China completed a weapons test on Sunday that entails destroying a ballistic missile as it arcs back into the earth’s atmosphere, risking creating a dangerous debris field in space. China said the test was not directed at any particular nation, but it comes in disregard for U.S. calls for countries to ban weapons tests in space.
On Sunday, the Chinese Ministry of Defense issued a statement announcing it had “conducted a land-based mid-course missile interception test” within its territory and said the test “achieved the desired objective.” While short on details about the precise nature of the test, a midcourse interception of a ballistic missile entails destroying it as it travels through or near the edge of space.
According to the U.S. Missile Defense Agency (MDA), ballistic missile trajectories are commonly divided into three phases: the boost phase, mid-course and terminal phase.
Missile interception in the initial boost phase is optimal as it would destroy a potentially nuclear-armed ballistic missile before it can deploy most countermeasures. While a boost-phase interception is optimal, there is only a narrow one to five-minute window of time for such an interception to occur and missile defense interceptors and sensors must be placed in close proximity to the missile when it launches.
The mid-course is a less desirable phase for intercepting a ballistic missile but provides as much as 20 minutes for such an interception to take place. During its mid-course flight, a ballistic missile’s boosters burn out and the missile follows a predictable arc through space. Stopping a ballistic missile in its mid-course phase entails destroying it in space, which runs the risk of creating a field of space debris that can endanger satellites and spacecraft.
The terminal phase is the least optimal time to stop a ballistic missile as it is the last chance to stop the missile and the interception will occur close to the intended target.
China’s inherently space-based weapons test comes as the U.S. has made recent calls for countries to ban weapons tests that can generate debris fields in space. In April, Vice President Kamala Harris announced the U.S. would ban direct-ascent anti-satellite missile testing.
“A piece of space debris the size of a basketball, which travels at thousands of miles per hour, would destroy a satellite,” Harris said. “Even a piece of debris as small as a grain of sand could cause serious damage.”
“Simply put: These tests are dangerous, and we will not conduct them,” she added. “We are the first nation to make such a commitment. And today, on behalf of the United States of America, I call on all nations to join us.”
The new U.S. policy against ASAT tests does not preclude the U.S. or other nations from developing weapons inherently intended to defend against potentially-nuclear ballistic missiles. Indeed, the MDA has developed and tested a number of mid-course ballistic missile interception systems including the Ground-based Midcourse Defense (GMD) and the sea-based element of the Aegis Ballistic Missile Defense system.
While anti-satellite (ASAT) missiles inherently serve a different purpose than missiles designed to stop ballistic missiles in mid-course flight, both weapons introduce the risk of generating space debris.
China’s Ministry of Defense said the latest test “is defensive in nature and not targeted against any country.”