ANTI-SATELLITE WEAPONS (ASATS)
The following is a brief introduction for the non-space weapons expert by a
layperson gleaned primarily from university-level library and Internet
resources and will provide a brief history of negotiated treaties, describe
the early U.S. and Russian ASAT systems, describe the ‘current’ ASAT systems
being developed, and describe some of the future ASAT systems planners
envision. Some novel ASAT systems will be described. Hardening techniques
will be briefly described and finally, implications on future problems
relating to the health of humans living in our atmosphere will be suggested.
ASATs or anti-satellite weapons are any object or process with the potential
to destroy or make inoperable a satellite.
The following brief legal history is important given that international
treaties will be either renegotiated, broken, or continually broken as
presently researched systems and future systems are tested and deployed.
The Partial Test-Ban Treaty, signed on August 5, 1963 bans nuclear weapons
testing in the atmosphere, in outer space, and under water. The next
international treaty, the Outer Space Treaty, was signed on January 27, 1967
and says this: "States parties to the Treaty undertake not to place in orbit
around the Earth any objects carrying nuclear weapons or any other kinds of
weapons of mass destruction, install such weapons on celestial bodies, or
station such weapons in outer space in any other manner..." (7).
The ABM (Anti- Ballistic Missile) Treaty
was signed May 26, 1972 and states: "Each Party undertakes to not develop, test, or deploy ABM systems or components
which are sea-based, air-based, space-based, or mobile land-based" (7). The
ABM treaty does not specifically prohibit research on and development of
anti-satellite weapons, thus, this provides loopholes. ASATs and ABM weapons
use the same technologies so that ABM weapons can be developed by developing
ASATs, ..... treaties can be broken, disregarded, or euphemistically
sidestepped. As an example of how our government will skirt the law,
although treaties disallow testing of anti-satellite weapons against
satellites in space, the U.S. recently tested a laser against an Air Force
satellite in space. The government claimed it was not testing the laser as a
weapon but, rather, was testing the ‘survivability’ of the satellite.
Semantic quibbling to get around the law!
The U.S. and Russians have been developing ASATs since the late 50's. The
first successful satellite intercept occurred May 24, 1962 and was launched
by the U.S. from Kwajalein Atoll. It was reported as a "close intercept ".
The first generation ASATs were either non-nuclear or nuclear ballistic
missile launched weapons that were either direct hit-to-kill devices, or
satellites that in close proximity to the target satellite would explode with
the satellite debris as the shrapnel particles that destroy the target
satellite. In the case of nuclear-tipped rocket used as an ASAT, the thermal
blast, x-rays, or other radiation effects, or electro-magnetic effects would
be the kill mechanism. An early Russian ASAT effort was a multi-staged
rocket with a small ground controlled satellite with direct hit-to-kill
capability. A self-guided homing vehicle was tried using infrared homing,
but the system failed several times in testing, was not successful in the
60's, and was dropped.
The American developed and tested exoatmospheric (outside Earth’s atmosphere)
nuclear ASATs using kiloton, and, a 1.4 megaton nuclear weapon was detonated
at an altitude of 248 miles on July 9, 1962. The actual satellite kill
mechanism for nuclear explosion results from thermal heating, through
magnetic field effects on electronic components and semi-conductors. X-ray
radiation hitting the satellite surface creates a very high surface
electrical potential and high surface currents. These surface currents
produce strong magnetic fields that penetrate the satellite metal skin and
disrupt satellite electronics. At the time of these tests, designers were
‘plagued’ with a highly disruptive "electromagnetic pulse" that could and did
destroy satellites that were unintended as targets. The Americans abandoned
nuclear testing in space, but the "system generated electro-magnetic pulse"
was seen as a potential energy source for latter generation ASAT designs.
They are still on the weapons designer’s tables.
In the 1970s, the Americans pursued a two-tracked strategy of attempting to
negotiate with the Soviets to eliminate ASAT systems of the future and
simultaneously developing a new ASAT system, an air-launched missile with
infrared homing capability. A two-staged rocket was launched from a Navy
F-15 jet at high altitude. The rocket was tipped with a miniature homing
vehicle, self-propelled with on-board guidance that was a direct hit-to-kill
system. The homing system used infrared radiation (heat) to guide the kill
vehicle to crash into the target satellite. That system was defunded in
segments, from 100 or so launch vehicles at the start, 40+ F-15s, and then
down to where it was eventually dropped during the Reagan administration.
It was never operational as a system although tests confirmed that it could
knock a satellite out of the sky.
A radical shift in interest in ASATs, funding for ASATs, and development of
ASATs took place in the Reagan presidency and continues to today. In 1965,
Arthur Kantrowitz, the then-Director of AVCO Corporation, probably made the
"first proposal for the use of particle beam weapons..." (6). In addition to
the particle beams, the newer generation of ASATs includes another category
of weapons referred to as ‘Directed Energy Weapons (DEWs). The distinction
between the two is sometimes blurred. Particle beam weapons are a group of
weapons that use electro-magnetic energy to accelerate particles, neutral
atoms being likely candidates, to velocities close to the speed of light. A
particle beam weapon called a ‘rail gun,’ is said to accelerate ‘charged’
particles to very high velocities. High-energy particle beams would, like
nuclear explosions, either produce high surface temperatures, burning out the
satellite electronics, produce high surface currents that would in turn
produce electro-magnetic fields that would penetrate the skin of the
satellite and disrupt sensitive electronics, or produce ions, electrically
charged particles, that, depending on the particle type and energy, would
disrupt satellite electronics by way of various radiation effects.
