Anti-Satellite Weapons, Countermeasures, and Arms Control

154 Pages·1995·2.88 MB·English

Anti-Satellite Weapons, Countermeasures,
and Arms Control
September 1985
NTIS order #PB86-182953
Recommended Citation:
U.S. Congress, office of Technology Assessment, A nti-.%]h~llih’ W(wp(m.s, ( ‘(wnhv--
metisures, and Arms Cmh-of, (WA- 1.S(;-281 (Wash inglx)n, 1 W: (J .S. ( ;f)vt’r-ntm’nt
I)rinting office, Sepkmher 1 985).
I.ibrary of Congress Catalog Card Number 85-600587”
For sale by the Superintendent of l)ocumcnts
U.S. Government f’rinting office, Washington, 1)C 20402
Foreword
///
Advisory Panel on New Ballistic Missile Defense Technologies
l
Iv
OTA Project Staff on New Ballistic Missile Defense Technologies
Administrative Staff
Jannie Coles Dorothy Richroath Jackie Robinson
Glossary of Acronyms and Terms
Glossary of Acronyms
Glossary of Terms
they are deployed from a booster or post-boost Delta-V: A numerical index of the maneuverabil-
vehicle until they are destroyed. ity of a satellite or rocket, It is the maximum
Bistatic Radar: A radar system which has trans- change in velocity which a spacecraft could
mitters and receivers stationed at two locations; achieve in the absence of a gravitational fieId.
a special case of multistatic radar. Diffraction: The spreading out of electromagnetic
Boost Phase: The phase of a missile trajectory radiation as it leaves an aperture, such as a mir-
from launch to burnout of the final stage. For ror. The degree of spread, which cannot be elim-
ICBMS, this phase typically lasts from 3 to 5 inated by focusing, is proportional to the ratio
minutes, but studies indicate that reductions to of the wavelength of radiation to the diameter
the order of 1 minute are possible. of the aperture.
Brightness: In this report, the amount of power Digital Processing: The most familiar type of com-
that can be delivered per unit solid angle by a puting, in which problems are solved through
directed-energy weapon. the mathematical manipulation of streams of
Capital Satellite: A highly valued or costly satel- numbers.
lite, as distinct from an inexpensive decoy sat- Directed-Energy Weapon: A weapon that kills its
ellite. Some decoys might be so expensive as to target by delivering energy to it at or near the
be considered capital satellites. speed of light. Includes lasers and particle beam
Chaff: Confetti-like metal foil ribbons which can weapons.
be ejected from spacecraft (or terrestrial vehi- Discrimination: The ability of a surveillance sys-
cles) to reflect enemy radar signals, thereby cre- tem to distinguish decoys from intended tar-
ating false targets or screening actual targets gets, e.g., certain types of satellites.
from the “view” of radar. Early Warning: In this report, early detection of
Coherence: The matching, in space (transverse) or an enemy ballistic missile launch, usually by
time (temporal coherence), of the wave structure means of surveillance satellites and long-range
of different parallel rays of a single frequency radar.
of electromagnetic radiation. This results in the Electromagnetic Radiation: A form of propagated
mutual reinforcing of the energy of these differ- energy, arising from electric charges in motion,
ent components of a larger beam. Lasers and ra- that produces a simultaneous wavelike varia-
dar systems produce partially coherent ra- tion in electric and magnetic fields in space. The
diation. highest frequencies (or shortest wavelengths) of
Command Guidance: The steering and control of such radiation are possessed by gamma rays,
a missile by transmitting commands to it. which originate from processes within atomic
Counter-countermeasures: Measures taken to de- nuclei. As one goes to lower frequencies, the
feat countermeasures. electromagnetic spectrum includes X-rays, ul-
Countermeasures: In this report, measures taken traviolet light, visible light, infrared light,
by the offense to overcome aspects of a BMD microwave, and radio waves.
system. Electron-volt: The energy gained by an electron in
Dazzling: In this report, the temporary blinding passing through a potential difference of 1 volt.
of a sensor by overloading it with an intense sig- 6.25 quintillion electron-volts equals 1 joule;
nal of electromagnetic radiation, e.g., from a la- 22.5 billion trillion electron-volts equals 1 kilo-
ser or a nuclear explosion. watt-hour.
