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- Cae, Cael
- International Astronomical Union abbreviations for Caelum. See constellation.
- Caelum (abbr Cae, Cael)
- See constellation.
- To lock a gyro in a fixed
position in its case.
- The process of orienting and mechanically locking the spin axis of a gyro to an
internal reference position.
- caisson disease
- Those conditions including collapse, neurological changes, and pain,
associated with relatively rapid reduction of ambient pressure from levels
appreciably higher than 1 atmosphere to 1 atmosphere; and due to the release
of inert gases in the body. Also called compressed air illness, bends.
- calculating punch
- A punched-card machine in which information is read from cards, and the
results of sequential operations are punched on cards as they pass through the
- An orderly arrangement of days, weeks, months, etc. to suit a particular
need such as civil life. See Julian Day.
- calendar day
- The period from midnight to midnight. The calendar day is 24 hours of mean solar
time in length and coincides with the civil day
unless a time change occurs during the day.
- calendar year
- The year of the Gregorian
calendar, common years having 365 days and leap years 366 days.
- Each year exactly divisible by 4 is a leap year, except century years
(1800, 1900, etc.), which must be exactly divisible by 400 (2000, 2400, etc.)
to be leap years. The calendar year is based on the tropical
year. Also called civil year.
- calibration marker
- In radar, a calibration mark on the display to
delineate bearing, distance, height, or time.
- Callipic cycle
- Four Metonic
cycles or 76 years.
- A satellite of Jupiter orbiting at a mean distance of 1,884,000
kilometers. Also called Jupiter IV.
- call number
- In computer operations, a set of characters identifying a subroutine
and containing (a) information concerning parameters to be inserted in the
subroutine, (b) information to be used in generating the subroutine, or (c)
information related to the operands.
- calorie (abbr cal)
- A unit of heat originally defined as the amount of heat required to raise
the temperature of 1 gram of water through 1° C (the gram-calorie or small
- Several calories are now in use: International Steam Table calorie =
4.1868 joules, mean calorie = 4.19002 joules, thermochemical calorie = 4.184
joules, 15° C calorie = 4.18580 joules, 20° C = 4.1890 joules. The kilogram
calorie or kilocalorie is 1000 times as large as a calorie.
- An instrument designed to measure heat evolved or
- Calorimeters are used in some pyrheliometers.
- Cam, Caml
- International Astronomical Union abbreviations for Camelopardus.
- Camelopardus (abbr Cam, Caml)
- See constellation.
- International Astronomical Union abbreviation for Camelopardus. See
- Pertaining to an aerodynamic
vehicle in which horizontal surfaces used for trim and control are forward
of the main lifting surface; the horizontal trim and control surfaces in such
- International Astronomical Union abbreviation for Cancer. See constellation.
- Cancer (abbr Cnc, Canc)
- See constellation.
- candela (symbol cd)
- The luminous intensity, in a given direction, of a source that emits
monochromatic radiation of frequency 540 * 1012 hertz and that has
a radiant intensity in that direction of (1/683) watt per steradian (16th CGPM
(1979), Resolution 3).
The previous is an excerpt from WWW version of the National Institute of
Standards and Technology: Physics Laboratory's International System of Units
Also called candle.
- candle = candela.
- Canes Venatici (abbr Cvn, C Ven)
- See constellation.
- Canis Major (abbr CMa, C Maj)
- See constellation.
- Canis Minor (abbr CMi, C Min)
- See constellation.
- canonical time unit
- For geocentric orbits, the time required by a hypothetical satellite to
move one radian in a circular orbit of the
earth's equatorial radius; 13.447052 minutes.
- Cap, Capr
- International Astronomical Union abbreviations for Capricornus. See
- A power or capacity to do something. Compare characteristic.
- Capabilities belong to people, organized forces, or things.
- In computer operations, (a) the largest quantity which can be stored,
processed, or transferred; (b) the largest number of digits or
characters which may regularly be processed; (c) the upper and lower limits of
the quantities which may be processed.
- International Astronomical Union abbreviation for Capricornus. See
- Capricornus (abbr Cap, Capr)
- See constellation.
- 1. A boxlike component or unit, often sealed. See aneroid.
- 2. A small, sealed, pressurized cabin with an internal environment
which will support life in a man or animal during extremely high altitude
flight, space flight, or emergency escape. See ejection
- The term spacecraft is preferred to capsule for any man-carrying
- 3. A container carried on a rocket or spacecraft, as an instrument
capsule holding instruments intended to be recovered after a flight.
- captive test
- A holddown
test of a propulsion subsystem, rocket engine or motor. Distinguished from
a flight test.
- 1. Of a central force filed, as of a planet; to overcome by gravitational
force the velocity of a passing body and bring the body under the control of
force field, in some cases absorbing its mass.
- 2. Acquisition or absorption of an additional particle by an atomic nucleus.
- capture effect
- An effect in frequency
modulation (FM) reception where the stronger signal of two stations on the
same frequency completely suppresses the weaker signal.
- The use of a torquer to
restrain the spin axis of a gyro to a
specified position relative to the spin reference axis.
- Car, Cari
- International Astronomical Union abbreviations for Carina. See constellation.
- A compound of carbon with one or more metallic elements.
- carbon cycle
- A sequence of atomic nuclear
reactions and spontaneous radioactive
decay which serves to convert matter into energy in the form of radiation
and high-speed particles, and which is regarded as one of the principal
sources of the energy of the sun and other similar stars.
- This cycle, first suggested by Bethe in 1938, gets its name from the
fact that carbon plays the role of a kind of catalyst in that it is both used
by and produced by the reaction, but is not consumed itself. Four protons are,
in net, converted into an alpha particle and two positrons (with accompanying
neutrinos); and three gamma-ray emissions are emitted directly in addition to
the two gamma emissions that ensue from annihilation of the positrons by
ambient electrons. This cycle sets in at stellar interior temperatures of the
order of 5 million degrees Kelvin.
An even simpler reaction, the proton-proton
reaction, is also believed to occur within the sun and may be of equal or
- The origination or production of cancer.
- 1. A punched card, used in computer
operations for the storage of information in the form of holes punched through
the card material.
- Standard punched cards are 7.375 x 3.250 x 0.007 inches, containing
either 80 columns in each of which any of 12 positions may be punched or 90
columns in each of which any combination of 6 places may be punched.
- 2. Any card adapted for the storage of information.
- 3. A printed-circuit board,
usually before other parts are mounted therein. See module, package.
- Pertaining to the heart and the blood vessels.
- card punch
- A mechanism which punches holes in cards used in computer
- An automatic card punch punches cards according to a stored
- card reader
- A mechanism that reproduces the information on punched cards in another
form, usually electrical signals.
- International Astronomical Union abbreviation for Carina. See constellation.
- Carnot cycle
- An idealized reversible thermodynamic
cycle. The Carnot cycle consists of four stages: (a) an isothermal expansion
of the gas at temperature T1; (b) an adiabatic expansion to
temperature T2; (c) an isothermal
compression at temperature T2; (d) an adiabatic
compression to the original state of the gas to complete the cycle. See Carnot
- In a Carnot cycle, the net work done is the difference between the heat
inputQ1at higher temperatureT1and the heat
extractedQ2at the lower temperatureT2.
- Carnot efficiency = thermodynamic
- Carnot engine
- An idealized reversible heat engine
working in a Carnot
cycle. It is the most efficient engine that can operate between two
specified temperatures; its efficiency is equivalent to the thermodynamic
efficiency. The Carnot engine is capable of being run either as a
conventional engine or as a refrigerator.
- 1. In a semiconductor,
a mobile conduction electron or hole.
- 2. In modulation of a signal, a wave suitable for
being modulated as a sine wave, a recurring series of pulses, or a direct
- carrier frequency
- The frequency of
- carrier operated device,
anti-noise = codan
- carrier rocket
- A rocket
vehicle used to carry something, as in the carrier rocket of the first
artificial earth satellite.
- carrier wave (abbr cw)
- A wave
generated at a point in the transmitting system and modulated by the signal.
- carry time
- In computer operations, the time required for a binary
chain to complete its response to an input pulse.
- Cartesian coordinates
- A coordinate
system in which the locations of points in space are expressed by
reference to three planes, called coordinate planes, no two of which are
parallel. Compare curvilinear
- The three planes intersect in three straight lines, called coordinate
axes. The coordinate planes and coordinate axes intersect in a common point,
called the origin. From any point P in space three straight lines may be
drawn, each of which is parallel to one of the three coordinate planes. If A,
B, C denote these points of intersection, the Cartesian coordinates of P are
the distances PA, PB, and PC. If the coordinate axes are mutually
perpendicular, the coordinate system is rectangular; otherwise, oblique.
- Cas, Cass
- International Astronomical Union abbreviations for Cassiopeia. See
- Of a series of elements or devices, arranged so that the output of one
feeds directly into the input of another,
as a series of dynodes or a
series of airfoils.
- The cascaded series usually serves to amplify the effect.
- cascade shower
- A group occurrence of cosmic
rays. Also called air shower.
- International Astronomical Union abbreviation for Cassiopeia. See
- Cassegrain = Cassegrain
- Cassegrainian telescope = Cassegrain
- Cassegrain telescope
- A reflecting telescope in which a small hyperboloidal mirror reflects the
convergent beam from the paraboloidal primary mirror through a hole in the
primary mirror to an eyepiece in back of the primary mirror. Also called
Cassegrainian telescope, Cassegrain. See Newtonian
- Cassiopeia (abbr Cas, Cass)
- See constellation.
- catalogue = star
- catalogue number
- The designation of a star by the name of a particular star
catalogue and the number of the star in that catalogue.
- A power-actuated machine or device for hurling forth something, an
airplane or missile, at a high initial speed; also, a device, usually
explosive, for ejecting a person from an aircraft. Compare launcher,
senses 1 and 2.
- A hollow tube of metal, glass, hard or soft rubber, rubberized silk, etc.,
for introduction into a body cavity through a narrow canal, for the purpose of
discharging the fluid contents of a cavity or for establishing that the canal
- In an electron tube, an electrode
through which a primary stream of electrons enters the interelectrode space.
cathode, hot cathode
(thermionic cathode), photocathode.
- cathode-ray indicator = cathode-ray
- cathode-ray oscillograph = cathode-ray
- cathode-ray oscilloscope
- An instrument which displays visually on the face of a cathode-ray
tube instantaneous voltages of electrical signals. Either the intensity or
the displacement of the trace may be controlled by the signal voltage. More
commonly called oscilloscope. Also called cathode-ray
oscillograph. See radarscope.
- cathode-ray tube (abbr CRT)
- A vacuum tube consisting essentially of an electron
gun producing a concentrated electron beam (or cathode ray) which impinges
on a phosphorescent coating on the back of a viewing face (or screen). The excitation
of the phosphor
produces light, the intensity of which is controlled by regulating the flow of
electrons. Deflection of the beam is achieved either electromagnetically by
currents in coils around the tube, or electrostatically by voltages on
internal deflection plates.
- cathode rays
that are driven from the negative electrode (the cathode) of a
- cathode-ray screen
- See cathode-ray
- catoptric light
- A light concentrated into a parallel beam by means of a reflector.
- A light so concentrated by means of refracting lenses or prisms is a
- cat whisker
- A fine wire pickoff,
specifically a gyro
- Cauchy number
- A nondimensional number arising in the study of the elastic properties of
a fluid. It may be written U2p/E, where U is a
characteristic velocity; p (lower case Rho) is the density; and
E the modulus of elasticity of the fluid. It is the square of the Mach
- The formation of bubbles in a liquid, occurring whenever the static
pressure at any point in the fluid flow becomes less than the fluid vapor
- cavity heat receiver = hohlraum.
- cavity resonator
- See resonator.
- See frequency
- In radar, a rectangular display in
which targets appear as blips with
bearing indicated by the horizontal coordinate and angles of elevation by the
vertical coordinate. Also called C-scan and C-scope.
- 1. Of or pertaining to the heavens.
- 2. Short for celestial navigation.
- celestial body
- Any aggregation of matter in space constituting a unit for astronomical
study, as the sun, moon, a planet, comet, star, nebula, etc. Also called
- celestial coordinates
- Any set of coordinates
used to define a point on the celestial
- The horizon, celestial equator, ecliptic, and galactic systems of
celestial coordinates are based on the celestial horizon, celestial equator,
ecliptic, and galactic equator, respectively, as the primary
great circle. See coordinate,
VI, for a comparison of the systems.
