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Civil Satellite Vulnerability

Allen Thomson

Space News, 20-26 February 1995

Allen Thomson is a former Central Intelligence Agency analyst

Rapidly evolving space surveillance and anti-satellite (ASAT) technologies, along with world-wide knowledge of the tactical uses of satellite reconnaissance, navigation and communications systems, are creating an environment in which U.S. military satellites will come under increasing risk of attack from future adversaries.

This risk, however, is by no means limited to the military. The consequences of attacks against both civil and national security space systems should be carefully considered by companies operating and using space-based services, and by the U.S. Congress and the administration of U.S. President Bill Clinton.

Analysis of the use of space by U.S. and allied forces during the Gulf War reveals the enormous leverage an opponent possessing even rudimentary counter-satellite capabilities could exert. Similarly, examination of present and future civilian uses of satellites shows that a country able to destroy or degrade those systems would possess economic and political power over the United States.

Because vulnerability issues are often ignored in the design of civilian satellites, those systems may be especially tempting targets, as their destruction would avoid the level of political challenge inherent in attacks on national security satellites, and could be undertaken at low levels of conflict, or even before terrestrial warfare had begun.

The situation with respect to the low Earth orbit communications satellite systems, which represent a major business initiative by a number of companies and consortia, is particularly troublesome. These systems will consist of a large number of satellites representing billions of dollars in equipment and launch costs and will be at altitudes readily accessible to even modest conventional ASATs. The redundancy in large constellations will make the over-all systems somewhat resistant to loss of one or a few satellites, but even then the financial effect - both in terms of increased insurance rates and lost revenue due to customer concerns - would probably be substantial.

The possibility that a rogue country with a nuclear weapon might choose to use it as an ASAT is a more serious concern. In this case, not only would the satellites in the immediate vicinity of the explosion be destroyed, but the Van Allen belt would become an even more lethal environment for spacecraft electronics for months afterward. This would effectively wipe out unprotected multisatellite systems in low Earth orbit, with little or no hope of replacement for at least one or two years. It is doubtful any commercial venture could sustain so severe a loss and remain in business.

The West's options for deterrence against such an act are limited at present, since use of a nuclear ASAT will kill no one directly and does not involve an attack against the national territory of another state.

Further in the future, but probably no more distant than the first decade of the 21st century, it will be necessary to consider attacks against global navigation satellites such as the Global Positioning System

and Russia's Global Navigation Satellite System. Even more than low Earth orbit communications systems, global navigation satellite systems will support functions vital to society and involving the lives of thousands of people on a second-by-second basis. The recent drive to use augmented GPS for aircraft navigation and landing is an example of this trend; another is the impending use of GPS timing signals for synchronization of digital communications systems.

GPS incorporates elements of redundancy, dispersion and hardening that make it a more difficult target than low Earth orbit systems. But GPS is by no means invulnerable to advancing ASAT and counter-satellite technologies. Future, purely civilian, global navigation satellite systems may well be even more at risk.

If the government and industry wish to deal with the problems of civil satellite vulnerability, some of the response can be on the purely technical level. For example, satellites can be hardened to withstand the harsher ravages of the Van Allen belt after a nuclear explosion, though the additional expense may have to be borne by the public.

Technical responses to the ASAT threat are only part of the answer. Governments need to develop policies concerning the degree of reliance that should be placed on vulnerable systems for which there is no back-up, and on ways of deterring attacks on satellite systems. Development of effective policies must involve contributions from a variety of departments and agencies within the U.S. government, industry and allies.