Decoy: An object that is designed to make an ob- Elliptical Orbit: A noncircular Keplerian orbit.
server believe that the object is more valuable Endoatmospheric: Within the atmosphere; an en-
than is actually the case. Usually, in this report, doatmospheric interceptor intercepts its target
a decoy refers to a Iight object designed to look within the atmosphere.
like a satellite. Ephemeris: A collection of data about the pre-
Deep Space: The region of outer space at altitudes dicted positions (or apparent positions) of celes-
greater than 3,000 nautical miles (about 5,600 tial objects, including artificial satellites, at va-
kilometers) above the Earth’s surface. rious times in the future. A satellite ephemeris
Defensive Satellite (DSAT) Weapon: A space- might contain the orbital elements of satellites
based ASAT weapon that is intended to defend and predicted changes in these.
satellites by destroying attacking ASAT Equatorial Orbit: An orbit above the Earth’s
weapons. Equator.
Defensive Technologies Study Team (DTST): A Excimer: A contraction for “excited dimer”; a type
committee, generally known as the “Fletcher of lasant. A dimer is a molecule consisting of
Panel, ” after its Chair, appointed by President two atoms. Some dimers—e.g., xenon chloride
Reagan to investigate the technologies of poten- and krypton fluoride-are molecules which can-
tial BMD systems. not exist under ordinary conditions of approxi-
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mate thermal equilibrium but must be created above the Equator. A satellite placed in such
in an “excited’ ’-i.e., energized-condition by an orbit revolves around the Earth once per day.
special “pumping” processes in a laser. See Geostationary Orbit.
Exoatmospheric: Outside the atmosphere; an exo- Gray: The Syst6me International unit of absorbed
atmospheric interceptor intercepts its target in dose of ionizing radiation. One gray (abbrevi-
space. ated 1 Gy) is 1 joule of absorbed energy per kilo-
Fission: The breaking apart of the nucleus of an gram of matter.
atom, usually by means of a neutron. For very Hard Kill: Destruction of a target in such a way
heavy elements, such as uranium, a significant as to produce unambiguous visible evidence of
amount of energy is produced by this process. its neutralization.
When controlled, this process yields energy Hardness: A property of a target; measured by the
which may be extracted for civilian uses, such power needed per unit area to destroy the tar-
as commercial electric generation. When uncon- get by means of a directed-energy weapon. A
trolled energy is liberated very rapidly: such fis- hard target is more difficult to kill than a soft
sion is the energy source of uranium- and plu- target,
tonium-based nuclear weapons; it also provides High-Earth Orbit: An orbit about the Earth at an
the trigger for fusion weapons. altitude greater than 3,000 nautical miles (about
Fratricide: In this report, the unintended destruc- 5,600 kilometers).
tion of some of a nation’s weapons or other mil- Homing Device: A device, mounted on a missile,
itary systems (e. g., satellites) by others. that uses sensors to detect the position or to
Free-electron Laser: A type of laser which does not help predict the future position of a target, and
use ordinary matter as a lasant but instead gen- then directs the missile to intercept the target.
erates radiation by the interaction of an electron It usually updates frequently during the flight
beam with a static magnetic or electric field. of the missile.
Loosely speaking, free-electron laser technology Impulse: A mechanical jolt delivered to an object.
resembles and evolved from that used by par- Physically, impulse is a force applied for a pe-
ticle accelerators (“atom smashers”). Lasers riod of time, and the Systi$me Internationale
which are not freeelectron lasers are bound- unit of impulse is the newton-second (abbre-
electron lasers. viated N-s). See Impulse Intensity.