- celestial equator
- The primary
great circle of the celestial
sphere in the equatorial
system, everywhere 90° from the celestial poles; the intersection of the
extended plane of the equator and the celestial sphere. Also called
- celestial equator system of coordinates = equatorial
- celestial guidance
- The process of directing movements of an aircraft or spacecraft,
especially in the selection of a flight
path, by reference to celestial bodies. Also called automatic celestial
navigation. See guidance, celestial
- celestial horizon
- That great
circle of the celestial
sphere formed by the intersection of the celestial
sphere and a plane through the center of the earth and perpendicular to
the zenith-nadir line. Also called rational horizon. See horizon, horizon
- celestial-inertial guidance
- The process of directing the movements of an aircraft or spacecraft,
especially in the selection of a flight path, by an inertial
guidance system which also receives inputs from observations of celestial
- celestial latitude
- Angular distance north or south of the ecliptic; the
arc of a circle
of latitude between the ecliptic and a point on the celestial
sphere, measured northward or southward from the ecliptic through 90°, and
labeled N or S to indicate the direction of measurement. See ecliptic
system of coordinates.
- celestial line of position
- A line of
position determined by observation of one (or more) celestial bodies.
- celestial longitude
- Angular distance east of the vernal
equinox, along the ecliptic; the
arc of the ecliptic or the angle at the ecliptic pole between the circle
of latitude of the vernal equinox and the circle of latitude of a point on
the celestial sphere, measured eastward from the circle of latitude of the
vernal equinox, through 360°. See ecliptic
system of coordinates.
- celestial mechanics
- The study of the theory of the motions of celestial
bodies under the influence of gravitational fields. See gravitation.
- celestial meridian
- A great
circle of the celestial
sphere, through the celestial poles and the zenith.
- The expression usually refers to the upper branch, that half of the
great circle from pole to pole which passes through the zenith; the other half
being the lower branch. The celestial meridian coincides with the hour circle
through the zenith and the vertical
circle through the elevated pole.
- celestial navigation
- The process of directing a craft from one point to another by reference to
bodies of known coordinates.
- Celestial navigation usually refers to the process as accomplished by a
human operator. The same process accomplished automatically by a machine is
usually termed celestial guidance or sometimes automatic celestial
- celestial observation
- In navigation, the measurement of the altitude of a
body, or the measurement of azimuth, or
measurement of both altitude and azimuth. Also called sight.
- The expression may also be applied to the data obtained by such
- celestial pole
- Either of the two points of intersection of the celestial
sphere and the extended axis of the earth, labeled N or S to
indicate whether the north celestial pole or the south celestial
- celestial sphere
- An imaginary sphere of infinite radius concentric with the earth, on which
bodies except the earth are assumed to be projected.
- celestial triangle
- A spherical triangle on the celestial
sphere, especially the navigational
- In computers, an elementary unit of storage, as
binary cell, decimal cell.
- Celsius temperature scale (abbr C)
- Same as centigrade
- The Ninth General Conference on Weights and Measures (1948) replaced
the designation degree centigrade by degree Celsius.
- Cen, Cent
- International Astronomical Union abbreviation for Centaurus. See constellation.
- In acoustics, the interval between two sounds whose basic frequency
ratio is the twelve-hundredth root of 2.
- Centaurus (abbr Cen, Cent)
- See constellation.
- center frequency
- The assigned carrier
frequency of a frequency
modulation (FM) station; the unmodulated frequency of an FM system.
- center of mass
- That point in a given body, or in a system of two or more bodies that act
together in respect to another body, which represents the mean position of the
matter in the body of bodies. See barycenter.
- center of thrust = thrust
- centi (abbr C)
- A prefix meaning one-hundredth.
- centigrade temperature scale (abbr C)
- A temperature scale with the ice point at 0° and the boiling point of
water at 100°. Now called Celsius temperature scale.
- Conversion to the Fahrenheit temperature scale is according to the
° C = 5/9 (°F - 32)
- centimeter (abbr cm)
- One-hundredth of a meter; approximately 0.3937 U.S. inch, exactly 1/2.54
- centimeter-gram-second system (abbr cgs)
- A system of units based on the centimeter as the unit of length, the gram
as the unit of mass, and the second as the unit of time.
- centimetric waves.
- See frequency
- centipoise (abbr cp)
- A unit of viscosity.
- central control
- 1. Control exercised over an extensive and complicated system from a
- 2. Usually capitalized. The place, facility, or activity from which this
control is exercised; specifically, at Cape Canaveral or at Vandenberg AFB,
the place, facility, or activity at which the whole action incident to a test
launch and flight is coordinated and controlled, from the make-ready at the
launch site and on the range, to the end of the rocket flight downrange.
- For a few seconds during the actual launch, control of a missile is
exercised from the blockhouse,
but it almost immediately reverts to Central Control for guidance and
tracking, with two men in essential control. One of these is the supervisor of
range operations, the other is the range safety officer.
- central force
- A force
which for purposes of computation can be considered to be concentrated at one
central point with its intensity at any other point being a function of the
distance from the central point.
is considered as a central force in celestial mechanics.
- central force field
- The spatial distribution of the influence of a central
- centrifugal acceleration = centrifugal
- centrifugal compressor
- A compressor
having one or more vaned rotary impellers
which accelerate the incoming fluid radially outward into a diffuser,
compressing by centrifugal force. Sometimes called a centrifugal-flow
compressor . Compare axial-flow
- centrifugal-flow compressor = centrifugal
- centrifugal force
- The apparent
force in a rotating system, deflecting masses radially outward from the
axis of rotation, with magnitude per unit mass
2R, where is the angular
speed of rotation; and R is the radius of curvature of the path. This
magnitude may also be written as V2/R, in terms of the
linear speed V. This force (per unit mass) is equal and opposite to the
acceleration. Also called centrifugal acceleration.
- The centrifugal force on the earth and atmosphere due to rotation about
the earth's axis is incorporated with the field of gravitation to form the
field of gravity.
- Specifically, a large motor-driven apparatus with a long arm at the end of
which human and animal subjects or equipment can be revolved and rotated at
various speeds to simulate (very closely) the (prolonged) accelerations
encountered in high-performance aircraft, rockets, and spacecraft. Sometimes
called astronautic centrifuge.
- centripetal acceleration
- The acceleration
on a particle moving in a curved path, directed toward the instantaneous
center of curvature of the path, with magnitude v2/R, where
v is the speed of the particle and R the radius of curvature of
the path. This acceleration is equal and opposite to the centrifugal
force per unit mass.
- CEP (abbr) = circle
of equal probability.
- Cep, Ceph
- International Astronomical Union abbreviations for Cepheus. See constellation.
- Cepheus (abbr, Cep, Ceph)
- See constellation.
- caramel = cermet.
- An inorganic compound or mixture requiring heat treatment to fuse it into
a homogeneous mass usually possessing high temperature strength but low
ductility. Types and uses range from china for dishes to refractory
liner for nozzles.
- Cerenkov radiation
- The radiation
from a charged particle whose
velocity is greater than the phase
velocity that an electromagnetic wave would have if it were propagating in
the medium. The particle will continue to lose energy by radiation until its
velocity is less than this phase velocity.
- This phenomenon is analogous to the generation of a shock wave when an
object is traveling faster than the sound velocity of the medium. A bow wave
is set up which radiates energy into the medium and slows down the object.
The angle that the cone of luminescence
makes with the direction of motion of the particle can be used to measure the
velocity of the particle.
- cermet [ceramic + metal]
- A body consisting of ceramic particles bonded with a metal; used in
aircraft, rockets, and spacecraft for high strength, high temperature
applications. Also called ceramal [ceramic + alloy].
- Cet, Ceti
- International Astronomical Union abbreviations for Cetus . See constellation.
- cetane number
- A number indicating the relative ignitability of a fuel oil for
- International Astronomical Union abbreviations for Cetus . See constellation.
- Cetus (abbr Cet, Ceti)
- See constellation.
- C-figure = C-index
- CGS system
- A system of units based on the centimeter, the gram, and the second.
- Cha, Cham
- International Astronomical Union abbreviations for Chamaeleon. See
- The piece removed when punching a hole, as in a card. See chadless.
- A type of punching in which the chad is left
attached by about 25 percent of the circumference of the hole, at the leading
- Chadless punching is used where it is undesirable to mutilate
information written or printed on the punched medium.
- chaff = window.
- chain radar beacon
- A radar
beacon with a very fast recovery time.
- This recovery time provides the possibility of simultaneously
interrogating and tracking the beacon by as many radars as required so long as
they are phased, synchronized, or the sum total pulse recurrence frequency
does not exceed the maximum pulse recurrence frequency characteristics of the
- chain reaction
- A reaction in which one of the agents necessary to the reaction is itself
produced by the reaction, thus causing like reactions.
- In the neutron-fission chain reaction, a neutron striking a fissionable
atom causes a fission releasing neutrons which cause other fissions.
- challenger = interrogator-responsor.
- International Astronomical Union abbreviation for Chamaeleon. See
- Chamaeleon (abbr Cha, Cham)
- See constellation.
- chamber = combustion
- chamber pressure (symbol Pc)
- The pressure of gases within the combustion
chamber of a rocket engine.
- chamber volume (symbol Vc)
- The volume of the rocket combustion chamber including the convergent
portion of the nozzle up to the throat.
- change of the moon = new moon.
- 1. Short for frequency channel.
- 2. In computer operations: (a) That portion of a storage medium
which is accessible to a given reading station. See track. (b) A path
of flow, usually including one or more operations.
- Chapman region
- A hypothetical region in the upper
atmosphere in which the distribution of electron density with height can
be described by a theoretical equation derived by Sydney Chapman.
- Some of the basic assumptions used to develop the equation were that
the ionizing radiation from the sun is essentially monochromatic, that the
ionized constituent is distributed exponentially (with a constant scale
height), and that there is an equilibrium condition between the creation
of free electrons and their loss by recombination.
- Chappius bands
- See absorption
- One of a set of elementary marks or events which may be combined to
- For example, a decimal digit (0 to 9), a letter (A to Z), or a symbol
(comma, plus, minus, etc.).
- Specifically, a distinguishing quality, property, feature, or capability
of a machine or piece of equipment, or of a component part.
- The characteristics of an aircraft are (1) qualities such as stability,
maneuverability, and strength; (2) features such as number, kind, or power of
engines, and size, shape, or number of wings; and (3) capabilities such as
range, speed, and payload.
- characteristic chamber length (symbol L*)
- The length of a straight cylindrical tube having the same volume as the
chamber of a rocket
engine would have if it had no converging section.
- characteristic equation
- 1. An equation defining the characteristics of a set of partial
- 2. A linear algebraic equation determining the eigenvalues
or free waves of a boundary-value problem. See characteristic
- characteristic exhaust velocity (symbol c*)
- Of a rocket
engine, a descriptive parameter,
c* = Ve/CF where
Ve is effective exhaust velocity and CF is
thrust coefficient. Also called characteristic velocity.
- characteristic Larmor radius
- The size of the Larmor
orbit of a charged particle whose rotational velocity is equal to the Alfvén
- characteristic length (symbol l, )
- A convenient reference length (usually constant) of a given configuration,
such as overall length of an aircraft, the maximum diameter or radius of a
body of revolution, a chord or span of a lifting surface, etc.
- characteristic mode = normal
mode of vibration.
- Lines or surfaces associated with a partial differential equation, or with
a set of such equations, which are at all points tangent to characteristics
directions, determined by certain specified linear combinations of the
- The use of these lines or surfaces may facilitate the solution of the
equations and is known as the method of characteristics. The method has been
particularly successful, for example, in the problem of finite-amplitude
expansion and shock waves.
- characteristic value
- See characteristic
- characteristic-value problem
- A problem in which an undetermined parameter is
involved in the coefficients of a differential equation, and in which the
solution of the differential equation, with associated boundary conditions,
exists only for certain discrete values of the parameter, called
eigenvalues, or characteristic values, sometimes principal
- An important example of a physical problem which leads to a
characteristic-value problem is the determination of the modes and frequencies
of a vibrating system. In this case the dependent variable of the differential
equation represents the displacements of the system and the parameter
represents the frequencies of vibration.
- characteristic velocity (symbol c*) = characteristic
- charge neutrality
- The approximate equality of positive and negative particles in
- This phenomenon, which is sometimes called electrical
neutrality, is a result of the extremely large electric space charge fields
that would arise if the densities were not equal. Although the positive and
negative charge densities are seldom exactly equal, their percentage
difference is so small as to be negligible. It is not difficult to maintain
this condition in an active plasma since ionization
always produces or destroys an ion pair together.
- charge spectrum
- The range and magnitude of electric charges with reference to cosmic rays
at a specific altitude.
- Charles-Gay-Lussac law
- An empirical generalization that in a gaseous system at constant pressure,
the temperature increase and the relative volume increase stand in
approximately the same proportion for so-called perfect gases. Mathematically,
t - t0 + (1 / c [ ( v - v0 ) /
v0] where t is temperature; v is volume;
and c is a coefficient of thermal expansion independent of the
particular gas. If the centrigrade temperature scale is used and v0
is the volume at 0° C, then the value of the constant c is approximately
1/273. Also called Charles law, Gay-Lussac law.
