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“Your association has taken a significant role in fostering public awareness of nuclear disarmament and has led to its advancement.”
– Kazi Matsui
Mayor of Hiroshima
June 2, 2022
Letter to the Editor
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Mark Avrum Gubrud

As Geoffrey Forden (“After China’s Test: Time for a Limited Ban on Anti-Satellite Weapons,” Arms Control Today, March 2007) indicates, space arms control has been stalled for many years, primarily by U.S. refusal to engage in negotiations or even less formally discuss the subject with other countries. Following China’s successful test of a direct-ascent, kinetic-energy anti-satellite weapon (ASAT), a number of analysts have proposed a ban focused narrowly on that type of weapon. Forden, in his piece, proposes restricting kinetic-energy and laser ASATs but leaving other technologies unaddressed.

Some strong arguments support proposals to focus attention on kinetic energy ASATs. Such weapons, which directly strike targets at high speeds, create large amounts of persistent orbital debris, an increasingly serious threat to all traffic in space. China’s addition to the debris burden has been condemned worldwide and has raised the concern that further tests, or a war in space using such weapons, might render space unusable for military or civilian purposes. The U.S. military shares this concern, has not tested a kinetic-energy weapon against an orbital target in over two decades, and apparently does not plan to do so in the future. Given that at least a live-impact testing ban would be highly verifiable (since it is impossible to hide the debris shower), the U.S. military might not object to such a ban, particularly if framed as a debris-control measure rather than as arms control.

Yet, even in the absence of such a ban, China will likely judge that the public relations costs of further orbital impact tests outweigh any military gains. As Forden states, the weapon can be tested adequately in close flybys, including at high (e.g., geosynchronous) altitudes, and can be impact tested against suborbital targets, at high closing speeds as the United States does, with its missile defense tests.

Forden proposes criteria that would ban the former but would permit the latter. Under such rules, terminal homing systems could be perfected openly. Intermediate-range target acquisition and tracking systems could be tested in low-closing-speed rendezvous operations, since high-speed flybys are not needed to verify their performance at the required updating rates. Thus, the further development of kinetic-energy ASAT technology would not be blocked.

More importantly, such proposals ignore the most significant technological trend in space weapons and military space power today: the development of small, autonomously maneuvering satellites. These “microsatellites,” or “nanosatellites,” have been advertised as experiments toward robotic servicing and refueling of satellites, anti-ASAT defenses, and even debris clearing. The feasibility and economics of such uses, however, are far more dubious than the usability of such vehicles for surveying, monitoring, inspecting, and actively probing foreign satellites and, if a decision is made to do so, interfering with, quarantining, damaging, or destroying satellites by a variety of means, without necessarily creating debris.

Such weapons, by definition, make their final approach at low closing speed, yet they need not take much longer than direct-ascent kinetic-energy ASATs to insert into orbits in close proximity with their targets. Since they might be capable of disabling actions that could be reversed and since they might be used first to inspect a target and decide if it is dangerous, they may be more likely to be used in a crisis. If sent to loiter near a potentially dangerous target, they might invite a preemptive attack on themselves, and their mere existence may provoke potential adversaries to equip future satellites with the needed “defensive” weapons.

Although there is little evidence to support claims that China has already deployed microsatellite space mines, the technology is certainly within reach of China and other space-faring nations. Chinese capabilities in this area will become an increasing concern for the U.S. military if Beijing follows the U.S. example by developing and testing highly maneuverable, miniature robotic vehicles whose use as weapons is an obvious possibility.

To prevent an arms race in space, arms control needs to stand in the way of the most important current and future developments in anti-satellite technology. Orbital proximity systems need not be banned but should be subject to accountability, openness, and verifiable technical limits designed to distinguish them from “co-orbital ASATs” and to control the latter. A kinetic-energy ASAT test ban would be simpler but would not significantly constrain current U.S. space weapons development plans, which others will likely follow.

Mark Avrum Gubrud is a graduate research assistant in experimental physics at the University of Maryland.


 

Geoffrey Forden Responds:

I agree with many of the points that Mark Avrum Gubrud makes in his letter. Where we differ most, or so it appears to me, is in the matter of pragmatism. I firmly believe that the time is ripe to outlaw an entire class of weapons: those based on kinetic, hit-to-kill technology, which have no legitimate use. Furthermore, we can ban these weapons from even being developed rather than “merely” agreeing to a ban on their use.

Gubrud, by contrast, suggests that there should be a way of banning robotic technology used in close proximity to other satellites, which he suggests are uneconomical in any case. I cannot comment on the economics of such activities, but I can give an example where they would clearly be desirable. Consider the plan of rescuing the Hubble Space Telescope by having a robotic vehicle rendezvous with the crippled satellite and boost it into a higher orbit, perhaps even fixing it. Such a robotic mission would be much more desirable than having a team of astronauts risk the 2 percent chance of a catastrophic accident associated with a shuttle flight.

While a code of conduct or even a treaty could pledge every space-faring nation to refrain from using such as system as a weapon, it could not prevent it from being developed, tested, or deployed. Nor should it; the trouble with dual-use technology is that its peaceful applications are often too valuable to ban outright.

I had many things in mind when I stated that kinetic-kill ASATs were the most dangerous form of space weapon. Given the relative lack of military utility for ASATs, however, the most relevant is the problem of persistent debris. The January Chinese ASAT test alone increased by at least 50 percent the likelihood of any low-Earth-orbit satellite being destroyed by an unintended collision. The world cannot afford the luxury of letting these weapons be developed.

Finally, I think it is a mistake to apply the adjective “direct ascent” to the Chinese weapon since it masks the real sophistication and range of the system. It is true it struck its target directly after being released from a suborbital launch vehicle. It could just as easily have been mounted on one of China’s rockets capable of inserting a satellite into geostationary orbit, a mission that would have involved first a parking and then a transfer orbit. If it had, it would have been able to hit strategically more important communications satellites.

Geoffrey Forden is a research associate with the Science, Technology, and Society Program at the Massachusetts Institute of Technology. He served as chief of the multidisciplinary analysis section of the UN Monitoring, Verification and Inspection Commission (UNMOVIC).