are characterized by uncontrolled, abnormal growth of cells. Lymphoma is a subset of cancers that originates in the lymph system.
streamline	(a) A line following the direction of the fluid in laminar or streamline flow
combination chemotherapy	The use of more than one drug to treat cancer. Some combinations are ABVD (Hodgkin's) or CHOP (NHL).
twilight	For technical definition, please follow this link to the U.S
side effect	Secondary effect caused by cancer treatment.
interleukin	A natural hormone-like substance produced by the body that activates the growth of certain types of lymphocytes.
circle	An ellipse possessing but one focus
cherenkov detector	Apparatus through which it is possible to observe the existence and velocity of high-speed particles important in experimental nuclear physics and in the study of cosmic radiation
sunspot	A relatively cool, dark region on the Sun's surface (photosphere) which is created by the Sun's magnetic field
julian calendar	(a) Calendar established by Julius Caesar in 46 BC, which overestimated the duration of the sidereal year by 11 minutes and 14 seconds
theory of everything	A "Theory of Everything" would not only describe how thing s work but also explain why things are the way they are
achromatic lens	Lens (or combination of lenses) that brings different wavelenghts within a ray of light to a single focus, thus overcoming chromatic aberration
translucent	Able to pass radiation, but with much deviation and/or absorption
aten	A class of Earth-crossing asteroid.
supermultiplet	A multiplet of multiplets
overtone	See harmonic overtone
solute	A substance dissolved in a solvent to make a solution.
cmc	Complex Monitor and Control, a subsystem at DSCCs.
durable power of attorney	The legal designation of a person responsible for managing another person's affairs if he/she becomes unable to do so
iras	Infrared Astronomical Satellite.
mantle cell lymphoma	An aggressive form of non-hodgkin's lymphoma
lowell's band	A dark border sometimes found on the Martian polar cap
terraform	The process of generating an Earth-like environment on celestial bodies that are currently inhospitable.
theory	(a) A rationally coherent account of a wider range of phenomena than is customarily accounted for by a hypothesis
isomer	(a) A molecule having the same number of atoms of each element as another molecule
bromine	A deep red, moderately reactive element belonging to the halogens
amplitude modulation	(AM) A type of modulation in which the amplitude of a carrier wave is modulated by an imposed signal, usually at audio frequency
chromosome	a gene-containing filamentous body found in cell nuclei
carbon black	A form of amorphous carbon (soot) produced by incomplete combustion of gas (or other organic matter)
wkb method	(Wentzel-Kramers-Brillouin) A method for obtaining an approximate solution to Schrödinger's equation
pharmacognosy	Identification, isolation, and characterization of biologically active substances in living things.
isoelectronic sequence	A sequence of ions which have the same number of electrons but different atomic numbers
granulation	A mottled cellular pattern visible on the Sun's photosphere
isoelectronic	Refers to a group of atoms or ions having the same number of electrons
fractal	A geometric figure in which a pattern is repeated ad infinitum on smaller and smaller scales
fine-tuning	A phrase meaning a highly constrained and implausible adjustment of the parameters of a theory
s/var	Survivability Vulnerability Analysis Report
psu	Pyrotechnic Switching Unit onboard a spacecraft.
orbital plane	(astronomy) the plane on which a body is orbiting.
civil twilight	For technical definition, please follow this link to the U.S
ecology	study of the relationship between organisms and their environment
insolation	Amount of radiation received from the Sun per unit area on the Earth's surface per unit time
fixer retention	The inadequate removal of fixer from the film by the water in the wash tank of the processor; causes eventual brown discoloration of the radiograph.
allotropy	The existence of a solid substance in different physical forms
spectrometer	An instrument with an entrance slit and one or more exit slits, with which measurements are made eigther by scanning the spectral range point by point or by simultaneous measuements at several spectral positions.
interference pattern	Wave pattern that emerges from the overlap and the intermingling of waves emitted from different locations
thomas-fermi theory	A theory of the energy of partially ionized matter in the limit of high density (see also Boltzmann-Saha Theory) [H76]
degree	A unit of angular size
ellipse	A closed plane curve generated in such a way that the sums of its distances from the two fixed points (the foci) is constant.
uranus	Seventh planet from the sun, a gas giant or Jovian planet.
virginis	Spica
oscillator strength	A measure of the probability that a transition represented by an electronic oscillator will occur
solar storm	Violent outburst of explosive activity on the Sun.
force quantity	Agency responsible for a change in a system
concave	Curving inward, away from the viewpoint
lennard-jones potential	An approximation of the interaction between two atoms or molecules
russell-vogt theorem	See Vogt-Russell theorem
time series	A graph showing how the radiation from an object varies over time
cruise phase	The phase of a spacecraft's journey needed to reach its target.
atmosphere	Mixture of gases and traces of dust, ices, and droplets gravitationally bound to a planet.
paradox	A self-contradictory proposition
velocity field	The velocities of a group of objects with different velocities at different positions of space
optics	The science of light
metagalaxy	A synonym for the Universe
photosynthesis	a biochemical process operating in green plants in which carbohydrates are formed under the influence of light with chlorophyl serving as a catalyst
ram	Random Access Memory.
thermal	Pertaining to heat.
fm	Femtometer (10-15 m)
slepton	The supersymmetric partner of any of the leptons.
upl	The DSN Uplink Tracking & Command subsystem.
angstrom	Unit to measure length, sometimes used to measure the wavelength of light
lambert's law	The intensity of radiation passing through a material decays exponentially with path length b.
geocentric cosmology	A model of the universe in which the earth is centrally located, and the Sun, planets, and stars revolve around the Earth.
nicad	Nickel-cadmium rechargable battery.
fdv	Functional Design Verification
theodolite	An optical instrument (using prisms and lenses) for measuring horizontal and vertical angles with great accuracy
van maanen's star	A white dwarf 4 pc distant; density 4 × 105 g cm-3
bottom	A flavor of quark
jacobi ellipsoid	Jacobi discovered that homogeneous, self-gravitating masses rotating uniformly and sufficiently rapidly can have the shape of triaxial ellipsoids
dcc	The DSN Downlink Channel Controller, one of which is in each DSN Downlink Channel, DC.
liquid	A state of matter that has a high density and is incompressible compared to a gas
cathode	A negative electrode; electrode in the x-ray tube from which electrons are emitted
pole	Usually the coldest regions on a planet, being the areas around an axis through the planet perpendicular to the plane of rotation about the Sun.