- Charles law = Charles-Gay-Lussac
- charring ablator
- An ablation
material characterized by the formation of a carbonaceous layer at the
heated surface which impedes heat flow into the material by it insulating and
- chase pilot
- A pilot who flies an escort airplane advising a pilot who is making a
check, training, or research flight in another craft.
- The vehicle that maneuvers in order to effect a rendezvous
with an orbiting object.
- check flight
- 1. A flight made to check or test the performance of an aircraft, rocket,
or spacecraft, or a piece of equipment or component, or to obtain measurements
or other data on performance; a test
- 2. A familiarization flight in an aircraft, or a flight in which a pilot
or other aircrew member or members are tested or examined for proficiency.
- Presence of a network of fine hairline cracks on the surface of a
structure usually induced by poor machining technique.
- 1. A sequence of actions taken to test or examine a thing as to its
readiness for incorporation into a new phase of use, or for the performance of
its intended function.
- 2. The sequence of steps taken to familiarize a person with the operation
of an airplane or other piece of equipment.
- In sense 1, a checkout is usually taken at a transition point between
one phase of action and another. To shorten the time of checkout, automation
is frequently employed.
- checkout GSE
support equipment used to make a checkout,
which see, sense 1.
- cheese antenna
- A cylindrical parabolic
reflector enclosed by two plates perpendicular to the cylinder, so spaced
as to permit the propagation of more than one mode in the desired direction of
- chemical energy
produced or absorbed in the process of a chemical reaction. In such a
reaction, energy losses or gains usually involve only the outermost electrons of
the atoms or ions of the system undergoing change; here a chemical bond of
some type is established or broken without disrupting the original atomic or
ionic identities of the constituents.
- Chemical changes, according to the nature of the materials entering
into the change, may be induced by heat (thermochemical), light
(photochemical), and electric (electrochemical) energies.
- chemical fuel
- 1. A fuel
that depends upon an oxidizer for
combustion or for development of thrust, such as liquid or solid rocket fuel
or internal-combustion-engine fuel; distinguished from nuclear
- 2. A fuel that uses special chemicals, such as the fuel once projected for
the afterburner of the B-70.
- chemical pressurization
- The pressurization
of propellants tanks in a rocket by means
of high-pressure gases developed by the combustion of a fuel and oxidizer or
by the decomposition of a substance.
- Any luminescence
produced by chemical action. See airglow.
- The binding of a liquid or gas on the surface or in the interior of a
solid by chemical bonds or forces.
- The vaguely defined region of the upper atmosphere in which photochemical
reactions take place. It is generally considered to include the
stratosphere (or the top thereof) and the mesosphere, and sometimes the lower
part of the thermosphere. See atmospheric
- This entire region is the seat of a number of important photochemical
reactions involving atomic oxygen O, molecular oxygen O2, ozone
O3, hydroxyl OH, nitrogen N2, sodium Na, and other
constituents to a lesser degree.
- chest-to-back acceleration
- See physiological
- An all-encompassing term for the various techniques of pulse
expansion-pulse compression applied to pulse
radar; a technique to expand narrow pulses to wide pulses for
transmission, and compress wide received pulses to the original narrow pulse
width and wave shape, to gain improvement in signal-to-noise
ratio without degradation to range resolution and range discrimination.
- chi-square test
- A statistical significance test based on frequency of occurrence; it is
applicable both to qualitative attributes and quantitative variables. Among
its many uses, the most common are test of hypothesized probabilities or
probability distributions (goodness of fit), statistical dependence or
independence (association), and common population (homogeneity).
- The formula for chi square (x2) depends upon intended
use, but is often expressible as a sum of terms of the type (f -
h)2 / h where f is an observed frequency and h is
its hypothetical value.
- chlorate candle
- A mixture of solid chemical compounds which, when ignited, liberates free
- A genus of unicellular green algae, considered
to be adapted to converting carbon dioxide into oxygen in a closed ecological
system See closed
- choked flow
- Flow in a
duct or passage such that the flow upstream of a certain critical section
cannot be increased by a reduction of downstream pressure.
- Pain and irritation in the chest and throat as a result of reduced ambient
- choking Mach number
- The Mach
number at some reference point in a duct or passage (e.g., at the inlet)
at which the flow in the passage becomes choked. See choked
- A meteoritic stone characterized by small rounded grains or spherules.
- A device used to interrupt the path of radiation, as a beam of light, from
a single source or to alternate it between two sources.
- 1. A straight line intersecting a circle or other curve, or a straight
line connecting the ends of an arc.
- 2. (symbol c). In aeronautics, a straight line intersecting or
touching an airfoil profile at two points; specifically, that part of such a
line between two points of intersection.
- This line is usually a datum line
joining the leading and trailing edges of an airfoil, joining the ends of the
mean line of an airfoil profile, from which the ordinates and angles of the
airfoil are measured. As such a datum line, it is sometimes called the
geometric chord, to distinguish it from a chord established on the
basis of any other considerations.
- 3. = chord
- In sense 3, points or stations along a chord are designated in
percentages or fractions of the chord or chord length from the leading edge,
as, a point at 25 percent, or one-quarter, chord.
- chord length
- The length of the chord of an airfoil section
between the extremities of the section.
- For many airfoils, the chord is established intersecting the airfoil
profile at its extremities, and the chord length is equal to the length of the
chord between the points of intersection; for airfoils where the chord is
established by a point or points of tangency or intersection not at the
extremities, however, the chord length is considered to extend beyond either
or both points, as necessary, to equal the maximum length of the profile. See
chord, senses 2 and 3.
- See isotherm,
- The separation of chemical substances by making use of differences in the
rates at which the substances travel through or along a stationary medium.
- A thin layer or relatively transparent gases above the photosphere of the
- See isotherm,
- chronometer noon
- See solar noon.
- chronometer time
- See time.
- chronometric data
- Data in which the desired quantity is the time of occurrence of an event
or the time interval between two events.
- A device which utilizes a measurement of the position of the superposed
loci of a pair of pulses on a
transmission line to determine the time between the events which initiate the
- chuffing = chugging.
- A form of combustion
instability in a rocket
engine, characterized by a pulsing operation at a fairly low frequency,
sometimes defined as occurring between particular frequency limits; the noise
made in this kind of combustion. Also called chuffing, bumping.
- A subjectively obtained daily index of geomagnetic activity. Each day's
record is evaluated on the basis of 0 for quiet, 1 for moderately disturbed,
and 2 for very disturbed. Also called C-figure, magnetic character
figure. See geomagnetism.
- A photographic tracking
instrument which records on each film frame the target and the azimuth and
elevation angles of the optical axis of the instrument. Also called
- Cir, Circ
- International Astronomical Union abbreviations for Circinus. See constellation.
- circadian rhythm
- A regular change in physiological function occurring in approximately
- Circinus (abbr Cir, Circ)
- See constellation.
- circle of declination = hour
- circle of equal altitude = parallel
- circle of equal declination = parallel
- circle of equal probability (abbr CEP)
- A measure of the accuracy with which a rocket or missile can be guided;
the radius of the circle at a specific distance in which 50 percent of the
reliable shots land. Also called circular error probable, circle of
- circle of latitude
- A great
circle of the celestial
sphere through the ecliptic
poles, and hence perpendicular to the plane of the ecliptic.
- circle of longitude
- A circle of the celestial
sphere, parallel to the ecliptic. Also
called parallel of latitude.
- circle of probable error = circle
of equal probability.
- circle of right ascension = hour
- A network
providing one or more closed paths.
- circuit element
- See element, sense
- circular area
- Of a circle, the square of the diameter.
- Circular area = 1.2733 * true area.
True area = 0.785398 * circular
- circular cylindrical coordinates = cylindrical
- circular dispersion (abbr CD)
- In rocketry, the diameter of a circle within which 75 percent of the
events under study occur. CD = 3.330 where = standard deviation.
- Circular dispersion is most often used as a measure of error of the
accuracy with which rockets reach their intended target.
- circular error probable = circle
of equal probability.
- circular frequency = angular
frequency (symbol ).
- circular inch
- The area of a circle 1 inch in diameter.
- circularly polarized sound wave
- A transverse
wave in an elastic medium in which the displacement vector at any point
rotates about the point with constant angular velocity and has a constant
- A circularly polarized wave is equivalent to two super-posed plane
polarized waves of sinusoidal form in which the displacements have the same
amplitude, lie in perpendicular planes, and are in quadrature.
- circularly polarized wave
- An electromagnetic
wave for which the electric or the magnetic field vector, or both, at a
point describe a circle.
- This term is usually applied to transverse
- circular mil
- The area of a circle with a diameter of 0.001 inch; a unit used for the
measurement of small circular areas, such as the cross section of a wire.
- One circular mil = 7.85 x 10-7 square inch.
- circular polarization
- The polarization of a wave radiated by a
constant electric vector rotating in a plane so as to describe a circle. See
- circular scanning
- Scanning in
which the direction of maximum radiation generates a plane or a right circular
cone whose vertex angle is close to 180°.
- circular velocity
- At any specific distance from the primary, the orbital velocity required
to maintain a constant-radius orbit.
- circulating memory =delay-line
- circulating register = delay-line
- 1. The flow or motion of a fluid in or through a given area or volume.
- 2. A precise measure of the average flow of fluid along a given closed
curve. Mathematically, circulation is the line integral.
about the closed curve, where v
is the fluid velocity, and dr is a vector element of the curve.
- By Stokes theorem, the circulation about a plane curve is equal
to the total vorticity of the fluid enclosed by the curve.
The given curve
may be fixed in space or may be defined by moving fluid parcels.
- circulation integral
- The line integral of an arbitrary vector taken around a closed curve.
is the circulation integral
of the vector a around the closed curve; dr is an infinitesimal vector element
of the curve. If the vector is the velocity, this integral is called the
- Around the moon, generally applied to trajectories.
- [Latin cis, on this side]. Of or pertaining to phenomena, projects,
or activity in the space between the earth and moon, or between the earth and
the moon's orbit. Compare translunar,
- civil day
- See mean solar
- civil time
- See mean
- civil twilight
- See twilight,
- civil year = calendar
- clad = cladding.
- A coating placed on the surface of a material and usually bonded to the
material. Also called clad.
- Cladding is used extensively in nuclear reactor cores to prevent
corrosion of the fissionable material by the coolant.
- clamping circuit
- 1. A circuit which
maintains either extremity of a waveform at a
- 2. A network for
adjusting the absolute voltage level of a waveform.
- Clapeyron-Clausius equation
- The differential equation relating pressure to temperature in a system in
which two phases of a substance are in equilibrium. dp/dT = L/(T
V) where p is pressure; T is
temperature; L is the latent heat of the phase change; and V is the difference in volume of the phases.
Also called Clapeyron equation, Clausius-Clapeyron equation.
- Clapeyron equation = Clapeyron-Clausius
- Clausius-Clapeyron equation = Clapeyron-Clausius
- 1. The process of removing gas from a vacuum system or device by sorption or
- 2. In aeronautics, the process of improving external shape and smoothness
of an aircraft to reduce its drag.
- To restore a storage or memory device to
a prescribed state, usually that denoting zero. See reset.
- See meteorology,
- clipper = clipping
- clipping circuit
- A pulse-shaping network which
removes that part of a waveform which
tends to extend above, or below, a chosen voltage level. Also called
- The amount of insulation which will maintain normal skin temperature of
the human body when heat production is 50 kilogram-calorie per meter squared
per hour, air temperature is 70° F, and the air is still.
- One clo is roughly equivalent to the amount of insulation provided by
the average businessman's suit in a temperature climate.
- clock frequency
- The master frequency of
periodic pulses which
schedule the operation of a machine, as a computer.
- clock pulse
- A pulse
used for timing purposes. In pulse-code-modulation systems, a timing pulse
which occurs at the bit rate.
- closed ecological system
- A system that provides for the maintenance of life in an isolated living
chamber through complete reutilization of the material available, in
particular, by means of a cycle wherein exhaled carbon dioxide, urine, and
other waste matter are converted chemically or by photosynthesis into oxygen,
water, and food. Compare controlled-leakage
- closed-loop system
- A system in which the output is used
to control the input. See feedback
- closed-loop telemetry
- 1. A telemetry
system which is used as the indicating portion of a remote-control system.
- 2. A system used to check out test vehicle or telemetry performance
without radiation of radio-frequency energy.
- closed respiratory gas system
- A completely self-contained system within a sealed cabin, capsule, or
spacecraft that will provide adequate oxygen for breathing, maintain adequate
cabin pressure, and absorb the exhaled carbon dioxide and water vapor.
- closed system
- 1. In thermodynamics, a system so chosen that no transfer of mass takes
place across its boundaries; for example, a fluid parcel undergoing a
saturation-adiabatic process, as opposed to a pseudoadiabatic expansion. See
- 2. In mathematics, a system of differential equations and supplementary
conditions such that the values of all the unknowns (dependent variables) of
the system are mathematically determined for all values of the independent
variables (usually space and time) to which the system applies.
