Why We Need to Avoid More Anti-Satellite Tests
An Indian PDV-Mk II missile lifts off March 27 en route to intercept and destroy Microsat-R.
(Image: © Government of India)
India announced three weeks ago that it had joined an “elite club of space powers,” having destroyed one of its own satellites with a hit-to-kill missile defense interceptor. With “Mission Shakti,” India became the fourth country to intentionally destroy a satellite on orbit.
Only three other states—the Soviet Union, the United States, and China—have deliberately destroyed orbiting satellites. No state has destroyed another state’s satellite. This extraordinary restraint is worth preserving and expanding.
While India’s rationale for the test undoubtedly included pleasing domestic audiences and signaling military strength, India’s decision to use its missile defense interceptor against a satellite rather than a missile has wider ranging implications. Because midcourse missile defense systems are intended to destroy long-range ballistic missile warheads, which travel at speeds and altitudes comparable to those of satellites, they also have inherent anti-satellite (ASAT) capabilities. This test again makes that inherent capability explicit. Indeed, China used a hit-to-kill interceptor to destroy the Fengyun-1C satellite in 2007, and thereafter tested the system against missile targets. The United States followed suit the next year by destroying the USA-193 satellite with an interceptor from the Aegis missile defense program.
The Indian government characterized the Mission Shakti test as responsible because its target was at such a low altitude that all the debris would flush out “within weeks.” However, the kinetic energy of hit-to-kill intercepts can kick debris pieces into new, higher orbits, which increases the debris lifetime and allows it to threaten other satellites. So far, around 50 pieces of trackable debris from Mission Shakti have been identified as reaching apogees at or above the International Space Station. These are certain to be accompanied by smaller debris that are not trackable but could still be deadly in a collision. On April 1, NASA Administrator Jim Bridenstine decried the test and stated that this kind of activity is “not compatible with the future of human spaceflight.” Even “responsible” tests put other space users at risk.
The bigger concern, however, is that the use of destructive anti-satellite weapons in more typical orbits can create dangerous amounts of persistent space debris that can threaten the secure use of space for all users. Commercial and civil interests dominate even in low earth orbit, where eighty-five percent of satellites are nonmilitary.
Unlike at the low altitude of the Shakti test, destroying satellites at higher altitudes—which is likely if ASAT weapons are used in a military conflict—can create very large amounts of debris that persists for decades, or indefinitely. China’s destruction of the Fengyun-1C satellite in 2007 created thousands of pieces of catalogued debris, most of which remains in orbit. The Fengyun-1C satellite was modestly sized, about 750 kilograms. The destruction of a large satellite, such as a 10-ton military reconnaissance satellite, could easily double the amount of dangerous debris in low earth orbit at altitudes that are heavily used.
For these reasons, space-faring countries have incentives not to test or use debris-creating weapons. But self-interest is not an effective long-term strategy to deal with a growing arsenal of ASAT-ready technologies against a backdrop of increasing strategic competition in space. How big is the problem? Even setting aside other means of interfering with satellites, and looking solely at missile defenses, it is clear this is a serious issue.