hawg	Hardness Assurance Working Group
spallation	The process in which small quantities of rock near the surface around a meteorite impact are ejected at high speed with only slight impact shattering.
activation energy	amount of energy needed to initiate a reaction
co-moving coordinates	(a) A set of coordinates which do not change in an expanding (or otherwise moving) medium
temperature	Physical parameter characterising the thermal state of a body
plasma cell	An antibody producing, mature B cell found in lymphoid tissue.
dna	deoxyribonucleic acid; the molecule that is the basis of heredity in many organisms
glycoprotein	conjugated protein in which the nonprotein group is a carbohydrate
bose-einstein nucleus	Nucleus of even A-number (i.e., those with integral spin) (cf
rf	Radio Frequency.
cavitation	The formation of small cavities in a liquid, caused by a reduction in fluid pressure
ensemble	A hypothetical group of many universes of varying properties
hospice	A program designed for caring for terminally ill patients and their families.
julian year	A period of 365.25 days
o	Spectral type for the hottest blue stars, even hotter than B-type stars
conservative system	(a) A system in which total energy is conserved in time, and the evolution of the observable properties is indifferent with respect to the direction of time
eros	A small asteroid, No
lorentz contraction	(a) Diminution in the observed length of an object along the axis of its motion, as perceived by an external observer who does not share its velocity
magnetic pressure	The pressure exerted by a magnetic field on the material that contains the field
strange	A flavor of quark
source-to-image distance	The distance measured along the central ray from the center of the front surface of the source (x-ray focal spot to the surface of the irradiated object or patient.
thermoelectron	An electron emitted by a very hot object.
reaction rate	A reaction rate is the speed at which reactants are converted into products in a chemical reaction
ideal solution	All molecules in an "ideal solution" interact in exactly the same way; the solvent-solvent, solvent-solute, and solute-solute intermolecular forces are all equivalent
sco	A system with at least five components which during the 1970s is undergoing a series of occultations by the Moon and by Jupiter
h-magnitude	The magnitude derived from infrared observations at 1.6 microns
ionized gas	A superheated gas partially or totally composed of ions.
periodic trend	A regular variation in element properties with increasing atomic number that is ultimately due to regular variations in atomic structure.
rads	The dose equivalent in rems is equal to the absorbed dose in ____ multiplied by the quality factor (1 rem - 0.01 Sievert).
isotropy	Having the same value of some physical property (e.g., density) when measured in any direction.
organochromic indicators	Colored organic compounds that change color when they chelate different metals
ellipse	A plane curve in which the sum of the distances of each point along its periphery from two points - its "foci" - are equal
naked singularity	A singularity that will be visible and communicable to the outside world.
strong base	A strong base is an base that completely dissociates into ions in solution
dosimeter	An instrument to detect and measure accumulated radiation dose (exposure).
of	Peculiar O stars in which emission features at 4634-4641 from N III and 4686 from He II are present
tumor board	A group of specialists who meet regularly to discuss management of individuals who have cancer.
vector boson	Force-carrying particles of nature
injection	use of a syringe and needle to deliver medications to the body (also called a "shot").
gray atmosphere	A model atmosphere in which the continuous absorption coefficient is assumed to be independent of frequency
ozone layer	A layer in the lower part of Earth's stratosphere (about 20-60 km above sea level) where the greatest concentration of ozone (03) appears
pulminary angiocentric b-cell lymphoma	Formerly called lymphomatoid granulomatosis, it is a condition that when malignant is treated with doxorubicin (Adriamycin) based combination chemotherapy and is treated like diffuse large cell lymphoma.
photonics	The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon for a range of applications ranging from detection to laser energy production to communications and information processing.
gastrointestinal	having to do with the digestive tract, which includes the mouth, esophagus, stomach, and intestines.
bar	(a) The absolute cgs unit of pressure equal to 106 dyn cm-2
ir	Infrared
mct	Mission Control Team, JPL Section 368 mission execution real-time operations.
colony-stimulating factor	A treatment agent used to stimulate the production of certain blood cells in the bone marrow
f layers	Two layers in the Earth's ionosphere (F1 and F2 at about 200 and 300 km, respectively) immediately above the E layer
wave zone	The field of a pulsar beyond the velocity-of-light radius
resolution capability	Minimum spacing of 2 wavelengths separable by Resolving power a grating, proportional to the grating area and inversely proportional to the wavelength.
solar neutral region	A region where the magnetic field strength approaches zero
abrasive	A very hard, brittle, heat-resistant substance that is used to grind the edges or rough surfaces of an object
xenobiotic	A substance which is not normally found in a living thing.
chemical	1 of or pertaining to chemistry
channel	In telemetry, one particular measurement to which changing values may be assigned
separation	place, line, or point of parting
physics	The study of matter and energy, and the forces and fields by which they interact in space and time.
planet	An astronomical body with enough mass for its gravity to make it spherical but not enough to generate nuclear energy
lymphoblastic lymphoma	A very aggressive non-hodgkin's lymphoma often occurring in younger patients
monte carlo method	A trial-and-error technique used on computers to solve complex problems
aberrations	Effects associated with the performance of optical components which give rise to imperfect optical images
turbulent flow	Fluid flow in which the speed at any point varies rapidly in magnitude and direction
amorphous	Denoting a solid that has no crystalline structure; i.e
neutral	1
leap year	Every fourth year, in which a 366th day is added since the Earth's revolution takes 365 days 5 hr 49 min.
order of magnitude	A factor of ten
sperm banking	Freezing sperm for future use
absorbed dose	Dose equivalent delivered per unit of time.
polymerization	process of forming long molecules (polymers) out of small units (monomers)
stereochemistry	Stereochemistry is the study of how the properties of a compound are affected by the spatial positions of groups within its molecules
order of magnitude	A factor or “power” of ten
hap	Hardness Assurance Program
charge number	see Atomic Number
librations	Variations in the orientation of the Moon's surface with respect to an observer on the Earth
interferon	A natural substance produced by the body in response to a virus
follicle	A cluster of cells.
azeotropic mixture	Aseotrope: A mixture of two liquids that boils without any change in composition
catheter	A flexible tube inserted into the body to transport fluids into or out of the body.
billion	In the U.S., 109
developer replenishment	Used to maintained the proper alkalinity, chemical activity, and level of solution in the developer tank.