- 3. = closed
- 4. A system which constitutes a feedback loop
so that the inputs and controls depend on the resulting output. For example,
an automatic radar-controlled tracking system.
- closet approach
- 1. The event that occurs when two planets or other celestial
bodies are nearest to each other as they orbit about the sun or other primary.
- 2. The place or time of such an event.
- cloud rate
- The speed at which two bodies approach each other.
- cloud absorption
- The absorption
radiation by the water drops and water vapor within a cloud. Compare cloud
- For insolation
(incoming solar radiation), clouds absorb rather small fractions, particularly
of the shorter wavelengths. Even for depths of clouds of the order of 20,000
feet, measurements suggest absorptions of less than 30 percent, while layers
only 1000 to 2000 feet thick may absorb only about 5 percent. However, for
long wave terrestrial
radiation, even very thin layers of cloud act as almost complete
- cloud attenuation
- Usually, the reduction in intensity of microwave
radiation by clouds in the earth's atmosphere. For the centimeter wavelength
band, clouds produce Rayleigh
scattering. The attenuation is due largely to scattering, rather than to
absorption, for both ice and water clouds. See precipitation
attenuation. Compare cloud
- cloud band
- A broad band of clouds, from about 10 to 100 or more miles wide, and
varying in length from a few tens of miles to hundreds of miles. See cloud
- cloud chamber
- A device for observing the paths of ionizing
particles, based on the principle that supersaturated vapor condenses more
readily on ions than on neutral molecules.
- cloud physics
- A subdivision of physical
meteorology concerned with physical properties of clouds in the atmosphere
and the processes occurring therein.
- Cloud physics, broadly considered, embraces not only the study of
condensation and precipitation processes in clouds, but also radiative
transfer, optical phenomena, electrical phenomena, and a wide variety of
hydrodynamic and thermodynamic processes peculiar to natural clouds.
- cloud seeding
- Any technique carried out with the intent of adding to a natural cloud in
a planetary atmosphere certain substances that will altar the natural
development of that cloud.
- cloud street
- A line of cumuliform clouds frequently one cumulus element wide, but
ranging upward in width so that it is sometimes difficult to differentiate
between streets and bands. Typical dimensions are: axis spacing, 1 to 30
miles; length of cloud streets, 10 to 200 miles; cell spacing along axis, 1/2
to 2 miles. See cloud band.
- A flow rate
equal to 0.01 lusec.
- Two or more rocket
motors bound together so as to function as one propulsion unit.
- 1. Atmospheric
noise, extraneous signals, etc., which tend to obscure the reception of a
desired signal in a radio receiver, radarscope, etc.
- As compared with interference, clutter refers more particularly
to unwanted reflections on a radar plan
position indicator, such as ground return, but the terms are often used
- 2. = window.
- CMa, C Maj
- International Astronomical Union abbreviations for Canis Major. See
- CMi, C Min
- International Astronomical Union abbreviations for Canis Minor. See
- Cnc, Canc
- International Astronomical Union abbreviations for Cancer. See constellation.
- 1. A prefix meaning 90° minus the value with which it is used. Thus, if
the latitude is 30°, the colatitude is 90° - 30° = 60°.
- 2. A prefix meaning in common, as in coaxial, having a common axis.
- coaltitude = zenith
- A memory feature on a radar which, when
activated, causes the range and angle systems to continue to move in the same
direction and at the same speed as that required to track an original target.
- Coast is used to prevent lock-on to a
stronger target if approached by the target being tracked.
- coasting flight
- The flight of a rocket between
thrust cutoff of one stage and ignition of another, or between burnout and
summit altitude or maximum horizontal range.
- coated optics
- Optical elements (lenses, prisms, etc.) which have their surfaces covered
with a thin transparent film to minimize reflection and loss of light in the
- coaxial cable
- A form of waveguide
consisting of two concentric conductors insulated from each other.
- codan (abbr) = carrier operated
- A device which silences a receiver except when a carrier signal is being
- 1. A system of symbols or signals for
and the rules for associating them.
- 2. The set of characters resulting from the use of a code as defined in
- 3. Specifically, to translate a problem to a routine
expressed in machine language for a specific computer.
- 4. To express given information by means of a code, to encode.
- Ninety degrees minus the declination.
When the declination and latitude are of the same name, codeclination is polar
distance measured from the elevated
- coded decimal digit
- In computer operation, a decimal
digit expressed in a code, usually a four-digit binary
- The arrangement in a coded form, usually acceptable to a specific computer, of
the instructions for the operations necessary to solve a problem.
- coefficient (abbr coeff)
- 1. A number indicating the amount of some change under certain specified
conditions, often expressed as a ratio.
- For example, the coefficient of linear expansion of a substance is the
ratio of its change in length to the original length for a unit change of
temperature from a standard.
- 2. A constant in an algebraic equation.
- 3. One of several parts which combine to make a whole, as the maximum
deviation produced by each of several causes.
- coefficient of barotropy.
- See barotropy.
- coefficient of compressibility
- The relative decrease of the volume of a gaseous system with increasing
pressure in an isothermal
process. This coefficient is
-(1/V)(V/ p)Twhere V is the
volume; p is the pressure; and T is the temperature. The
reciprocal of this quantity is the bulk
modulus. Also called compressibility. Compare coefficient
of thermal expansion, coefficient
- coefficient of diffusion = diffusivity.
- coefficient of heat conduction = thermal
- coefficient of molecular viscosity = dynamic
- coefficient of mutual diffusion
- A quantity in the kinetic theory of gases which measures the tendency of
gases to diffuse into one another in nonturbulent flow.
- This diffusion coefficient is a property of the gases in question and
of the assumed nature of the molecular impacts in the diffusion
process. For rigid, perfectly elastic, spherical molecules the coefficient of
mutual diffusion d1,2 is, in square centimeters per second,
n is Loschmidt number (the number of molecules per cubic centimeter);
1, 2 and m1, m2 are
the effective molecular diameters and masses of the two gases, respectively;
T is the temperature,°K; and k is Boltzmann constant.
- coefficient of tension
- The relative increase of pressure of a system with increasing temperature
in an isochoric
process. In symbols this quantity is
(1/p)(p/ T)Vwhere p is
pressure; T is temperature; and V is volume. Compare coefficient
of compressibility, coefficient
of thermal expansion.
- coefficient of thermal conduction = thermal
- coefficient of thermal conductivity =thermal
- coefficient of thermal expansion
- The ratio of the change of length per unit length (linear), or
change of volume per unit volume (voluminal), to the change of
- coefficient of viscosity= dynamic
- In radar, a relation between two wave trains
such that, when they are brought into coincidence, they are capable of
producing interpretable interference phenomena.
- This is limited to those wave trains which have fixed or slowly varying
phase relationships with each other.
- In contract are the rapid interference phenomena produced by the
superposition of the more or less randomly scattered waves from
- 1. Of electromagnetic radiation, being in phase, so
that waves at various points in space act in unison, as in a laser
producing coherent light.
- 2. Having a fixed relation between frequency and phase of input and output
- coherent carrier
- A carrier
wave derived from a continuous-wave signal in such a way that its frequency and
phase have a
fixed relationship to the frequency and phase of the reference signal.
- coherent echo
- A radar echo whose phase and amplitude at
a given range remain relatively constant.
- Hills, buildings, and slowly moving point targets such as ships are
examples of objects which produce coherent radar echoes. Volume targets (such
as clouds and precipitation) give noncoherent echoes. The classification of an
echo as coherent or noncoherent is closely related to the spatial resolution
(beam width) of the radar or the volume occupied by the radar pulse. Thus,
small atmospheric inhomogeneities which give rise to noncoherent echoes, would
give coherent echoes if the radar volume were reduced in size to the order of
magnitude of the inhomogeneities themselves.
- coherent oscillator (abbr Coho)
- An oscillator
which provides a reference by which the radio frequency phase difference
of successive received pulses may be recognized. See coherent
- coherent radar
- A type of radar that
employs circuitry which permits comparison of the phase of
successive received target signals.
- coherent reference
- The reference signal, usually
of stable frequency, to which other signals are phase-locked
to establish coherence
throughout a system.
- coherent transponder
- A transponder,
the output signal of which is coherent with the input signal.
- Coho (abbr) = coherent
- coincidence circuit
- An electronic circuit that
produces a usable output pulse
only when each of two or more input circuits
receive pulses simultaneously or within an assignable time interval.
- coincidence counter
- A device using ionization
counters and coincidence
circuits to count and determine the direction of travel of ionized particles,
particularly cosmic rays.
- coincident-current magnetic core
- A binary
magnetic core in which information is stored as the result of current
flowing simultaneously in two or more independent windings.
- Usually a number of cores are arranged in the form of a matrix.
- Col, Colm
- International Astronomical Union abbreviations for Columba. See constellation.
- Ninety degrees minus the latitude.
- cold cathode
- A cathode whose operation does not depend on its temperature being above
the ambient temperature.
- cold-cathode gage = cold-cathode
- cold-cathode ionization gage
- A ionization
gage (vacuum gage) in which the ions are produced by a discharge between
two electrodes, both near room temperature. The discharge usually takes place
in the presence of a magnetic field which lengthens the path of the electrons
between cathode and anode.
- One form of gage is a transparent tube in which the color and form of a
cold-cathode discharge, without the presence of a magnetic field, give an
indication of the pressure and the nature of the gas. The Philips ionization
gage, or Penning gage, is a cold-cathode ionization gage in which a magnetic
field is used. Various modifications of the Penning gage are named after the
inventors, and certain types are referred to as magnetron vacuum gages.
- cold-flow test
- A test of a liquid
rocket without firing it to check or verify the efficiency of a propulsion
subsystem, providing for the conditioning and flow of propellants
(including tank pressurization, propellant loading, and propellant feeding).
- cold-pressor test
- A test for measuring the response of heart and blood pressure to the
stress of plunging an extremity (foot or hand) into ice water.
- The normal response is an increase in both heart rate and blood
- cold working
- Deforming metal plastically at a temperature lower than the
- An aircraft
having an annular (barrel-shaped) wing, the engine and body being mounted
within the circle of the wing.
- 1. To render parallel, as rays of light.
- 2. To adjust the line of
sight of an optical instrument, such as a theodolite, in proper relation
to other parts of the instrument.
- collimation error
- The angular error in magnitude and direction between two nominally
parallel lines of sight; specifically, the angle by which the line of
sight of an optical instrument or radar differs from what it should be.
- collimation tower
- A tower on which are mounted a visual and a radio target for use in
checking the electrical axis of an antenna.
- An optical device which renders rays of light parallel.
- An encounter between two particles
that changes their existing momentum and
energy conditions. See elastic
- The products of the collision may or may not be the same as the
precollision particles. The collision may be actual contact or the close
approach and deflection of the particles.
- collision broadening
- In spectroscopy, the broadening or spreading of an emission
line, due to the interruption of the radiating process by a collision of
the radiator with another particle.
- In the case of cyclotron
radiation, the collision will actually change the phase of the radiation.
For many collisions, this has the effect of broadening the observed
frequencies by an amount equal to the collision
- collision cross section
- See cross
section. See also elastic
- collision frequency = collision
- collistion frequency per molecule = collision
- collision frequency per unit volume
- The number of collisions between molecules in a gas per unit volume per
- collision parameter
- 1. In orbit computation, the distance between a center of attraction of a
force field and the extension of the velocity vector of a moving object at
a great distance from the center.
- 2. In gas dynamics and atomic physics, any of several parameters, such as
rate, mean free
path, etc., which provide a measure of the probability of collision.
- collision rate
- The average number of collisions per second suffered by a molecule or
moving through a gas. Also called collision frequency.
- See colloidal
- colloidal dispersion = colloidal
- colloidal suspension = colloidal
- colloidal system
- An intimate mixture of two substances one of which, called the
dispersed phase (or colloid ) is uniformly distributed in a
finely divided state through the second substance, called the dispersion
medium (or dispersing medium ). The dispersion medium may be a gas,
a liquid, or a solid, and the dispersed phase may also be any of these, with
the exception that one does not speak of a colloidal system of one gas in
another. Also called colloidal dispersion, colloidal suspension.
- A system of liquid or solid particles colloidally dispersed in a gas is
called an aerosol. A system of solid substance or water-insoluble
liquid colloidally dispersed in liquid water is called a hydrosol.
There is no sharp line of demarcation between true solutions and colloidal
system on the one hand, or between mere suspensions and colloidal systems on
the other. When the particles of the dispersed phase are smaller than about 1
millimicron in diameter, the system begins to assume the properties of a true
solution; when the particles dispersed are much greater than 1 micron,
separation of the dispersed phase from the dispersing medium becomes so rapid
that the system is best regarded as a suspension.
- International Astronomical Union abbreviation for Columba. See constellation.
- Applied to a photographic emulsion sensitive only to blue, violet, and
- color equation
- In astronomy, a measure of the color sensitivity of a method of
observation, equal to the color index
of a class K0 star.