Functional Kill: The destruction of a target by dis- Impulse Intensity: Mechanical impulse per unit
abling vital components in a way not immedi- area. The Systeme International unit of im-
ately detectable, but nevertheless able to pre- pulse intensity is the pascal-second (abbreviated
vent the target from functioning properly. An Pa-s) A conventionally used unit of impulse in-
example is the destruction of electronics in a tensity is the “tap,” which is one dyne-second
guidance system by a neutral particle beam. per square centimeter; hence 1 tap = 0.1 Pa-s.
Fusion: More specifically, nuclear fusion: The fus- Impulse Kill: The destruction of a target, using
ing of two atomic nuclei, usually of light ele- directed energy, by ablative shock. The inten-
ments, such as hydrogen. For light elements, sity of directed energy maybe so great that that
energy is liberated by this process. Hydrogen the surface of the target violently and rapidly
bombs produce most of their energy through boils off delivering a mechanical shock wave to
the fusion of hydrogen into helium. the rest of the target and causing structural
Graser: See Gamma-ray Laser. failure.
Gamma-ray Laser: A laser which generates a beam Inclination: The inclination of an orbit is the (di-
of gamma rays; also called a graser. A gamma- hedral) angle between the plane containing the
ray laser, if developed, would be a type of X-ray orbit and the plane containing the Earth’s
laser; although it would employ nuclear reac- Equator. An equatorial orbit has an inclination
tions, it need not (but might) employ nuclear fis- of 00 for a satellite traveling eastward or 1800
sion or fusion reactions or explosions. for a satellite traveling westward. An orbit hav-
Gamma Rays: X-rays emitted by the nuclei of ing an inclination between 00 and 900 and in
atoms. which a satellite is traveling generally eastward
Geostationary Orbit: An orbit at an altitude of is called a prograde orbit. An orbit having an
35,800 kilometers above the Earth’s Equator. inclination of 900 passes above the north and
A satellite placed in such an orbit revolves south poles and is called a polar orbit. An orbit
around the Earth once per day, maintaining the having an inclination of more than 900 is called
same position relative to the surface of the a retrograde orbit.
Earth. It then appears to be stationary, and can Ionization: The removal or addition of one or more
be used as a communications relay or as a sur- electrons to a neutral atom, forming a charged
veillance post. ion.
Geosynchronous Orbit: An orbit about 35,800 km Isotropic: Independent of direction; referring to
. . .
Vlll
the radiation of energy, it means “with equal crowaves. The light is bounced off a target and
intensity in all directions, ” i.e., omnidirectional. then detected, with the return beam providing
Isotropic Nuclear Weapon (INW): A nuclear explo- information on the distance and velocity of the
sive which radiates X-rays and other forms of target.
radiation with approximately equal intensity in Limited Test Ban Treaty: The multilateral Treaty
all directions. The term “isotropic” is used to signed and ratified by the United States and the
distinguish them from nuclear directed-energy U.S.S.R. in 1963 which prohibits nuclear tests
weapons. in all locations except underground.
Joule: The Systeme International unit of energy. Megawatt: One million watts; a unit of power. A
One kilowatt-hour is 3.6 million joules. typical commercial electric plant generates
Keep-out Zone: A volume around a space asset, off about 500 to 1,000 megawatts.
limits to parties not owners of the asset. Keep- MeV: One million electron-volts. A unit of energy
out zones could be negotiated or unilaterally usually used in reference to nuclear processes.
declared. The right to defend such a zone by It is equivalent to the energy that & electron
force and the legality of unilaterally declared gains in crossing a potential of 1 million volts.
zones under the Outer Space Treaty remain to Micron: One-millionth of a meter (equivalently,
be determined. one-thousandth of a millimeter). Roughly twice
Kelvin Temperature: A scale of temperature on the wavelength of visible light.
which zero degrees Kelvin (abbreviated 00 K) Midcourse Phase: The phase of a ballistic missile
corresponds to “absolute zero. Temperature in trajectory in which the RVS travel through
degrees Kelvin equals temperature in degrees space on a ballistic course towards their targets.