mantle	layer of Earth that lies below the lithosphere and above the core
mach number	The ratio of the speed of a fluid to the speed of sound in that fluid
wimp	A very Weakly Interacting relatively Massive elementary Particle
attenuation	(a) The reduction of intensity of a radiation as it passes through a medium
renormalization	(a) The mathematical process which ensures that the basic quantities in quantum field theory (e.g
focal plane	Axis or geometric plane where incoming light is focused by the telescope.
free	Not bound to a nucleus
nausea	Feeling sick or wanting to vomit, possibly with dizziness or symptoms. Some chemotherapy combinations can cause nausea for up to several days - this can be lessened by taking antiemetic drugs.
speed factor	With intensifying screens, the __________ is defined as the ratio of the radiation dose (exposure) without screens to the radiation dose (exposure) required with screens to get the same degree of blackening of x-ray films.
einstein cosmological constant	The value of a supposed repulsion force that would contribute to the expansion of the Universe
topocentric	With reference to, or pertaining to, a point on the surface of the Earth, usually with reference to a coordinate system
bone marrow harvest	The removal and collection of bone marrow, usually done prior to a bone marrow transplant, but sometimes done as a preventative measure in case of relapse.
undifferentiated	Cells that lack a specialized structure and function.
modulation	The process of modifying a radio frequency by shifting its phase, frequency, or amplitude to carry information.
encounter	see Gravitational Encounter
observational cosmology	The application of observational data to the study of the Universe as a whole
magnetic monopole	A magnet with an isolated north (or south) pole, rather than a pair of equal-strength north and south poles, as in conventional magnets
radiation pressure	The transfer of momentum by electromagnetic radiation incident on a surface: prad = (4/3)σT4 / c.
astrolabe	(a) Ancient Arabic and medieval alt-azimuth device comprising two or more flat, metal, calibrated discs, attached so both or all could rotate independently
scholastics	Adherents to the philosophy and cosmology of Aristotle
mgso	(Obsolete
cbc	Complete blood count - see Blood Count.
superphylum	taxonomic category lying between a kingdom and a phylum
dosimeter	device that measures radiation dose.
gamma ray	Electromagnetic radiation with a wavelength less than about 1 Å (10-10 m); blends from the "hard" X-ray region
methane	A colourless and odourless gas that belongs to the alkane series of the hydrocarbons.
escape velocity	(a) Speed an object must attain in order to free itself from returning to the parent body under the effects of gravity
dyne	A unit of force equal to the force required to accelerate a 1-g mass 1 cm per second per second
four-wave mixing	this is the combination of three optical waves to generate a fourth
string coupling constant	A (positive) number that governs how likely it is for a given string to split apart into two strings or for two strings to join together into one-the basic processes in string theory
uvby system	A four-color, intermediate-bandwidth, photometric systemdevised by Strömgren consisting of measures in the ultraviolet, violet, blue, and yellow regions of the spectrum
thermodynamics	(a) The study of the behavior of heat (and, by implication, other forms of energy) in changing systems
entropy	(a) A thermodynamic property of a macroscopic body which corresponds intuitively to the degree of disorder
light time	The amount of time it takes light or radio signals to travel a certain distance at light speed.
state space	the mathematical space whose points represent the states of a physical system
microprocessor	A very large silicon integrated circuit with essentially all the functions of a computer on a single chip
solid	a high density collection of particle which do not move relative to one another (except for thermal oscillations)
kelvin	The kelvin is the fundamental unit of temperature in the SI system
clarke orbit	Geostationary orbit.
exponential	A process that changes at an accelerating rate, for example with a constant doubling time.
alopecia	Loss of hair, be it on the head or all over the body
virgo a	A strong radio source
apselene	Apoapsis in lunar orbit.
eutectic mixture	A mixture of two or more substances with melting point lower than that for any other mixture of the same substances.
cryogenic	Relating to processes at extremely low temperatures or to the technology used to produce such temperatures.
atom	(a) The smallest component of matter that retains its chemical properties
gray	The SI unit of absorbed dose equal to an energy deposition of 1 joule/kg = 10,000 ergs/gm (1__-100rads).
astronomical twilight	The period from sunset to the time that the Sun is 18° below the horizon; or the corresponding period before sunrise
faculae	Bright regions of the photosphere seen in white light, visible only near the limb of the Sun.
scet	Spacecraft Event Time, equal to ERT minus OWLT.
valence	The number of hydrogen atoms that typically bond to an atom of an element
cd-rom	Compact Disk - Read Only Memory A computer data storage technology
satellite elongation	The geocentric angle between a satellite and its primary, measured in the plane of the satellite, planet and Earth
allochthonous	Material formed or introduced from somewhere other than the place it is presently found
nrz	Non-return to zero
spectral lines	Molecules (and individual atoms) can exist in different energy states
spherical aberration	Image defect caused by a mismatch in the shapes of the reflecting surfaces of the primary and secondary mirrors
unsaturated compound	An organic compound with molecules containing one or more double bonds.
center of mass	point where entire mass of a body can be considered concentrated
calendar	A system of reckoning time in which days are enumerated according to their position in cyclic patterns
conservation of energy	The total energy of a system (including kinetic energy and gravitational energy) is conserved and does not vary
string theory	Theory that subatomic particles actually have extension along one axis, and that their properties are determined by the arrangement and vibration of the strings.
mos	Metal Oxide Semiconductor -- A construction used to fabricate microelectronic components
eccentricity	The distance between the foci of an ellipse divided by the major axis.
eddington approximation	An approximation used in the study of radiative transfer
sense	One of two opposite directions describable by the motion of a point, line, or surface
mare	An area on the moon that appears darker and smoother than its surroundings
nmc	Network Monitor and Control subsystem in DSN.
trc	NASA's Teacher Resource Centers
chirality	An expression of the basic handedness of nature
bot	Beginning Of Track, used in DSN operations.
eddy currents	Induced currents set up in a conductor by a changing magnetic field
optical fibre	A long, thin strand of glass capable of excellent transmission of light over large distances.
liquid	a high density cohesive collection of particle which move relative to one another and which has short range order
diffuse galactic emission	Non-point source gamma-ray emission from the plane of the galaxy
inclination	(astronomy) the angle between the plane of the orbit and the plane of the ecliptic stated in degrees.