- color excess (symbol E)
- The difference between the apparent color
index of a star and its true color index as computed for its stellar type.
- Color excess is a measure of space
- color index (symbol C)
- Of a star, the numerical difference between the apparent photographic
magnitude and the apparent photovisual
magnitude mpv or
C = mpg - mpv
- The color index is zero for class A0 stars of magnitudes between 5.5
and 6.5; it is positive for red stars and negative for bluish stars. Various
other color indices can be formed by using apparent magnitudes measured in
other systems. Thus, the intrinsic color index is apparent photographic
magnitude minus apparent ultraviolet magnitude.
- color sensitive
- Referring to a photographic emulsion which is not colorblind.
- An emulsion sensitive not only to blue, violet, and ultraviolet, but
also to yellow and green, is called orthochromatic; if sensitive to red as
well, it is called panchromatic.
- color temperature
- 1. An estimate of the temperature
of an incandescent body, determined by observing the wavelength
at which it is emitting with peak intensity (its color) and using that
wavelength in Wien law.
- If such a body were an ideal black body, the temperature so estimated
would be its true temperature and would also agree with its effective
temperature; but for actual bodies, the color temperature is generally
only an approximate value. Thus, the sun's color temperature is about 6100° K,
a few hundred degrees hotter than most approximations of its effective
- 2. The temperature to which a black body
radiator must be raised in order that the light it emits may match a given
light source in color. [Usually expressed in Kelvin (°K).]
- Columba (abbr Col, Colm)
- See constellation.
- In a structure, a body whose function is to carry compression
loads to its longest dimension.
- Com, Coma
- International Astronomical Union abbreviations for Coma Berenices.
- International Astronomical Union abbreviations for Coma Berenices.
- 1. The gaseous envelope that surrounds the nucleus of a comet.
- 2. In an optical system, a result of spherical aberration in which a point
source of light, not on the axis, has a blurred, comet-shaped image.
- Coma Berenices (abbr Com, Coma)
- See constellation.
- combination coefficient
- A measure of the specific rate of disappearance of small ions
due to either (a) union with neutral Aitken
nuclei to form new large ions, or (b) union with large ions of opposite
sign to form neutral Aitken nuclei.
- combined error
- A term used to specify the largest possible error of an instrument in the
presence of adding or interacting effects.
- Generally applied to the largest error due to the combined effect of
nonlinearity and hysteresis.
- combustion chamber (symbol c used as a subscript)
- Any chamber for the combustion of fuel, specifically that part of the rocket
engine in which the combustion of propellants
takes place at high pressure. Also called chamber, firing chamber.
- The combustion chamber plus the diverging section of the nozzle comprise
the rocket thrust chamber.
- combustion-chamber liner = inner
- combustion efficiency
- The efficiency with which fuel is burned,
expressed as the ratio of the actual energy released by the combustion to the
energy of the fuel.
- combustion instability
- Unsteadiness or abnormality in the combustion
of fuel, as may occur, e.g., in a rocket
- combustion wave
- A zone of burning propagated through a combustible medium.
- combustor = combustion
- comes (plural, comites)
- The smaller star in a binary system.
Also called companion.
- A luminous member of the solar
system composed of a head, or coma, and often
with a spectacular gaseous trail extending a great distance from the head.
- The orbits of comets are highly elliptical.
- A signal
which initiates or triggers an action in the device which receives the signal.
In computer operations also called instruction.
- command control
- A system whereby functions are performed as the result of a transmitted signal.
- command destruct
- A command
control system that destroys a flightborne test rocket, actuated
on command of the range safety officer whenever the rocket performance
indicates a safety hazard.
- command guidance
- The guidance of a
spacecraft or rocket by means of electronic signals sent to
receiving devices in the vehicle.
- common item
- An item of supply used in two or more systems,
subsystems, or pieces of support equipment, including related components
- communications satellite
- A satellite
designed to reflect or relay electromagnetic signals used for communication.
- Sequential sampling, on a repetitive timesharing basis, of multiple data
sources for transmitting or recording, or both, on a single channel.
- commutation rate
- Number of commutator
inputs sampled per second.
- A device used to accomplish time
division multiplexing by repetitive sequential switching.
- The smaller body in a physical double-star system. See binary
star. Also called comes.
- companion body
- A nose cone, last-stage rocket, or other body that orbits along with an
- In computer operations, a device or circuit for comparing information from
- 1. An instrument for indicating a horizontal reference direction,
specifically a magnetic compass.
- 2. Referring to or measured from compass
- compass meridian
- See meridian.
- compass north
- The direction north as indicated by a magnetic
compass; the reference direction for measurement of compass directions.
- 1. A characteristic ascribed to a major subsystem that indicates it
functions well in the overall system.
- 2. Also applied to the overall system with reference to how well its
various subsystems work together, as in the vehicle has good compatibility.
- 3. Also applied to materials which can be used in conjunction with other
materials which can be used in conjunction with other materials and not react
with each other under normal operating conditions.
- compensation signals
- In telemetry, a signal recorded
on a tape, along with the data and in the same track as the data, used during
the playback of data to correct electrically the effects of tape-speed errors.
- In computer terminology, to assemble the
necessary subroutines into a main routine for a
- 1. An angle equal to 90° minus a given angle.
- Thus, 50° is the complement of 40°, and the two are said to be
complementary. See explement.
- 2. The true complement of any quantity in positional notation, i.e., the
quantity which, when added to the first quantity, gives the least quantity
containing one more place.
- 3. The base-minus-one complement of any quantity in positional notation;
i.e., the quantity which, when added to the first quantity, gives the largest
quantity containing the same number of places.
- In many computing machines a negative quantity is represented as a
complement of the corresponding positive quantity.
- complementary angle = complement.
- In Boolean
algebra, an operation in which items are described by stating that they do
not belong to a particular class or classes. See NOT
- In computers, a device which performs a function corresponding to the
operation of complementation.
- 1. Short for launch
complex, as in Complex 25B at Cape Kennedy.
- 2. Pertaining to a magnitude composed of a real number and an imaginary
- complexity units
- In reliability studies of electronic devices, an approximate figure of
merit for complexity based on the sum of the number of tubes plus the number
of relays in a unit or system. The total number of parts is roughly 10 times
the number of complexity units.
- An article which is a self-contained element of a complete operating
unit and performs a function necessary to the operation of that unit.
- composite materials
- Structural materials of metals, ceramics, or
plastics with built-in strengthening agents which may be in the form of
filaments, foils, powders, or flakes of a different compatible material.
- composite propellant
- A solid
rocket propellant consisting of a fuel and an oxidizer neither of which
would burn without the presence of the other.
- compound centripetal acceleration = coriolis
- compressed air illness = caisson
- 1. The property of a substance, as air, by virtue of which its density
increases with increase in pressure.
- 2. = coefficient
- In aerodynamics, this property of the air is manifested especially at
high speeds (speeds approaching that of sound and higher speeds).
Compressibility of the air about an aircraft may give rise to buffeting,
aileron buzz, shifts in trim, and other phenomena not ordinarily encountered
at low speeds, known generally as compressibility effects.
- compressibility burble
- A region of disturbed flow, produced by, and rearward of, a shock wave.
- compressible flow
- In aerodynamics, flow at speeds
sufficiently high that density changes in the fluid cannot be neglected.
- 1. = ellipticity.
- 2. More generally, the act of compressing, pressing together; as in
compression waves, compression ratio.
- compressional wave
- In acoustics, a wave in an elastic
medium which causes an element of the medium to change its volume without
Mathematically, a compressional wave is one whose velocity field has zero
curl. Also called compression wave.
- A compressional plane wave is a longitudinal
- A machine for compressing air or other fluid.
- Compressors are distinguished (1) by the manner in which fluid is
handled or compressed, as the axial
compressor; or (2) by the number of stages, as the multistage
compressor. See individual entries on the different types.
- compressor blade
- Either a rotor blade or a stator blade in an axial-flow compressor;
sometimes used restricitevly (and ambiguously) for a compressor rotor blade.
- Compton effect
- The decrease in frequency and
increase in wavelength
of X-rays or
rays when scattered by free electrons. Also called Compton recoil
- Compton electron
- An orbital electron of an
atom which has been ejected from its orbit as a result or an impact by a
high-energy quantum of
radiation (X-ray or gamma ray). Also called Compton recoil electron.
- Compton recoil effect = Compton
- Compton recoil electron = Compton
- Compton wavelength (symbol c)
- Of a particle, the distance h/mc, where h is the Planck
constant, m is the mass of the particle, and c is the velocity
- The Compton wavelength of the electron (symbol c) is 2.4261 x 10-10
centimeter; of the proton (symbol cp) is 1.32140 x 10-13
- 1. A machine for carrying out calculations and performing specified
transformations on information. Also called computing machinery.
- 2. One who computes, or who operates a computer.
- computing efficiency
- Of a computer, the percentage of the successful computation time during a
defined period to the total time in that period. Also called operating
- computing machinery
- Machinery which can take in, give out, and store information, and also
perform arithmetic and logical
operations with the information. Usually called computer.
- 1. The physical process by which a vapor becomes a liquid or solid; the
opposite of evaporation.
- 2. Specifically, in meteorology, the transformation from vapor to liquid.
- condensation coefficient
- The ratio of condensation
rate to impingement
- condensation nucleus
- 1. A particle,
either liquid or solid, upon which condensation
of vapor begins.
- 2. Specifically, in meteorology, a particle upon which condensation of
water begins in the atmosphere.
- condensation rate
- The number per square centimeter per second at which molecules condense on
- condensation shock = condensation
- condensation shock wave
- A sheet of discontinuity associated with a sudden condensation
and fog formation in a field of flow. It occurs,
e.g., on a wing, where a rapid drop in pressure causes the temperature to drop
considerably below the dew point. Also called condensation shock.
- condensation trail
- A visible trail of condensed water vapor or ice particles left behind an
aircraft, an airfoil, etc. in motion through the air. Also called a
contrail or vapor trail.
- There are three kinds of condensation trails: the aerodynamic type,
caused by reduced pressure of the air in certain areas as it flows past the
aircraft; the convection type, caused by the rising of air warmed by an
engine; and the engine-exhaust, or exhaust-moisture, type, formed by the
ejection of water vapor from an engine into a cold atmosphere.
- 1. In electricity, the ratio of the current flowing through an electric
circuit to the difference of potential between the ends of the circuit, the
reciprocal of resistance.
- 2. In vacuum systems, the throughput
Q under steady-state conservative conditions divided by the measured
difference in pressure p between two specified cross sections inside a
G = Q/(p1-p2).
- The transfer of energy within and through a conductor by means of internal
particle or molecular activity and without any net external motion.
- Conduction is to be distinguished from convection
(of heat) and radiation (of
all electromagnetic energy).
- conduction band
- A range of states in the energy
spectrum of a solid in which electrons can
- conductive equilibrium = isothermal
- 1. The ability to transmit, as electricity, heat, sound, etc.
- 2. A unit measure of electrical conduction; the facility with which a
substance conducts electricity, as represented by the current density per unit
electrical-potential gradient in the direction of flow.
- Electrical conductivity is the reciprocal of electrical resistivity
and is expressed in units such as mhos (reciprocal ohms) per centimeter. It is
an intrinsic property of a given type of material under given physical
conditions (dependent mostly upon temperature). Conductance,
on the other hand, varies with the dimensions of the conducting system, and is
the reciprocal of the electrical resistance.
- A substance or entity which transmits electricity, heat, sound, etc.
- 1. A geometric configuration having a circular bottom and sides tapering
off to an apex (as in nose cone).
- 2. A type of light-sensitive cell in the retina. Cones are involved in
color vision, high visual acuity, and photopic
- cone of escape
- A hypothetical cone in the exosphere,
directed vertically upward, through which an atom or molecule would
theoretically be able to pass to outer space without a collision, that is, in
which the mean free
path is infinite. See fringe
- Such a cone would open wider with increasing altitude above the critical
level of escape, and would be nonexistent below the critical level of
- confidence interval
- In statistics, a range of values which is believed to include, with a
preassigned degree of confidence (confidence
level), the true characteristic of the lot or universe a given percentage
of the time.
- For example: 95-percent confidence limits for a sample of 10 with a
ratio of successes to total number tested of 0.9 (9 successes and 1 failure)
would be 0.54 to 1.0. That is, even with an observed success ratio of 0.9 (90
percent) the best that can be said is that the true ratio lies between 0.54
(54 percent) and 1.0 (100 percent) an estimated 95 percent of the time.
- confidence level
- In statistics, the degree of desired trust or assurance in a given result.
- A confidence level is always associated with some assertion and
measures the probability
that a given assertion is true. For example, it could be the probability that
a particular characteristic will fall within specified limits, i.e., the
chance that the true value of P lies between P = a and P = b. See confidence
- confidence limits
- In statistics, the upper and lower extremes of the confidence
- 1. Relative position or disposition of various things, or the figure or
pattern so formed.
