The United States has long recognized the importance of satellites in support of its economy and national security, especially global commitments beyond the horizon where satellites can still see and communicate. Its strategy to deter space war has essentially been unchanged since Russia developed a ground-launched anti-satellite weapon (ASAT) in the 1960s.

The current US strategy for "preventing and deterring aggression against space infrastructure" including satellites, as stated in the National Security Space Strategy, has five elements:

■"Support diplomatic efforts to promote norms of responsible behavior in space."

■"Pursue international partnerships that encourage potential adversary restraint."

■"Improve our ability to attribute attacks."

■"Strengthen the resilience of our architectures to deny the benefits of an attack."

■"Retain the right to respond, should deterrence fail."

Even when China successfully conducted a ground-launched ASAT in 2007, the US strategy remained adequate. A ground-launched ASAT would take more than an hour to reach the geostationary orbit where many important US satellites fly.

One might be concerned that a ground-launched ASAT could reach and kill a critical satellite in low-Earth orbit within tens of seconds. Fortunately, killing more might have to wait for hours, because a low-Earth-orbit satellite will only fly over a given launch site twice a day and a ground-launched ASAT needs the target to be in view.

Since this threat has existed for half a century and the US strategy has not changed, the United States must have considered the inherent time delay in ground-launched attacks long enough to defend against follow-on, if not the first, attacks.

On the contrary, the recent, little-publicized Chinese close proximity operations in space are a game changer, and avoiding a space war, which can spread to Earth, needs a new approach.

In its "Annual Report to Congress: Military and Security Developments Involving the People's Republic of China 2012," the Department of Defense states that: "Over the past two years, China has also conducted increasingly complex close proximity operations between satellites while offering little in the way of transparency or explanation."

The annual reports for 2013, 2014 and 2015 repeat an identical warning that People's Liberation Army writings emphasize the necessity of destroying, damaging and interfering with the enemy's critical satellites.

Close proximity operations can be used for peaceful missions, such as repairing or resupplying satellites and space stations, or military missions, such as seizing and destroying satellites. This dual-use characteristic can provide a cover for developing and placing these ASATs in orbit during peacetime.

If China tried to seize Taiwan, or engaged in other conflicts in East Asia, these prepositioned space objects could be maneuvered to essentially tailgate US satellites. China could use such a configuration to deter US intervention by demonstrating that its space stalkers could practically simultaneously attack several critical satellites from such a close proximity that the US would not have time to protect them.

Under such a threat, the US might be forced to preemptively destroy China's space stalkers.

The fifth element of US strategy is to "retain the right to respond, should deterrence fail." Unfortunately, after the attacks, US response would be too late to save the target satellite capabilities that it needs.

For the last five decades, the US has been silent about whether it would exercise self defense pre-emptively. The US needs to let the world know in peacetime, not at the eve of pre-emption, why pre-emption might be necessary under this close-proximity threat. Otherwise, even US allies might condemn the US for firing the shot that started a space war.

The direct solution is to ban space-based ASATs but this requires a distinction between space-based ASATs and satellites — a distinction that cannot reliably be made once they are in orbit. Even a garden-variety satellite can be maneuvered to hit another satellite, thus, banning space-based ASATs would mean banning satellites as well.

Yet, China and Russia have been gaining support for their proposed "Treaty on Prevention of the Placement of Weapons in Outer Space," which is founded on this unreliable distinction. A resolution urging work on the proposed treaty was overwhelmingly approved in the UN General Assembly in December. The US needs to take three proactive steps.

First, declare publicly that the aggressor is the one displaying such a tailgating configuration and that the party making the first move, including pre-emption, is acting in self-defense.

Second, convince friendly nations to declare their support of this position.

Third, propose to add the prohibition of multiple space stalkers into UN outer space transparency and confidence-building measures. This would prohibit the positioning of more than an innocuous threshold number of space objects, perhaps two, three or four, to tailgate (or closely lead) another country's satellites. That number is high enough so no country would accidentally breach it conducting peaceful space activities, but also low enough so that destroying the same number of US satellites would not significantly impair US capabilities. This proposed measure based on threatening configurations is observable and verifiable.

This approach has been designed especially through the first two steps to speak out so that friendly nations would understand and support US action to conduct preemptive self defense under this specific threat.

Once a potential adversary recognizes that the one posing a threatening tailgating configuration would be treated as the aggressor and that the configuration would be defeated, the adversary would have no incentive to pose the threat in the first place. A space war would, thus, be avoided.

Brian Chow retired from the Rand Corp. in February after serving as a senior physical scientist for 25 years. He can be reached at

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