kernel	The set of points mapped into zero
g	Gram, a thousandth of the metric standard unit of mass (see kg)
ssi	Space Services, Inc., Houston, manufacturers of the Conestoga launch vehicle.
si	The International System of Units (metric system)
science	(a) Systematic study of Nature, based upon the presumption that the Universe is based upon rationally intelligible principles and that its behavior can therefore be predicted by subjecting observational data to logical analysis
rover	A small remote-controlled vehicle for exploring the terrain close to a lander situated on a planetary surface.
inflaton	The name given to whatever fields are responsible for driving inflation
antigen	A cell marker produced by all cell types. Antigens help the body's immune system identify cells. The immune system uses antibodies to bind to the antigens in order to mark the cells for removal.
heisenberg model	A model of magnetic systems in which each magnetic atom has a spin which is free to point in any direction in space
strong-weak duality	Situation in which a strongly coupled theory is dual-physically identical-to a different, weakly coupled theory
warp	The deviation from flatness in the outer Galactic disk
icrs	International Celestial Reference System
meteorite	A fragment of rock that survives its fall to Earth from space
k star	Stars of spectral type K are cool, orange to red stars with surface temperatures of about 3600-5000 K
sbb barred spiral	Barred spiral galaxy with arms wound around the nucleus
protein	complex polymer built of amino acids that contains the elements carbon, hydrogen, nitrogen, oxygen, sometimes sulfur, and occasionally others such as phosphorus and iron
medicinal chemistry	A branch of chemistry concerned with the discovery, design, synthesis, and investigation of biologically active compounds and reactions that these compounds undergo in living things.
rv tau variables	Periodic variables with periods 60-100 days, and of spectral types G and K
staging	Determining the stage of the lymphoma
parabolic	A mirror whose surface is figured to the shape of a paraboloid, a particular form of open curve.
sequencer	That part of an electronic system responsible for the accurate phasing of time-critical events such as CCD clocking and readout
chemical equation	A compact notation for describing a chemical change
sc	Steering Committee.
b cell	A type of lymphocyte (a specific type of white blood cell)
prebiotic	Related to the period before life appears on a planet.
phenol	A group or molecule containing a benzene ring that has a hydroxyl group substituted for a ring hydrogen.
diaphragm	The thin muscle below the lungs and heart that separates the chest from the abdomen.
nmos	N-channel MOS
colorimetry	A method for chemical analysis that relates color intensity to the concentration of analyte.
exobiology	The study of evidence relevant to life on other worlds (synonymous with astrobiology).
methane	Gaseous hydrogen compound, one of the alkanes, in which every carbon atom is surrounded by four hydrogen atoms
lipid	A diverse group of organic molecules that contain long hydrocarbon chains or rings and are hydrophobic
awaruite	Ni-rich Fe metal, Ni3Fe, similar to taenite found in minor amounts in CV chondrites.
chemistry	The study of matter and its transformations
electronvolt	Unit of energy defined as the energy acquired by an electron in falling through a potential difference of one volt
kennelly-heaviside layer	Former name for the D and E layers (q.v.)
motion	Process of passing through space or changing position
voyager satellite	The name of two NASA spacecraft designed to study the outer planets (Jupiter, Saturn, Uranus and Neptune) of our Solar System.
subspace	a subset of a vector space which is closed under the operations of vector addition and scalar multiplication
granulocyte	A type of white blood cell that fights bacterial infection or foreign substances. They congregate around, engulf, and destroy the offending object in a process called phagocytosis. (A granulocyte is also called a neutrophil).
extraction	A technique for separating components in a mixture that have different solubilities
avogadro's number	Number of atoms, molecules, ions, etc
apollo	A class of Earth-crossing asteroid.
nm	Nautical Mile, equal to the distance spanned by one minute of arc in latitude, 1.852 km.
darwin mission	The Darwin mission is an ESA scientific mission currently under study
bessel equation	A linear second-order differential equation, the solutions to which are expressible in mathematical functions known as Bessel functions
pdt	Pacific Daylight Time.
vibrational energy	Motion of the pair of nuclei in a diatomic molecule along the direction of the internuclear axis (cf
pipe-line	Analysis and processing of scientific data in a sequential manner.
density	An object's mass divided by its volume
anisotropy	The characteristic of being dependent upon direction
indolent	Slow growing
nasa	National Aeronautics and Space Administration.
eucaryote	organism composed of one or more cells with clearly formed nuclei
helmholtz contraction	See Kelvin-Helmholtz contraction
thrusters	Small reaction engines on a spacecraft that can provide thrust used to control its orbit, orientation and attitude.
distortion	A general term denoting the quantity/amount of radiation or energy absorbed per unit mass
tropical year	The interval of time between two successive vernal equinoxes
sputnik 1	First artificial Earth satellite, launched by the Soviet Union on 4 October 1957
sunset	For technical definition, please follow this link to the U.S
photochemistry	The study of the effects of light on chemical reactions.
empowerment	Having the right to make one's own choices and having the ability to act on them.
characteristic value	see Eigenvalue
flocculus	see Plage [H76]
mass	The quantitative property of an object due to the matter it contains
standard treatment	Treatment that has been proven effective and is commonly used.
aerosol collector	An instrument that collects aerosols and analyzes their composition.
stress	When a system of opposing forces acts on a body the material is subject to some form of stress
drug	A biologically active compound or mixture used to cure, prevent, or detect disease, to control biological processes, or to alter mental state.
o ceti	see Mira
anaerobic	occurring in the absence of free oxygen
blood count	A routine test to determine the amount of white blood cells, red blood cells, and platelets in a sample of blood
correlation length	the correlation length gives a measure of the typical distance over which the fluctuations of one microscopic variable are correlated with the fluctuations of another
biconvex	Describing a lens with two convex faces
sirtf	Space Infrared Telescope Facility.
ion	An atom or molecule that has acquired a charge by either gaining or losing electrons
x-band	A radio band at a wavelength of 3.7 cm (8085 MHz)
science	Systematic study of Nature, based upon the presumption that the universe is based upon rationally intelligible principles and that its behavior can therefore be predicted by subjecting observational data to logical analysis.
g	Universal Constant of Gravitation
world point	see Event
topologically distinct	Two shapes that cannot be deformed into one another without tearing their structure in some manner
coherence	The existence of a correlation (statistical or temporal) between the phases of two or more waves
magnetic field	Region around a body in which a magnetic force is detected
visibility	Periods at which a celestial object, either natural or artificial, is visible from a point on Earth.