- 2. A geometric figure, usually consisting principally of points and
- 3. = planetary
- 4. A particular type of a specific aircraft, rocket, etc., which differs
from others of the same model by virtue of the arrangement of its components
or by the addition or omission of auxiliary equipment as long-range
configuration, cargo configuration.
- Some writers use constellation as a synonym for
configuration in referring to the relative positions of spacecraft to
each other, as in a rendezvous maneuver, or to celestial bodies. This usage
should be discouraged.
- The rate at which adjacent flow is converging
along an axis oriented normal to the flow at the point in question. It is the
opposite of difluence.
- Having correct angular representation.
- 1. A curve formed by the intersection of a plane and a right circular
cone. Originally called conic section.
- The conic sections are the ellipse, the parabola, and
curves that are used to describe the path or bodies moving in space. The
circle is a special case of the ellipse, an ellipse with an eccentricity of
The conic is the locus of all points the ratio of whose distances
from a fixed point, called the focus, and a fixed line, called the
directrix, is constant.
- 2. In reference to satellite orbital parameters, without consideration of
the perturbing effects of the actual shape or distribution of mass of the
- Thus, conic perigee is the perigee the satellite would have if
all the mass of the primary were concentrated at its center.
- conical beam
- The radar
beam produced by conical
- This type of beam has an advantage over that produced by a single
radiating element placed at the focus of a parabolic reflector in that much
greater angular accuracy is possible in locating targets.
- conical scanning
- Scanning in which the direction of maximum radiation generates a cone
whose vertex angle is of the order of the beam width.
Such scanning may be either rotating or nutating, according as the direction
of polarization rotates or remains unchanged.
- conic section
- The original name for conic.
- 1. The situation of two celestial
bodies having either the same celestial
longitude or the same sidereal hour angle. Compare opposition,
- A planet is at superior conjunction if the sun is between it and the
earth; at inferior conjunction if it is between the sun and the earth.
- 2. The time at which conjunction, as defined in sense 1, takes place.
- conservation of angular momentum
- The principle that absolute angular
momentum is a property which cannot be created or destroyed by can only be
transferred from one physical system to
another through the agency of a net torque on the system. As a consequence,
the absolute angular momentum of an isolated physical system remains constant.
- The principle of conservation of angular momentum can be derived from
the Newton second law of motion.
- conservation of energy
- The principle that the total energy of an
isolated system remains constant if no interconversion of mass and energy
- This principle takes into account all forms of energy in the system; if
therefore provides a constraint on the conversions from one form to another.
- conservation of mass
- The principle in Newtonian
mechanics which states that mass cannot be created or destroyed but only
transferred from one volume to another. See continuity
- conservation of momentum
- The principle that in the absence of forces absolute momentum is a
property which cannot be created or destroyed. See Newton
laws of motion.
- An array of controls and indicators for the monitoring and control of a
particular sequence of actions, as in the checkout of a rocket, a countdown
action or a launch procedure.
- A console is usually designed around desk-like arrays. It permits the
operator to monitor and control different activating instruments, data
recording instruments, or event sequences.
- constant-level balloon
- A balloon designed to float at a constant-pressure level. Also called
constant-pressure balloon. See skyhook
- In one design for such a system, a pressure switch actuates a valve
which controls the release of ballast so as to maintain flight above a
selected pressure level until the supply of ballast is exhausted.
design is a simple nonextensible envelope capable of withstanding a
differential of pressure, higher inside than out. It is inflated so that the
smaller night-time pressure of the gas still fully extends the envelope. Such
a superpressure balloon will keep essentially constant level until
enough gas diffuses out of it to allow diurnal changes in volumes.
- constant of aberration
- The maximum aberration
of a star observed from the surface of the earth, 20.49 seconds of arc.
- The maximum occurs at the time the direction of motion of the earth in
its orbit is at right angles to a line from the earth to the star.
- constant of gravitation = Newtonian
universal constant of gravitation.
- constant of nutation
- See nutation,
- constant-pressure balloon = constant-level
- Originally a conspicuous configuration of stars; now a region of the
celestial sphere marked by arbitrary boundary lines.
- The genitive form of constellation names is used in star names and
numbers such as Bayer name
number. Table V
lists the constellations.
- constituent day
- The duration of one rotation of the earth on its axis, with respect to an
astre fictif, a fictitious star representing one of the periodic elements in
the tidal forces. It approximates the length of a lunar or solar day.
- construction weight
- The weight of a rocket exclusive
of propellant, load, and crew, if any. Also called structural weight.
- continuity equation
- In a steady-flow
process, the mathematical statement of the principle of the conservation
of mass by equating the flow at any section x, wx to the
flow at any section y, or wx= wy.
- continuous absorption
- See absorption
- continuous-flow system
- An oxygen system in which the oxygen flows during both inspiration and
expiration by the individual.
- continuous spectrum
- 1. A spectrum in
which wavelengths, wave numbers, and frequencies are represented by the
continuum of real numbers or a portion thereof, rather than by a discrete
sequence of numbers. See discrete
- 2. For electromagnetic
radiation, a spectrum that exhibits no detailed structure and represents a
gradual variation of intensity with wavelength from one end to the other, as
the spectrum from an incandescent solid. Also called continuum, continuum
- 3. For particles, a
spectrum that exhibits a continuous variation of the momentum or energy.
- continuous variable
- A variable which can assume any value within a defined range.
- continuous-wave radar
- A general species of radar
transmitting continuous waves, either modulated or unmodulated. The simplest
form transmits a single frequency and detects only moving targets by the
Doppler effect. This type of radar determines direction but usually not range.
Also called CW radar. Compare pulse
- Two advantages of CW radar are the narrow bandwidth and low power
required. Range information may be obtained by some form of modulation, e.g.,
frequency modulation, pulse modulation.
- continuous waves (abbr CW)
- Waves, the
successive oscillations of which are identical under steady-state conditions.
- 1. Something which is continuous, which has no discrete parts, as the
continuum of real numbers as opposed to the sequence of discrete
integers, as the background continuum of a spectrogram
due to thermal radiation.
- 2. = continuous
- continuum flow
- See rarefied
- continuum radiation = continuous
- contrail = condensation
- 1. In general, the degree of differentiation between different tones in an
- Where the degree is slight, the image is said to be flat. Where the
difference is marked, it is said to be contrasty.
- 2. The difference in luminance between two portions of the visual field
usually expressed as:
c = (background - test field)/background * 100%
- Since this ratio can be negative for nearly black targets at close
range, and since the sign of the contrast has no psycho-physical significance,
it is conventional to use only its absolute value. See threshold
- contrast threshold = threshold
- A vane that reverses or neutralizes rotation of a flow. Also called
- 1. A lever, switch, cable, knob, push-button, or other device or apparatus
by means of which direction, regulation, or restraint is exercised over
- 2. In plural (a) A system or assembly of levers, gears, wheels, cables,
boosters, valves, etc., used to control the attitude, direction movement,
power, and speed of an aircraft, rocket spacecraft, etc. (b) Control surfaces
- 3. Sometimes capitalized. An activity or organization that directs or
regulates an activity. See central
- 4. Specifically, to direct the movements of an aircraft or rocket with
particular references to changes in attitude and speed. Compare guidance.
- control feel
- The impression of the stability and control of an aircraft that a pilot
receives through the cockpit controls,
either from the aerodynamic
forces acting on the control surfaces or from forces simulating these
aerodynamic forces. See artificial
- The capability of an aircraft, rocket, or other vehicle to respond to control,
especially in direction or attitude.
- controlled environment
- The environment
of any object, such as an instrument, a man, or an unlaunched rocket, in which
effects such as humidity, pressure, temperature, etc., are maintained at
- controlled-leakage system
- A system that provides for the maintenance of life in an aircraft or
spacecraft cabin by a controlled escape of carbon dioxide and other waste from
the cabin, with replenishment provided by stored oxygen and food. Compare closed
- control rocket
- A vernier
or other such rocket, used to change the attitude of, guide, or make small
changes in the speed of a rocket, spacecraft, or the like.
- control unit
- The part of a computer which
causes the arithmetic
unit, storage, and
transfer of a computer to operate in proper sequence.
- control vane
- A movable vane used for control,
especially a movable air vane or jet vane on a
rocket, used to control flight attitude.
- 1. In general, mass motions within a fluid resulting
in transport and mixing of the properties of that fluid. Compare conduction,
- 2. Specifically, in meteorology, atmospheric motions that are
predominantly vertical. Compare advection.
- convective atmosphere = adiabatic
- 1. The contraction of a vector field; also, a precise measure thereof.
- Mathematically, convergence is negative divergence, and the latter term
is used for both. (For mathematical treatment, see divergence.)
- 2. The property of a sequence or series of numbers or functions which
ensures that it will approach a definite finite limit.
- A series representation of a mathematical function exhibits convergence
if the sum of the terms of the series approaches the value of the function
more closely as more terms of the series are taken, the two agreeing in the
limit of an infinite number of terms.
- 3. Decrease in area or volume.
- conversion device
- In computer terminology, any device for changing the manner of
representing information. Also called a converter.
- In computer terminology, (a) to change the manner of representing
information, e.g., from analog to digital; (b) to translate the medium of
conveying or storing information, e.g., from punched cards to magnetic tape;
(c) to change numeric
information from one notation to
- 1. A rotary device for changing alternating current to direct current.
- A static device for this purpose is called a rectifier. A device for
changing direct current to alternating current is called an inverter.
- 2. A transducer whose output is a different frequency from its input.
- 3. In computer terminology = conversion
- A hybrid form of heavier-than-air aircraft that is capable, by virtue of
one or more horizontal rotors or units acting as rotors, of taking off,
hovering, and landing as, or in a fashion similar to, a helicopter, and once
aloft, and moving forward, capable, by means of a mechanical conversion of one
sort or another, of flying purely as a fixed-wing aircraft, especially in its
higher speed ranges.
- coolant ( symbol c used as subscript )
- A liquid
or gas used to
cool something, as a rocket combustion chamber.
- This word is used in many self-explanatory compounds, which include:
coolant chamber, coolant gallery, coolant hose, coolant jacket, coolant
passage, coolant pump, coolant radiator.
- cooled-tube pyrometer
- A thermometer
for high-temperature flowing gases that uses a liquid-cooled tube inserted in
the flowing gas; gas temperature is deduced from the law of convective heat
transfer to the outside of the tube and from measurement of the mass flow rate
and temperature rise of the cooling liquid.
- See radiator,
- cooling power
- In the study of human bioclimatology, one of several parameters devised to
measure the air's cooling effect upon a human body.
- One of a set of measures defining a point in space.
- If the point is know to be on a given line, only one coordinate is
needed; if on a surface, two are required; if in space, three. Cartesian
coordinates define a point relative to two intersecting lines, called axes. If
the axes are perpendicular, the coordinates are rectangular; if not
perpendicular, they are oblique coordinates. A three-dimensional system of
Cartesian coordinates is called space coordinates. Polar coordinates define a
point by its distance and direction from a fixed point called the pole.
Direction is given as the angle between a reference radius
vector and a radius vector to the point. If three dimensions are involved,
two angles are used to locate the radius vector. Space-polar coordinates
define a point on the surface of a sphere by (1) its distance from a fixed
point at the center, the pole; (2) the colatitude or angle between the polar
axis (a reference line through the pole) and the radius vector (a straight
line connecting the pole and the point); and (3) the longitude or angle
between a reference plane through the polar axis and a plane through the
radius vector and the polar axis. Spherical coordinates define a point on a
sphere or spheroid by its angular distances from a primary great circle and
from a reference secondary great circle. Geographical or terrestrial
coordinates define a point on the surface of the earth. Celestial coordinates
define a point on the celestial sphere.
summarizes the terms used in four geocentric celestial coordinate systems and
the terrestrial (geographic) coordinate system and indicates the analogous
terms under each system.
- coordinate axes.
- See Cartesian
- coordinate line
- See curvilinear
- coordinate planes
- See Cartesian
- coordinate surface
- See curvilinear
- coordinate system
- Any scheme for the unique identification of each point of a given continuum.
The geometry of the system is a matter of convenience determined by the
boundaries of the continuum or by other considerations. Also called
- To reproduce information without changing it.
- Cor A
- International Astronomical Union abbreviation for Corona Austrina.
- Cor B
- International Astronomical Union abbreviation for Corona Borealis.
- coriolis acceleration
- An acceleration
of a particle moving in a relative
coordinate system. The total acceleration of the particle, as measured in
coordinate system, may be expressed as the sum of the acceleration within
the relative system, the acceleration of the relative system itself, and the
- Physically, coriolis acceleration may be considered as coming from the
conservation of momentum in a body moving in a direction not parallel to the
axis of rotation of the relative system.
acceleration comes from the differentiation of terms containing the angular
velocity in the expression for the absolute
velocity of the particle.