Lasers are part of a group of the DEWs that are, in fact, being built and
tested. There are several types of lasers that can be used for ASAT weapons
but all are devices that deliver highly focused energy as the "thing" that
destroys. A wide spectrum of energy sources is available for use as the
"stuff" that is moved, at the speed of light, carrying the destructive force.
X-rays are the sources of an ‘eximer’ laser, where light is the source for
LASER ASATs, and microwaves are the source for MASER ASATs. LASER is an
acronym for the phrase-Light Amplification by Stimulated Emission of
Radiation. MASER =Microwave Amplification by Stimulated Emission of
Radiation. Directed energy weapons therefore will be streams of elementary
particles, atoms, electrons, ions, light, microwaves, x-rays, gamma rays and
even high powered plasmas that are accelerated to very high velocities that
can ruin or destroy satellites.
There is a separate class of DEWS that, as a group, are planned to be spaced
based; that is, as satellites themselves. They are called "nuclear pumped
ASATs". These are weapons that will use a nuclear detonation in space which
will produce x-rays, neutrons, gamma rays, or other parts of the
electro-magnetic spectrum that will then be directed at the target satellite.
These weapons will instantaneously destroy themselves in the nuclear
detonation, are therefore one shot weapons that present danger to Earth’s
inhabitants not only by contaminating the near outer space environment, but
also as a threat during failed launches (as per the Challenger), and as
failed satellites that can crash back to Earth’s atmosphere due to
malfunction or collision with space debris. For those ASATs and
anti-ballistic missile weapons using nuclear detonation as the source of
energy for the weapon, the nuclear material on the space platform will itself
be vulnerable to attack from adversary ASATs and further threaten Earth’s
environment and inhabitants during conflict and thereafter, as that material
could eventually crash back to Earth if dispersed because of satellite
destruction.
Unfortunately this nuclear threat is not the only one associated with ASATs.
The power for some of the directed energy weapons will come from nuclear
reactors stationed in space, the weapon energized by a huge burst of nuclear
material fissioning, like in a nuclear powered electric generating plant.
This threat is further exacerbated by space-based ASATs, weapons satellites
that will be powered by nuclear reactors for the day-to-day electrical needs,
running the radar, the communications with the ground station and other
satellites, on-board computers, and so forth. Satellites with these reactors
will have to be launched, positioned in orbit, and maintained perfectly! Any
mistake, however small, could have nuclear material, mostly Plutonium, a very
chemically toxic and highly radioactive isotope, raining back down to Earth,
polluting the Earth’s surface for generations. Note that this has happened
with two Soviet spaced-based nuclear reactors. Malfunctions happened and
these reactors crashed back to Earth, burned up in atmosphere, and spread
nuclear materials over the face of Earth.
All future ASAT systems are not the very high tech Star Wars types of the Reagan era. Low(er) tech novel solutions are planned with some ready now. For example the Shuttle has satellite recovery ability evidenced by the Hubble repair effort. The captured Hubble could just as well have been an adversary’s spy satellite. Prepositioned space mines detonated when the offending satellite gets close are possible. A terrorist or military attack against a ground control station could disable a satellite just as effectively as an attack against the orbiting satellite. Unmanned satellite recovery is not beyond possibility. Recall that Mars was recently visited by robots.
Electronic signal manipulation is another major class of ASAT weapons effort. The signal to the satellite can be disrupted with a very loud, ‘electronic,’ competing signal. It is thus, ‘jammed.’ The signal to the satellite can be changed with incorrect information replacing the correct information. This is called "spoofing."
A significant and detailed argument about whether ASATs will work can be found in Stares, Space and National Security and The Fallacy of Star Wars by the Union of Concerned Scientists and revolves around the issue of increasing satellite survivability, the process of making a satellite less vulnerable to ASAT attack. An assessment of the argument requires one mentally consider satellites and ASATs in an all out go-for-broke, third world war, no-holds-barred scenario. ASATs will probably work, will be able to shoot down satellites. But, every shot will not result in a satellite kill, and to the extent that the designers have "hardened" their satellite, the satellite will last just that much longer, until, designs of the ASATs can be changed to overcome the hardening.
The methods used to "harden" or ‘increase the survivability of a satellite’ include some of the following:
Lasers using a variety of energy sources are currently being both developed and tested. Lasers can operate from the Earth, from the atmosphere, or from space. All three are being developed. The Mid-Infrared Advanced Chemical Laser (MIRACL) was tested in October, 1997. Reports on its success indicate that the operators were positive about the outcome. It was tested against an Air Force satellite and was said to have followed the satellite successfully for 30 km.. The test seems to really have been on the equipment that tracks and targets the satellite. This is a device called the SeaLite Beam Director (SLBD) and it is a the critical component of the laser. The laser makes the light. Getting it onto the target for the length of time required is the harder task. The satellite is moving very fast so that tracking and targeting the satellite successfully is vitally important. The SLBD is a large chunk of metal and electronics weighing 28,000 pounds! The MIRACL is itself a large structure. It is like a large combustion engine. It is a large combustion engine, also weighing tons and presently is rated at 2+ megawatt. Calculations, considering hardening techniques of new materials, indicate the power requirements may need to be raised by several orders of magnitude. This implies much larger chunks of equipment to be lifted into space, and most important, power sources, increasingly large nuclear reactors with large loads of radioactive isotopes that can fall back to Earth and contaminate the Earth and atmosphere.
The plan is to put a laser into a Boeing 747. When that effort is successful, size considerations will mean that the space-based laser will not be long in becoming a reality. Although part of the ballistic missile defense effort it will have satellite kill capacity and will therefore be a potential ASAT weapon as well.
The following is a list of some of the books used and unfortunately are not at all up-to date but have a lot of good history and more physics than most can follow.
By Gil Marshall
Gainesville, Florida