heat capacity	Also known also as thermal capacity
torsional wave	A wave motion in which the vibrations in the medium are rotatory simple harmonic motions around the direction of energy transfer
vector translation	The small theoretical precession of the axis of an orbiting body due to the gravitational influence of its primary
spectrum	A plot of the intensity of light as a function of frequencies; the distribution of wavelengths and frequencies.
gene therapy	The use of genes to treat cancer and other diseases.
half-life	(a) The time it takes for half of a given quantity of radioactive material to decay
rtvm	Requirements Verification Tracking Matrix
latitude	Circles in parallel planes to that of the equator defining north-south measurements, also called parallels.
natural selection	The mechanism of biological evolution
heliarc	A process of joining two metals using an electric arc in an atmosphere of a noble gas
orbit acquisition	Reception of the telemetry containing the information about the orbital parameters of the spacecraft.
ionization	The process whereby one or more electrons is removed from a neutral atom by the action of radiation (the conversion of atoms to ions).
surface tension	The work required to expand the surface of a liquid by unit area.
configuration	(a) The arrangement of electrons in shells around the nucleus of an atom
stereoisomer	Molecules with the same atoms and bond structure, but different three dimensional arrangements of atoms
bib	Blocked Impurity Band
exoplanet	Extrasolar planet
recombination	(a) The capture of an electron by a positive ion
thought experiment	An experiment that cannot be or is not carried out in practice, but can, given sufficient imagination and rigor, be reasoned through by thought and intuition alone
quick-look analysis	Initial examination of scientific data before further processing and investigation.
clay	earthy material, composed mainly of hydrous aluminum silicates and other minerals, which is plastic when moist but hard when fired
major axis	The maximum diameter of an ellipse.
quiescent prominence	A relatively pacific prominence which may last for months.
enzyme	Protein or protein-based molecules that speed up chemical reactions occurring in living things
convolution	A mathematical combination of two functions which involves multiplying the value of one function at a given point with the value of another function, the weighting function, for a displacement from that point and then integrating over all such displacements
kelvin	A temperature scale which measures an object's temperature above absolute zero, the theoretical coldest possible temperature
inflationary universe	A model of the early evolution of the Universe involving its exponential expansion
radiation	The energy carried by waves or particles
holmium	A soft malleable silvery element of the lanthanoid series of metals
interferometer	Measurement device in which a beam of electromagnetic radiation is split and subsequently recombined after travelling different pathlengths so that the beams interfere and produce an interference pattern
pcb	Parts Control Board
micro-	A prefix meaning 10-6
fm	Frequency modulation.
nucleotide base	A heterocyclic nitrogen-containing base that is a constituent of nucleotides
nitrogen	A chemical element, symbol N, with atomic number 14; under normal conditions it is a diatomic gas (N2)
element symbol	An international abbreviation for element names, usually consisting of the first one or two distinctive letters in element name
nocc	DSN Network Operations Control Center at JPL.
median	Literally the middle value in a sequence of values arranged in increasing size order
constant of precession	see Precession of the Equinoxes
subatomic particles	Particles which are smaller than an atom
planckian spectrum	Blackbody energy spectrum according to Planck's radiation law.
tauri	Also know as Aldebaran
argon	A chemical element, (symbol Ar, atomic number 18).
deep space network	NASA network of radio telescopes used to communicate with spacecraft operating far from the Earth
fabry-perot interferometer	(a) A type of interferometer wherein the beam of light is passed through a series of pairs of partly reflecting surfaces set at various angles to it and spaced at certain prechosen numbers of the wavelength to be examined
srd	Systems Requirements Document
jaundice	A yellowing of the skin and whites of the eyes
eti	extraterrestrial intelligence; also used to signify extraterrestrial intelligent species
flux unit	(a) Unit of flux density
nomenclature	A system for naming things
half-energy width	The angle within which half of the electromagnetic radiation (e.g
solar eclipse	An eclipse in which the Earth passes through the shadow cast by the Moon
plasma	Electrically conductive fourth state of matter (other than solid, liquid, or gas), consisting of ions and electrons.
critical speed	In fluid flow, the speed at which the behavior of the fluid switches from that of laminar flow to that of turbulent flow or vice versa
leakage radiation	Means all radiation coming from within the x-ray tube housing except the useful beam.
antiparticle	For every known type of particle, there exists an antiparticle with exactly the same mass, but with the opposite electric charge
voyager	(a) Pair of unmanned American spacecraft launched in 1977 on missions to Jupiter, Saturn, and beyond
kwf	Keyword file of events listing DSN station activity
thermal gradient	The rate at which the temperature changes with position.
achromat	An achromatic lens
nucleosynthesis	(astronomy) the cosmic synthesis of atoms more complex than the hydrogen atom.
cit	California Institute of Technology, Caltech.
root mean square	The square root of the mean square value of a set of numbers
ylem	Primordial state of matter - neutrons and their decay products (protons and electrons) - before the Big Bang
isochoric	Constant volume
mucositis	Inflammation of the mucus membranes (like the mouth) that causes pain, soreness, and/or excessive mucus production.
fechner's law	The intensity of a sensation increases as the logarithm of the stimulus
infrared	The region of the electromagnetic spectrum with wavelengths in the range of 2.5 x 10-6 meters to 7 x 10-7 meters
galactic cluster	See open cluster
juno	An asteroid 250 km in diameter (P = 1,594 days; a = 2.67 AU: e = 0.256; i = 13°.0) with a relatively large albedo (0.2)
height	Elevation above ground or distance upwards from a given level (especially sea level) to a fixed point
sunrise	For technical definition, please follow this link to the U.S
n	North.
thrombocyte	A blood cell that helps to control bleeding by inducing clotting
thermal energy	energy an object possesses by virtue of its temperature
scattering matrix	The S-matrix relates the incoming and out-going states of elementary particles during interactions and scattering experiments
geosynchronous	A direct, circular, low inclination orbit about the Earth having a period of 23 hours 56 minutes 4 seconds.
magma	molten matter under Earth's crust, from which igneous rock is formed
inertia	The tendency of a body to resist acceleration; the tendency of a body at rest to remain at rest or of a body in straight line motion to stay in motion in a straight line unless acted on by an outside force
intensifying screens	Devices which increase the brightness of the image produced by the action of x-rays upon a phosphor.