In the case of the earth, moving with angular
velocity , a particle moving relative to the
earth with velocity v has the coriolis acceleration 2 * v. If Newton laws are to be applied in the
relative system, the coriolis acceleration and the acceleration of the
relative system must be treated as forces. See apparent
- coriolis correction
- A correction applied to an assumed position, celestial line of
position, celestial fix, or to a computed or observed altitude to allow
for apparent acceleration due to coriolis
- coriolis effects
- The physiological effects (nausea, vertigo, dizziness, etc.) felt by a
person moving radially in a rotating system, as a rotating space station.
- coriolis force
- An inertial force on a moving body, or particles, produced by the movement
of the masses involved, perpendicular to the axis of the primary rotating
system. Also called compound centrifugal force, deflecting force. See
- Such a force is required if Newton Laws are to be applied in the
- coriolis parameter
- Twice the component of the earth's angular velocity about the local
vertical, 2 sin , where is the
angular speed of the earth and is the latitude.
- corner reflector
- In radar, three conducting surfaces mutually intersecting at right angles
designed to return electromagnetic radiations toward their sources and used to
render a position more conspicuous to radar
- 1. The outer visible envelope of the sun. Also called solar corona.
- It is observed at solar eclipse or with the coronagraph.
The shape of the corona varies during the sunspot cycle. At sunspot minimum
the corona has large extensions along the sun's equator, with short brushlike
tufts near the poles. At sunspot maximum the equatorial extensions are much
smaller and the corona is more regular in shape. The temperature of the corona
appears to be in the vicinity of 1,000,000° K.
- 2. The extremely tenuous outer atmosphere of the sun now known to extend
past the earth's orbit.
- 3. A set of one or more prismatically colored rings of small radii,
concentrically surrounding the disk of the sun, moon, or other luminary when
veiled by a thin cloud.
- The corona is due to diffraction
by numerous water drops. It can be distinguished from the relatively common
halo of 22° by the much smaller angular diameter of the corona, which is often
only a few degrees, and by its color sequence, which is from blue inside to
red outside, the reverse of that in the 22° halo.
- 4. See corona
- 5. See aurora.
- 6. See geocorona.
- Corona Australis = Corona Austrina (abbr CrA, Cor
A) . See constellation
- Corona Borealis (abbr CrB, Cor B)
- See constellation.
- corona discharge
- A luminous, and often audible, electric
discharge the is intermediate in nature between a spark
discharge (with, usually, its single discharge channel) and a point
discharge (with its diffuse, quiescent, and nonluminous character). Also
called brush discharge, St. Elmo's fire, corposant.
- An instrument for photographing the corona and prominences
of the sun at times other than at solar eclipse. An occulting disk is used to
block out the image of the body of the sun in the focal plane of the objective
lens. The light of the corona passes the occulting disk and is focused on a
- Great care must be taken to avoid light scattered from the atmosphere
and the lenses, and from reflections in the tube of the instrument. The
coronograph is used with a narrow-band polarizing filter or with a
- corposant = corona
- Consisting of particles,
specifically atomic particles.
- corpuscular cosmic rays
cosmic rays from outer space which consist mainly of protons with energies
of 2-20 billion electron volts (Bev).
- For 1000 protons there are about 80 helium nuclei, about 3 nuclei in
the carbon-nitrogen-oxygen range, and 1 or 2 heavier nuclei. The proton energy
may be as high as 105 Bev, and the other nuclei show an energy
distribution similar to that of the protons.
- corpuscular theory of light
- The hypothesis, by Sir Isaac Newton, that light consists of a stream of
minute particles emitted by luminous bodies at very high velocities, and that
the sensation of light, is due to the bombardment of the retina of the eye by
- Although this theory was later replaced by the wave
theory of light, the concept of photons in the modern quantum theory is
reminiscent of Newton theory.
- A quantity, equal in absolute magnitude to the error, added to a
calculated or observed value to obtain the true value.
- 1. In statistics, a relationship between two occurrences which is
expressed as number between minus one (-1) and plus one (+1).
- 2. When used without further qualification, the statistical term
correlation usually refers to simple, linear correlation between two
variables x and y and is measured by the product-moment
coefficient of correlation or its sample
estimate r defined as follows, where the respective population mean
values of x and y are denoted by
and , the respective standard deviations by ( x ) and (
y ), and where E is the expected value:
product-moment E[(x - )(y - )] is usually called the covariance of x and
y. See autocorrelation,
- In connection with correlation, the word simple is used in
contradistinction to other qualifiers such as multiple or
partial. The word linear refers to a linear relationship between
the two variables, or more precisely, to a linear approximation of the regression
function of either variable with respect to the other.
- correlation coefficient
- 1. See correlation,
- 2. A measure of the persistence of eddy
velocity as a function of time and space.
- correlation detection
- A method of detection in
which a signal is
compared, point-to-point, with an internally generated reference. Also called
cross correlation detection.
- The output of such a detector is a measure of the degree of similarity
of the input and reference signals. The reference signal is constructed in
such a way that it is at all times a prediction, or best guess, of what the
input signal should be at that time.
- correlation tracking and ranging (abbr Cotar)
- A nonambiguous trajectory-measuring system using short-baseline,
single-station, continuous-wave phase-comparison measuring two direction
cosines and a slant
- correlation tracking and triangulation (abbr Cotat)
- A trajectory
measuring system composed of several antenna baselines, each separated by
large distances, used to measure direction
cosines to an object.
- From these measurements its space position is computed by
- correlation tracking system
- A trajectory
measuring system utilizing correlation techniques where signals derived
from the same source are correlated to derive the phase difference
between the signals. This phase difference contains the system data.
- The deterioration of a metal by chemical or electrochemical reaction with
- International Astronomical Union abbreviation for Corvus. See constellation.
- Corvus (abbr Crv, Corv)
- See constellation.
- cosine law of illumination
- A purely geometric relationship between the illuminance
of a surface and the angle of incidence of the illuminating rays.
Mathematically, the illuminance I of the surface illuminated by a beam
of flux density F incident at angle is
I = F cos
- The marked latitudinal variation in insolation
on the earth is largely a consequence of this simple relationship. Compare Lambert
- Of or pertaining to the universe, especially that part of it outside the
earth's atmosphere. Used by the USSR as equivalent to space, as in cosmic
rocket, cosmic ship.
- cosmic dust
- Finely divided solid matter with particle sizes smaller than a micrometeorite,
thus with diameters much smaller than a millimeter, moving in interplanetary
space. See dust.
- Cosmic dust in the solar system is thought to be concentrated in the
plane of the ecliptic, thus causing the zodiacal
- cosmic noise
- Interference caused by cosmic
- cosmic radiation = cosmic
- cosmic radio waves
- Radio waves emanating
from extraterrestrial sources.
- They are galactic radio waves if their origin is within our
galaxy and extragalactic radio waves if their origin is outside our
galaxy. Solar radio waves emanate from the sun.
- cosmic-ray burst
- An extensive production of ionization from a common origin by cosmic rays
in a recording device such as a cloud
- cosmic-ray knee
- The point of sudden drop-off in the intensity of recorded cosmic rays
at about 40 degrees geomagnetic
- The drop-off is due to the shield effect of the earth's magnetic
- cosmic rays
- The aggregate of extremely high energy subatomic particles
which travel the solar system and bombard the earth from all directions.
Cosmic-ray primaries seem to be mostly protons, hydrogen nuclei, but also
contain heavier nuclei. On colliding with atmospheric particles they produce
many different kinds of lower energy secondary
cosmic radiation (see cascade
shower). Also called cosmic radiation.
- Cosmic rays thought to originate outside the solar system are
called galactic cosmic rays. Those thought to originate in the sun are
called solar cosmic rays.
In the earth's atmosphere, the maximum
flux of cosmic rays, both primary and secondary, is at an altitude of 20 km,
and below this the absorption of the atmosphere reduces the flux, though the
rays are still readily detectable at sea level. Intensity of cosmic-ray
showers has also been observed to vary with latitude, being more intense at
the poles. See cosmic-ray
- A Soviet astronaut, sense 1.
- COSPAR (abbr) = Committee on Space
Research, International Council of Scientific Unions.
- coulomb (abbr C)
- The unit of quantity of electricity; the quantity of electricity
transported in 1 second by a current of 1 ampere. Expression in terms of SI
base units: s * A.
See the WWW version of the National Institute of
Standards and Technology: Physics Laboratory's International System of Units
- Cotar (abbr) = correlation
tracking and ranging.
- Cotat (abbr) = correlation
tracking and triangulation.
- Couette flow
- The shearing flow of a fluid between two parallel surfaces in relative
motion. A two-dimensional steady flow without pressure gradient in the
direction of flow and caused by the tangential movement of the bounding
surfaces. The only practical type is the flow between concentric rotating
cylinders (as of the oil in a cylindrical bearing).
- Coulomb collision
- The collision of two particles
both of which are charged.
- In this case the collision
cross section is considerably larger than when one of the particles is
neutral because the electric field of the two particles can interact at much
larger distances. Since the collisions are distant ones, however, the
particles will suffer only a small angular deviation.
- Coulomb damping
- The dissipation of energy that occurs when a particle in a vibrating
system is resisted by a force whose magnitude is a constant independent of
displacement and velocity, and whose direction is opposite to the direction of
the velocity of the particle. Also called dry
- 1. To proceed from one point to another in a countdown or plus count,
normally by calling a number to signify the point reached; to proceed in a
countdown, as in T minus 90 and counting. Compare hold.
- 2. In radiation counters, a single response of the counting system.
- 1. A step-by-step process that culminates in a climactic event, each step
being performed in accordance with a schedule marked by a count in inverse
numerical order; specifically, this process is used in leading up to the
launch of a large or complicated rocket vehicle, or in leading up to a captive
test, a readiness firing, a mock firing, or other firing test.
- 2. The act of counting inversely during this process.
- In sense 2, the countdown ends with T-time; thus, T minus 60 minutes
indicates there are 60 minutes to go, excepting for holds and recycling. The
countdown may by hours, minutes, or seconds. At the end, it narrows down to
seconds, 4-3-2-1-0. See plus
- A device capable of changing from one to the next of a sequence of
distinguishable states upon each receipt of an input
signal. Also called accumulator.
- counterclockwise polarized wave = left-handed
- counterglow = gegenschein.
- A pressure applied to the exterior of the human body to counteract a
pressure introduced inside during pressure
- The downward flux of atmospheric
radiation passing through a given level surface, usually taken as the
earth's surface. Also called back radiation.
- This result of infrared (long-wave) absorption and reemission by the
atmosphere is the principal factor in the greenhouse
- countervane = contravane.
- coupled modes
- Modes of vibration
that are not independent but which influence one another because of energy
transfer from one mode to the other.
- 1. A device or contrivance for joining adjacent ends or parts of anything.
- 2. A device permitting transfer of energy from one
electrical circuit to another, or from one mechanical device to another.
- 1. A predetermined or intended route or direction to be followed, measured
with respect to a geographic reference direction; a line on a chart
representing a course.
- 2. A line of flight taken by an aircraft, rocket, etc.
- 3. A radio beam
in a radio range.
- course line
- 1. A line of
position plotted on a chart, parallel or substantially parallel to the
intended course of a craft, showing whether the craft is to the right or the
left of its course.
- 2. Any line representing a course.
- Cowell method
- A method of orbit computation
using direct step-by-step integration in rectangular coordinates of the total
acceleration of the orbiting body.
- The Cowell method is a special
- CrA, Cor A
- International Astronomical Union abbreviations for Corona
Australis. See constellation.
- Presence of relatively large cracks extending into the interior of a
structure, usually produced by overstressing the structural material. Compare
- 1. An aircraft, or aircraft collectively.
- 2. Any vehicle or machine designed to fly through air or space.
- International Astronomical Union abbreviation for Crater. See constellation.
- Crater (abbr Crt, Crat)
- See constellation.
- 1. = lunar
- 2. The depression resulting from high speed solid particle impacts on a
rigid material as a meteoroid
impact on the skin of a spacecraft.
- See lunar
- CrB, Cor B
- International Astronomical Union abbreviations for Corona Borealis.
- The slow but continuous deformation of a material under constant load or
prolonged stress (usually
critically encountered at elevated temperatures).
- creep strength
- The constant nominal stress that will
cause a specified quantity of creep in a given
time at constant temperature.
- See phases
of the moon.
- crippled leapfrog test
- In computer operations, a modified leapfrog
test in which tests are repeated from a single set of storage
locations and do not leap to another set of storage locations.
- In reactor theory, capable of sustaining a chain
reaction. See critical
- critical damping
- The minimum damping that
will allow a displaced system to return to its initial position without oscillation.