Celsius plus 273.16, thus ice melts at 273.16 G This phase lasts up to 20 minutes.
K, and water boils at 373.16° K. Military Satellite (MILSAT): A satellite used for
Keplerian Orbit: The orbit which a satellite would military purposes, such as navigation or intel-
follow if the Earth were a uniform sphere with ligence gathering.
no atmosphere, and if other simplifying assump- Miniature Homing Vehicle (MHV)/Miniature Vehicle
tions were valid. Such an orbit would be an el- (MV): An air-launched direct-ascent (“pop-up”)
lipse having the center of the Earth as one fo- kinetic-energy ASAT weapon currently being
cus. A special case of such an orbit is a circular developed and tested by the U.S. Air Force.
orbit about the center of the Earth. Monostatic Radar: A radar system in which the
Kill Assessment: The detection and assimilation receiver and transmitter are colocated.
of information indicating the destruction of an Multistatic Radar: A radar system that has trans-
object under attack. Kill assessment is one of mitters and receivers stationed at multiple loca-
the many functions to be performed by a bat- tions; typically, a radar system with a transmitter
tle management system. and several receivers, all of which are geo-
Kinetic-Energy Weapon: A weapon that uses ki- graphically separated. A special case is bistatic
netic energy, or energy of motion, to kill an ob- radar. An advantage of multistatic radar over
ject. Weapons that use kinetic energy are a monostatic radar is that even if transmitters—
rock, a bullet, a nonexplosively armed rocket, which might be detected by the enemy when
and an electromagnetic radgun. operating-are attacked, receivers in other loca-
Lasant: A material that can be stimulated to pro- tions might not be noticed and might thereby
duce laser light. Many materials can be used as escape attack.
lasants; these can be in solid, liquid, or gaseous Obscur-&.nt: A material-e. g., smoke or chaff-used
form (consisting of molecules–including exci- to conceal an object from observation by a ra-
mers— or atoms) or in the form of a plasma (con- dio or optical sensor. Smoke maybe used to con-
sisting of ions and electrons). Lasant materials ceal an object from observation by an optical
useful in high-energy lasers include carbon di- sensor, and chaff may be used to conceal an ob-
oxide, carbon monoxide, deuterium fluoride, ject from observation by a radio sensor (e.g.,
hydrogen fluoride, iodine, xenon chloride, kryp- radar).
ton fluoride, and selenium, to mention but a few. On-line: Operating, as distinct from dormant.
Laser: A device that produces a narrow beam of Orbital Elements: Any set of several parameters
coherent radiation through a physical process (e.g., apogee, perigee, inclination, etc.) used to
known as stimulated emission. Lasers are able specify a Keplerian orbit and the position of a
to focus large quantities of energy at great dis- satellite in such an orbit at a particular time.
tances, and are among the leading candidates Seven independent orbital elemets are required
for BMD weapons. to umambiuously specify the position of a sat-
LIDAR: A technique analogous to radar, but ellite in a Keplerian orbit at a particular time.
which uses laser light rather than radio or mi- Outer Space Treaty of 1967: A multilateral treaty
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signed and ratified by both the United States formation can be used for tracking, aiming, dis-
and the Soviet Union. Article IV of the Outer crimination, attacking, kill assessment, or all of
Space treaty forbids basing nuclear weapons or the above. Sensors may detect any type of elec-
other weapons of mass destruction in space. tromagnetic radiation or several types of nu-
Passive Sensor: One that detects naturally occur- clear particles.
ring emissions from a target for tracking and/or Shoot-back In this report, the technique of defend-
identification purposes. ing a space asset by shooting at an attacker.