radiation	Used as a synonym for electromagnetic radiation.
night sweats	Profuse sweating during the night.
hormone	A molecule produced by endocrine glands that controls specific biological processes like growth and metabolism.
peripheral neuropathy	Numbness, tingling, burning, and/or weakness in the extremities (usually hands and/or feet). The chemotherapy drugs vinblastine (Hodgkin's) and vincristine (used for some NHLs) can cause varying degrees of peripheral neuropathy. More on the Peripheral Neuropathy page.
cmd	Color-Magnitude diagram [BFM02]
stratosphere	The region of Earth's atmosphere immediately above the troposphere
packet	A quantity of data used as the basis for multiplexing, for example in accordance with CCSDS.
si units	see International System of Units
mass	A measure of the total amount of material in a body
early-type emission stars	see Be Stars
bohrium	A synthetic radioactive element first detected by bombarding a bismuth target with chromium nuclei
shear	A stress applied to a body in the plane of one of its faces
gray	The S1 unit of absorbed dose.
k	Kelvin, the SI base unit of thermodynamic temperature.
phase boundary	A phase boundary is a surface where two samples of matter with different properties are in contact
k	A quantum number which refers to the component of angular momentum around a molecule's axis of symmetry
artifact	Any density or mark on a radiograph that is caused by something not belonging to the part of being x-rayed.
orbifold	A particular space used as a candidate for the compactified space of superstring theory
twta	Traveling Wave Tube Amplifier, downlink power amplifier in a spacecraft telecommunications subsystem, the final stage of amplification for downlink (same unit as TWT).
condensation	from gas to liquid or from gas to solid
gamma-ray burst	Brief intense gamma-ray emission from an unknown source.
latchup	Regenerative device action in transistors or circuits in which an undesirable stable condition is obtained.
fatigue	a lack of energy, general tiredness.
bunsen burner	A gas burner with adjustable air intake, commonly used in laboratories.
ehz	ExaHertz (1018 Hz)
charge transfer	The movement of charge within a material or from one 'material to another due to the interaction of high energy nuclear radiation with the material.
regression	Reduction in symptoms or disease process.
phase	The angular distance between peaks or troughs of two waveforms of similar frequency.
servicing mission	Auxiliary mission to have astronauts perform repairs and upgrades to satellite equipment in space.
monocytes	A type of leukocyte (white blood cell) that defends the body against bacterial infections. They also ingest aging and degenerating blood cells.
systems engineering review	A review which verifies that the systems engineering (design and construction) of a spacecraft corresponds to the requirements as contained in the design drawings.
light speed	299,792 km per second, the constant c.
particle	A fundamental constituent of matter
molecule	The smallest unit of a chemical compound
kinematic relativity	Theory proposed by Edward Milne as a viable alternative to Einstein's general theory of relativity, and based generally on kinematics (the science of pure motion, without reference to matter or force), from which Milne successfully derived new systems of dynamics and electrodynamics
uv stars	see Ultraviolet Stars.
solar mass	A unit of mass equivalent to the mass of the Sun
rtlt	Round-Trip Light Time, elapsed time roughly equal to 2 x OWLT.
pharmacology	The study of drugs, which includes determination of biological activity, biological effects, breakdown and synthesis, and delivery.
thermohaline convection	A type of hydrodynamic instability.
sessile	attached directly by the base (rather than being raised on a stalk)
rpif	Regional Planetary Imaging Data Facilities.
virtual pairs	Particles and antiparticles that exist for an extremely short time, often as the intermediate stage of a nuclear transition
crêpe ring	(a) Rather transparent inner ring (Ring C) of the saturn ring system
kelvin	The Kelvin (K) is the unit of the absolute temperature scale, in which the temperature of the triple point of water (the temperature at which water can exist simultaneously in solid, liquid and gaseous form) assumes the value of 273.16 K
mantle	The part of the Earth (or other rocky body) lying between the outer crust and the central core.
supervision	Responsibility for and control of quality, radiation safety, and technical aspects of all x-ray examinations and procedures.
electrodynamics	Study of the behavior of electromagnetic force in motion.
false vacuum	(a) A region of space that appears to be empty (a vacuum), but actually contains stored energy
terminal reaction	A reaction that ends a cycle or chain of other chemical reactions.
complex number	A type of number that is the sum of two parts, the first of which produces a positive number when multiplied by itself (like ordinary numbers), and the second of which produces a negative number when multiplied by itself (unlike ordinary numbers)
consistent	The property possessed by a scientific theory when it contains and extends an earlier well-supported theory; for example, general relativity is consistent with Newtonian gravity
1 orionis	see Trapezium
fermi-dirac-sommerfeld law	A law which gives the algebraic number of a quantized system of particles which have velocities within a small range
critical density	The current expansion of the Universe will be stopped in the future if the density of all the existing matter amounts to a particular value
nicol prism	A device made from a split crystal of Iceland spar with which plane-polarized light can be detected.
radio interferometer	Type of radio telescope that relies on the use of two or more aerials at a distance from each other to provide a combination of signals from one source which can be analyzed by computer
bolometer	A device for measuring the total amount of radiant energy received from a celestial object.
leap second	A second (see Second, Système International) added between 60s and 0s at announced times to keep UTC within 0s.90 of UT1
isothermal change	A process that takes place at constant temperature
semipermeable membrane	A membrane that allows some but not all of the components in a mixture to pass through it
human immunodeficiency virus	The virus that causes AIDS (acquired immune deficiency syndrome).
traps	Irregularities in the silicon crystal lattice which can absorb free charges created in the semiconductor by, for instance, the absorption of light
weber	The derived SI unit of magnetic flux
lox	Liquid oxygen.
ubv photometric system	(a) Measurement of the astronomical color index of a star, utilizing the ultraviolet, blue and yellow visual images over two pre-set wavelengths obtained by photoelectric filtering
short wave fade	An abrupt decrease of HF radio signal strength, lasting form minutes to hours, caused by increased day-side ionization from solar flares, usually M or X x-ray class.
ion	An electrically charged atom
mdscc	DSN's Madrid Deep Space Communications Complex in Spain.
accretion	(a) Collection of material together, generally to form a single body
regolith	The layer of fragmentary debris produced by meteoritic impact on the surface of the Moon or a planet.
stomatitus	Inflammation of the mouth.