- critical frequency
- The limiting frequency
below which a magnetoionic
wave component is reflected by, and above which it penetrates through, an
ionized medium (plasma) at
- criticality factor
- As applied to a reactor, the numerical value of the effective
multiplication factor (ke), denoting the degree to which
has achieved a self-sustaining chain
- critical level = critical
level of escape.
- critical level of escape
- That level, in the atmosphere, at which a particle moving rapidly upwards
will have a probability of 1/e, where e is base of natural
logarithm, of colliding with another particle on its way out of the
atmosphere. It is also the level at which the horizontal mean free
path of atmospheric particle equals the scale
height of the atmosphere. The critical level of escape is the base of the
Also called level of escape, critical level. See cone of
- Estimates of the height of the critical level of escape range from
about 500 to 1000 kilometers. This large range of estimated values is due
primarily to the general uncertainty about the temperature distribution in the
- critical Mach number
- The free-stream
Mach number at which a local Mach number
of 1.0 is attained at any point on the body under consideration.
- For example, an airplane traveling at a Mach number of 0.8 with respect
to the undisturbed flow might attain Mach number of 1 in the flow about the
wing; the critical Mach number would thus be 0.8.
- critical mass
- The amount of concentrated fissionable
material that can just support a self-sustaining fission
- critical point
- The thermodynamic
state in which liquid and gas phases of a
substance coexist in equilibrium at the highest possible temperature. At
higher temperatures than the critical no liquid phase can exist. For water
substance the critical point is
Ps = 2.21 X 10 5 millibars
T = 647°
v = 3.10 grams/cubic centimeter
where Ps is the saturation vapor pressure of the water
vapor; T is the Kelvin temperature; and v is the specific
- critical pressure
- 1. In rocketry, the pressure in the nozzle
throat for which the isentropic weight
flow rate is a maximum.
- 2. The pressure of a gas at critical
point, which is the highest pressure under which a liquid can exist in
equilibrium with its vapor.
- critical reactor
- The steady-state condition of a reactor in
which the neutron fission process
is self-sustaining without the aid of external neutron sources. A critical
reactor has a criticality
factor of one (ke = 1).
- critical Reynolds number
- The Reynolds
number at which some significant change occurs, e.g., the Reynolds number
at which a transition from laminar to
flow begins, or at which the drag of a cylinder
or sphere drops sharply.
- critical speed
- A speed of a rotating system that corresponds to a resonance
frequency of the system.
- critical temperature
- 1. The temperature
above which a substance cannot exist in the liquid state,
regardless of the pressure.
- 2. As applied to reactor overheat or afterheat,
the temperature at which the least resistant component of the reactor
core begins to melt down.
- 3. As applied to materials, the temperature at which a change in phase
takes place causing an appreciable change in the properties of the material.
- critical throat velocity = critical
- critical velocity
- In rocketry, the speed of
sound at the conditions prevailing at the nozzle
throat. Also called throat velocity, critical throat velocity.
- cross correlation detection = correlation
- A flow
going across another flow, as a spanwise flow over a wing.
- crossflow plane
- In aerodynamics, a plane at right angles to the free-stream
velocity. Compare crossflow.
- A hair, thread, or wire constituting part of a reticle.
- cross modulation
- In general, modulation
of a desired signal by an
- See supercommutation.
- cross product = vector
- cross section
- 1. A measure of the effectiveness of a particular process expressed either
as an area (geometric cross section) which would produce the observed result,
or as a ratio. See absorption
cross section, scattering
- 2. = nuclear
- cross sensitivity
- The ratio of change in output to an incremental change in a given stimulus
along any axis perpendicular to the sensitive axis.
- In accelerometers it refers to the change in the transducer output at
zero acceleration and at some other acceleration value applied along a plane
perpendicular to the sensitive axis.
- Electrical disturbances in a communication channel as a result of coupling with
other communication channels.
- That wind vector component which is perpendicular to the course of an
exposed moving object. Compare range wind.
- Crt, Crat
- International Astronomical Union abbreviations for Crater. See constellation.
- International Astronomical Union abbreviations for Crux. See constellation.
- Crux (abbr Cru, Cruc)
- See constellation.
- CRT (abbr)
- Crv, Corv
- International Astronomical Union abbreviations for Corvus. See constellation
- cryogenic materials
- Those metals and alloys which are usable in structures operating at very
low temperature, and usually possess improved strength properties at these
- cryogenic propellant
- A rocket fuel, oxidizer, or
propulsion fluid which is liquid only at very low temperatures.
- cryogenic pump
- A type of pump which uses cryopumping
to attain a vacuum.
- 1. The study of the methods of producing very low temperatures.
- 2. The study of the behavior of materials and processes at cryogenic
- cryogenic temperature
- In general, a temperature range below the boiling point of nitrogen (-195°
C); more particularly, temperatures within a few degrees of absolute zero.
- 1. An exposed surface refrigerated to cryogenic
temperature for the purpose of pumping gases in a vacuum chamber by
condensing the gas and maintaining the condensate at a temperature such that
the equilibrium vapor pressure is equal to or less than the desired ultimate
pressure in the chamber.
- 2. The act of removing gases from an enclosure by condensing the gases on
surfaces at cryogenic temperature.
- Also referred to as a cryogenic pump and not to be confused with
cryogenic fluid pump for circulating cryogenic propellants.
- The process of removing gas from a system by condensing it on a surface
maintained at very low temperatures.
- A device based upon the principle that superconductivity
established at temperatures near absolute zero is destroyed by the application
of a magnetic field.
- crystal lattice
- The three-dimensional, recurring pattern in which the atoms of a crystal
- crystal transducer
- A transducer
in which the method of transduction is accomplished by means of the piezoelectric
properties of certain crystals or salts. Also called crystal.
- C-scan = C-display.
- C-scope = C-display.
- culmination = transit (sense
1), specifically upper
- curie (abbr C)
- The unit of the rate of radioactive
decay; the quantity of any radioactive nuclide which
undergoes 3.70 X 1010 disintegrations per second.
- Curie point
- The temperature in a ferromagnetic
material above which the material becomes substantially nonmagnetic.
- Curie temperature = Curie
- A vector
operation upon a vector field which represents the rotation of the field,
related to the circulation of the field at each point. The curl is invariant
with respect to coordinate transformations and is usually written "curl F" of
" * F" where is the
del-operator. In Cartesian coordinates, if F has the components Fx,
Fy, Fz the curl is
in other coordinate systems may be found in any text on vector analysis.
- The curl of a two-dimensional vector field is always in a field of
solid rotation it is equal to twice the angular velocity. Occasionally the
vorticity is defined as one-half the curl.
The curl of a two dimensional
vector field is always normal to the vectors of the field; this is not
necessarily true in three dimensions. Compare divergence.
- A device used with an instrument to provide a movable reference, as the
runner of a slide rule or a ratable plastic disk with inscribed crosslines,
used in reading bearings on a plan
- Curtis turbine
- A turbine in
which a stationary set of blades is used to change the direction of the fluid
flow as the fluid travels between two sets of rotating blades.
- curved-path error
- The difference between the length of a ray refracted by
and the straight-line distance between the ends of the ray.
- curve of growth
- In spectroscopy, the relationship between the amount of radiant
energy removed by an absorption
line and the number of atoms or molecules of the absorbing gas in the
- If the logarithm of energy absorbed is plotted against the logarithm of
amount of gas in the path, the resulting curve of growth usually has two
straight-line segments. The first, for small absorption and small amounts of
gas, has a slope of 1; the second, for large absorption and large amounts of
gas, has a slope of 1/2. Thus, initially absorption is directly proportional
to the number of atoms or molecules, but as the line becomes more intense,
absorption becomes proportional to the square root of the number of atoms or
molecules. Between these two straight-line segments there is often a portion
in which an increase in the amount of gas in the path produces very little
increase in total absorption. All of this discussion applies in the case of
gaseous emission as
well as absorption.
- curve of regression
- A realistic curve having a least-squares
fit to the data points.
- There are an infinity of least-squares curves to fit a set of data
points (one curve of which touches every point). Therefore, the regression
curve must be the best least-squares estimate (of the true curve of the
phenomenon observed) that can be made in light of the data and prior knowledge
of the physics of the phenomenon observed. Note that a regression curve is
offset from the true curve by the amount of any bias error and of most
- curvilinear coordinates
- Any linear coordinates
which are not Cartesian
coordinates. Examples of frequently used curvilinear coordinates are polar
coordinates and cylindrical
coordinates. See natural
- cutoff or cut-off
- 1. An act or instance of shutting something off; specifically, in
rocketry, an act or instance of shutting off the propellant
flow in a rocket, or of stopping the combustion
of the propellant. Compare burnout.
- 2. Something that shuts off, or is used to shut off. See fuel
- 3. Limiting or bounding as in cutoff frequency.
- Cvn, C Ven
- International Astronomical Union abbreviations for Canes Venatici.
- CW radar = continuous-wave
- CW system
- A trajectory
measuring system that utilizes a continuous-wave
signal to obtain information on the trajectory of a target.
- An instrument designed to measure or estimate the blueness of the sky.
- The type in most common use is the Linke
- The study and measurement of the blueness of the sky.
- The characteristic blue color of clear skies is due to preferential scattering
of the short wavelength components of visible sunlight by air molecules.
Presence of foreign particles in the atmosphere alters the scattering
processes in such a way as to reduce the blueness. Hence spectral analysis of
sky radiation provides useful information concerning the scattering
- The study of methods of control and
communication which are common to living organisms and machines.
- cycle (symbol c)
- 1. The complete sequence of values of a periodic
quantity that occur during a period.
- 2. One complete wave, a frequency of
1 wave per
- 3. Any repetitive series of operations or events.
- cycle efficiency
- The efficiency of a given cycle in an
internal combustion engine, in producing work, expressed as the useful work
output divided by the work input. For a gas-turbine engine, the cycle
efficiency is the useful work energy less the work required for compression
divided by the heat energy in the fuel used; for a reciprocating engine, it is
the energy of the indicated horsepower divided by the heat energy of the fuel.
- Of or pertaining to a cycle or cycles.
- cyclic code
- In computer operations, a positional
notation, not necessarily binary, in which quantities differing by one
unit are represented by expressions which are identical except for one place
or column, and the digits in that place or column differ by only one unit.
Also called reflected
code. See Gray code.
- Having a sense of rotation about
vertical the same as that of the earth's rotation: that is, as viewed from
above, counterclockwise in the Northern Hemisphere, clockwise in the Southern
Hemisphere, undefined at the equator; the opposite of anticyclonic.
- A name given to a generic type of vacuum tube
utilizing a beam of electrons as a switching or commutating element.
- A device for accelerating charged particles to
high energies by giving particles traveling in a spiral path successive
increments of energy from an alternating electric field between electrodes
placed in a constant magnetic field. The path radius increases as energy
- cyclotron frequency
- The frequency at
which a charged particle
orbits in a uniform magnetic field. It depends on the charge to mass ratio of
the particle times the magnetic field. While the frequency is independent of
the particle energy, the Larmor
orbit increases with energy. Sometimes called the Larmor frequency.
- In a magnetic field of 1 gauss, the electron cyclotron frequency is 2.8
megacycles per second and the proton cyclotron frequency is 1.5 kilocycles per
- cyclotron radiation
- The electromagnetic
radiation emitted by charged particles as
they orbit in a magnetic field. The radiation arises from the centripetal
acceleration of the particle as it moves in a circular orbit. See Larmor
- When the velocity is small, the radiation is concentrated in a single
spectral line, at the cyclotron
frequency. The spectral line is spread into a band of frequencies,
however, from the effects of Doppler, Stark, and collision broadening. In
addition, as the speed of the particles approaches the velocity of light,
higher harmonics of the cyclotron radiation occur at multiples of the
- cyclotron resonance
- Energy transfer to charged particles in
a magnetic field from an alternating-current electric field whose frequency is
equal to the cyclotron
- An analogous physical situation is the large increase in the motion of
a pendulum if it is given a little push in every period of its natural
oscillation. Such a technique is useful in heating either the electrons or
- Cyg, Cygn
- International Astronomical Union abbreviations for Cygnus. See constellation.
- Cygnus (abbr Cyg, Cygn)
- See constellation.
- cylindrical coordinates
- A system of curvilinear
coordinates in which the position of a point in space is determined by (a)
its perpendicular distance from a given line, (b) its distance from a selected
reference plane perpendicular to this line, and (c) its angular distance from
a selected reference line when projected onto this plane. The coordinates thus
form the elements of a cylinder, and, in the usual notation, are written,
r, , and z where r is the
radial distance from the cylinder's axis z, and is the angular position from a reference line in a
cylindrical cross section normal to z. Also called cylindrical polar
coordinates, circular cylindrical coordinates. See polar
- The relations between the cylindrical coordinates and the rectangular
Cartesian coordinates (x, y, z) are x = r
cos , y = r sin , z = z.
- cylindrical polar coordinates = cylindrical
- cylindrical wave
- A wave in
which the wave fronts are coaxial cylinders.