Perigee: The minimum altitude attained by an Signature: Distinctive type of radiation emitted
Earth satellite. or reflected by a target, which can be used to
Phased-Array Radar (PAR): A radar with elements identify that target.
that are physically stationary, but with a beam Simulation: The art of making a decoy look like
that is electronically steerable and can switch a more valuable strategic target See Anti-simu-
rapidly from one target to another. Used for lation.
tracking many objects, often at great distances. Slew Time: The time needed for a weapon to reaim
Pointing: The aiming of sensors or defense weap- at a new target after having just fired at a pre-
ons at a target with sufficient accuracy either vious one.
to track the target or to aim with sufficient ac- Smoke: An obscurant which may be used in the
curacy to destroy it. atmosphere or in space to conceal an object
Polar Orbit: An orbit having an inclination of900. from observation by an optical sensor.
Prograde Orbit: An orbit having an inclination of Soft Kill: Same as functional kill.
between 0° and 90°. See Retrograde Orbit. Space Detection And Tracking System (SPADATS):
Pumping: In this report, the raising of the mole- A network of space surveillance sensors oper-
cules or atoms of a lasant to an energy state ated by the U.S. Air Force.
above the normal lowest state, in order to pro- Space Mines: Hypothetical devices that can track
duce laser light. This results when they fall back and follow a target in orbit, with the capability
to a lower state. Pumping may be done using of exploding on command or by pre-program,
electrical, chemical, or nuclear energy. in order to destroy the target.
Rad: A unit of absorbed dose of ionizing radiation. Stimulated Emission: Physical process by which
One rad is 0.001 gray. an excited molecule is induced by incident ra-
Radar: A technique for detecting targets in the diation to emit radiation at an identical fre-
atmosphere or in space by transmitting radio quency and in phase with the incident radiation.
waves (e.g., microwaves) and sensing the waves Lasers operate by stimulated emission.
reflected by objects. The reflected waves (called Superfluorescence: See Superradiance.
“returns” or “echos”) provide information on Superradiance: The process used by a superradiant
the distance to the target and the velocity of laser to generate or amplify a laser beam in a
the target and may also provide information single pass through a lasant material, or—in the
about the shape of the target. (Originally an case of a free-electron laser—through an electric
acronym for “RAdio Detection And Ranging.”) or magnetic field in the presence of an electron
Radian: A unit of angular measure. One radian is beam. Superradiance is actually a form of stim-
about 57.30. One microradian (0.000001 radian) ulated emission. Also known as superfluores-
is the angle subtended by an object 1 meter cence, or amplified spontaneous emission.
across at a distance of 1,000 kilometers. Superradiant Laser: A laser in which the beam
Reaction Decoy: A decoy deployed only upon passes through the lasant only once; mirrors are
warning or suspicion of imminent attack. not required for the operation of such a laser,
Reentry: The return of objects, originally launched as they are with more conventional lasers which
from Earth, into the atmosphere. are sometimes called “cavity lasers” to distin-
Retrograde Orbit: An orbit having an inclination guish them from superradiant lasers. Free-elec-
of more than 900. See Prograde Orbit. tron lasers may also be superradiant; the laser
Robust: In this report, describing a system, in- beam of a superradiant free-electron laser would
dicating its ability to endure and perform its pass once through an electric or magnetic field
mission against a reactive adversary. Also used (instead of a lasant) in the presence of an elec-
to indicate ability to survive under direct tron beam.
attack. Synthetic Aperture Radar (SAR): A radar system
Salvage-fused: Describing a warhead, that is set which correlates the echoes of signals emitted
to detonate when it is attacked. Usually refers at different points along a satellite’s orbit or an
to a nuclear warhead. airplane’s flight path. The highest resolution
Sensors: Electronic instruments that can detect ra- achievable by such a system is theoretically
diation from objects at great distances. The in- equivalent to that of a single large antenna as
x