deduction	Process of reasoning in which a conclusion is derived from a given premise or premises, without a need for additional information
phenolphthalein	An organic compound used as an acid-base indicator
arrow of time	The direction, apparently inviolable, of the "flow" of time that distinguishes the past from the future.The direction, apparently inviolable, of the "flow" of time that distinguishes the past from the future
winding number	The number of times a string is wound around a circular spatial dimension
string	(a) Fundamental one-dimensional object that is the essential ingredient in string theory
antibiotic	A drug that kills or reduces the growth of bacterial infection.
instrument	a device that requires skill for proper use
bremsstrahlung	The German word `Bremsstrahlung' means `braking radiation'
enthalphy	The heat content of a body
hyperbolic	Having the shape of a hyperbola, a particular form of curve whose two 'arms' diverge and never rejoin.
hdm	Hardness Design Margin
metamorphic rocks	rocks formed by the action of great heat and/or pressure
u line	A sodium line at 3302 Å
arc second	One-sixtieth of a arc minute on the sky
transit circle	Large instrument for the accurate observation and measurement of a transit
base si unit	a unit assumed to be mutually independent from which all other units are derived
spectrum	Electromagnetic radiation whose beam is dispersed like a natural rainbow so that components with different wavelengths are separated in space in order of increasing or decreasing wavelength
rare earth	An oxide of a rare earth element.
alfvén number	A dimensionless number characterizing steady fluid flow past an obstacle in a uniform magnetic field parallel to the direction of flow
measurements	Measurements made in a place to sample the local environment.
adiabatic demagnetization	A method of producing temperatures close to absolute zero
background noise	All the interference effects in a system which is producing, measuring, or recording a signal
gyroscope	A disc with a heavy rim mounted in such a way that its axis of rotation can adopt any position
absorption lines	Dark lines in a spectrum, produced when light or other electromagnetic radiation coming from a distant source passes through a gas cloud or similar object closer to the observer
plasma	The liquid part of the blood, lymph, and intracellular fluid in which cells are suspended.
recombination era	The time when matter and radiation first separated
umbriel	A satellite of Uranus about 400 km in diameter (period 4.1 days)
greenwich sidereal day number	The integral part of the Greenwich sidereal date
big bang theory	The theory that the Universe ‘started’ with an event that created time and space, about 13 billion years ago.
objective with correction ring	Why cover glass correction for an oil objective? Oil objectives should function equally well, regardless of whether they are used with or without a cover glass because the cover glasses and the oil should display an almost identical refractive index (homogeneous immersion)
emission coefficient	Radiant flux emitted per unit volume per unit solid angle
tracker	The part of a high-energy gamma-ray telescope that is used to determine the trajectory of the incoming gamma-ray
vv cephei star	Eclipsing binaries with M supergiant primaries and blue (usually B) supergiant or giant secondaries
femto	A prefix meaning 10-15
telemetry	Data and commands sent from the spacecraft to ground stations.
excision	Removal by surgery.
uncertainty principle	(a) The principle that the fundamental uncertainty in a variable times that in its canonical conjugate is of the order of Planck's constant: xp = h
baffle	A device used to prevent stray light.
geometry	The mathematics of lines drawn through space
mabthera	UK trade name for rituxan.
am	Attometer (10-18 m).
permanent effects	Changes in material properties that persist for a long time compared with the normal response time of the system of which the material is a part.
stromatolite	laminated sedimentary fossil formed from layers of blue-green algae
ionization potential	The minimum energy required to remove an electron from an atom
cte	Charge Transfer Efficiency A term used to characterize the amount of charge successfully moved from pixel to pixel in a CCD
ephemeris	(a) A list or tabulation of astronomical phenomena that change with time
maunder minimum	virtual disappearance of sunspots in the period 1645 to 1715
pressure	The force exerted over a surface divided by its area.
lookback time	How long ago a distant object emitted the light we now see
dl	Design Limits
carinae	see Canopus
formamide	HCONH2 -- A molecule discovered in interstellar space in 1971 at 6.5 cm
cesium clock	An apparatus used to produce the steady frequency used in defining the second
n	Newton, the SI unit of force equal to that required to accelerate a 1-kg mass 1 m per second per second (1m/sec2)
nucleoside	compound consisting of a sugar and a purine of pyrimidine base
second	the SI base unit of time
inversion layer	a very thin layer of electrons trapped on an interface between a semiconductor and an insulator, or between two different semiconductors
signature	A new particle will have some characteristic behavior in a detector that allows it to be recognized
fresnel lens	A type of lens with one surface cut in steps so that transmitted light is refracted just as if by a much thicker (and heavier and more expensive) conventional lens
anemia	A condition caused by a reduction in the amount of red blood cells or hemoglobin
ims	Integrated Master Schedule
cellulose	A polysaccharide made of linked glucose molecules that strengthens the cell walls of most plants
x radiation	electromagnetic radiation in the range of approximately 0.05-100Å.
aiming cylinder	A round/circular metal tube/shield attached to the X-ray tube housing or placed in front of the x-ray tube to limit the size of the x-ray beam to a predetermined size and shape.
feautrier's method	A difference-equation method of solving transfer equations
diuretics	drugs that help the body get rid of excess water and salt.
anisotropic models	see Mixmaster Model
even-even nuclei	see 4N Nuclei
film speed	A relative exposure number needed to produce a density of 1/0 above gross fog-used for screen type, dental and medical x-ray films.
doppler shift	The change in frequency of a wave (light, sound, etc.) due to the relative motion of source and receiver.
inclination	(a) In astronomy, the angle between one plane and another
vogt-russell theorem	If the pressure, the opacity, and the energy generation rate are functions of the local values of density, temperature and the chemical composition only, then the structure of a star is uniquely determined by the mass and the chemical composition
eccentric anomaly	In undisturbed elliptic motion, the angle measured at the center of the ellipse from pericenter to the point on the circumscribing auxiliary circle from which a perpendicular to the major axis would intersect the orbiting body
tunnel diode	A highly doped p-n junction diode that has a large reverse current, and, in the forward direction, a negative slope resistance over part of the voltage-current characteristic
graphite	An amorphous form of carbon, made of carbon atoms bound hexagonally in sheets (like chickenwire).
lane-emden equation	A second-order nonlinear differential equation describing the structure of polytropes
smd	Science Mission Directorate, NASA (previously Office Of Space Science, OSS).
mie diffraction	The diffraction of light by small spherical particles.
frequency	The rate at which a wave oscillates: the number of full cycles performed by the wave in a second
closed string	A type of string that is in the shape of a loop
aplastic anemia	A deficiency of certain types of blood cells caused by poor bone marrow function.
tcm	Trajectory Correction Maneuver, spacecraft propulsive maneuver.
radiation	The emission of energy by waves (including light) or particles.
immune system	The system within the body that recognizes and fights foreign cells and disease.
el	Elevation.
equatorial velocity	The velocity at the surface of a rotating body, on its equator
impact crater	See Crater
vis viva equation	An equation governing the conservation of angular momentum
aaas	American Association for the Advancement of Science.
vertex	see Radiant [H76]
conservation law	Law that identifies a quantity, such as energy, that remains unchanged throughout a transformation
veneziano theory	A formula that accounted for the experimental results of the dual resonance model
knudsen number	The ratio of the mean free path length of the molecules in a fluid to a characteristic length of the structure in the fluid stream
virtual particle	(a) A quantum particle that exists only temporarily, for example while being exchanged between other particles
neurotransmitter	Neurotransmitters are molecules that are used to carry signals from one neuron to another
personal dosimeters	Devices designed to be worn or carried by an individual for the purpose of determining the dose equivalent received for example: film badge, pocket chamber, pocket dosimeter, ring badges, thermoluminescent (TLD) badges, etc.
figure of merit	The extent to which an optical system falls short of perfection
secondary barrier	Barrier sufficient to attenuate stray radiation to the required degree.
resolution	The size of the smallest detail visible in an image
ultraviolet	The region of the electromagnetic spectrum with wavelengths in the range of 10-9 meters to 4 x 10-7 meters
los	Loss Of Signal, used in DSN operations.
laser	Light Amplification by Stimulated Emission of Radiation
mli	Multi-layer insulation (spacecraft blanketing)
geoid	(a) The equipotential surface ("mean sea level") of Earth's gravitational field
radial velocity	Velocity along the line of sight toward (-) or away from (+) the observer.
riemannian geometry	A large class of non-Euclidean geometries
femtometer	10-15 meter.
toxicology	The study of poisons, including identification, isolation, biological effects, mechanism of action, and development of antidotes.
light clock	A hypothetical clock that measures elapsed time by counting the number of round-trip journeys completed by a single photon between two mirrors
autotroph	organism whose metabolism requires only external sources of carbon dioxide and nitrogen
gauss	(a) The cgs unit of magnetic flux density
pe	Post Encounter phase in flyby mission operations.
inertial mass	The mass of an object as measured by the property of inertia
refraction	The deflection or bending of electromagnetic waves when they pass from one kind of transparent medium into another.
geodesy	Measurement and study of the Earth's size and shape.
tumor marker	Proteins and other substances found in the blood that signify the presence of cancer somewhere in the body.
bone marrow transplantation	Treatment in which healthy bone marrow replaces bone marrow that has been affected by a disease or by treatment for a disease
tdrss	Transmission Data and Relay Satellite System
vertical	Apparent direction of gravity at the point of observation (normal to the plane of a free level surface.) [S92]
red supergiant	A supergiant with spectral type M
viscous	Characterized by resistance to flow due to internal friction within a fluid.
light	Electromagnetic radiation that is visible to the eye.
iers	International Earth Rotation and Reference Systems Service
cluster mission	ESA cornerstone mission to explore the interaction between the Sun and the Earth's magnetosphere
panspermia	diffusion of spores or molecular precursors of life through space
t-cell lymphoma / leukemia	A condition caused by infection with the retro-virus human T-cell lymphotropic virus type I. Classified as an aggressive non-hodgkin's lymphoma
element	Set of stable atoms from which all known molecules are made out
tunnel effect	The passage of a particle through a potential barrier, even though it has not enough energy to pass the barrier on classical grounds
density	Film blackening (the amount of light transmitted through the film.)
scientific notation	A compact format for writing very large or very small numbers, most often used in scientific fields
aerosol	A gaseous suspension of ultramicroscopic particles of a liquid or a solid.
mother liquor	The solution in recrystallization.
dose equivalent	Means the product of the absorbed dose in tissue, quality factor, and all other necessary modifying factors at the location of interest
hemt	High-electron-mobility transistor, a low-noise amplifier used in DSN.
platform	Main supporting structure of a spacecraft accommodating its main subsystems such as propellant, flight electronics and communications.
flattening	A parameter that specifies the degree by which a planet's figure differs from that of a sphere; the ratio f = (a - b) / a, where a is the equatorial radius and b is the polar radius
aurora	the light produced by excited atoms and ions in the upper atmosphere of a planet
stem cell collection	See Apheresis.
metallic compounds	Compounds that contain at least one metallic element.
aas	American Astronomical Society.
jiic	Junction Isolated Integrated Circuit
component	1
bethe-weizsäcker cycle	(a) See proton-proton cycle
adsorption chromatography	A technique for separating or analyzing mixtures that contain at least one component that is preferentially adsorbed by the stationary phase as it moves over it.
trigonal planar	A molecular shape that results when there are three bonds and no lone pairs around the central atom in the molecule
diffuse x-ray background	An X-ray emission not associated with known individual sources
ionization potential	(a) The energy required to remove an electron from an atom or molecule to form a positive ion
sgemp	System Generated Electromagnetic Pulse
themis	A satellite of Saturn discovered by Pickering in 1900, but since lost
charged particles	Particles with positive or negative charge, for example electrons, protons or ions.
fog or fogging	A cloudy appearance of the finished radiograph caused by several factors such as old or contaminated processing solutions, exposure to chemical fumes, faulty darkroom safelight, or scatter radiation.
halo orbit	A spacecraft's pattern of controlled drift about an unstable Lagrange point (L1 or L2 for example) while in orbit about the primary body (e.g
fringes	(a) The light and dark bands obtained by interference or diffraction of light
argument of periapsis	The argument (angular distance) of periapsis from the ascending node.
solvent	The most abundant component in a solution.
bepposax satellite	An Italian-Dutch X-ray astronomy satellite launched in 1996.
imaging	Making an image.
tld	Thermoluminescent Dosimeter
wave function	(a) The mathematical object in quantum theory which determines probabilities of different results of experiments
atomic weight	The mean atomic mass of a particular element in atomic mass units