The Los Angeles Times and Aviation Week and Space Technology reported that the Chinese government launched a satellite intercept system in January 2007 using a ground based missile, and hit one of their own, aging, weather satellites. The satellite was in an inclined, polar type orbit, at over 500 miles altitude.
Av Week described the incident as a "test" of a satellite intercept system, which would probably mean that the interceptor had on-board sensing capability, navigation, and a course correction maneuvering system. The description of the intercept was depicted as a hit-to-kill impact, which would have meant no on-board explosives. On the other hand, a satellite intercept requires a precise sensor and course correction capability on the interceptor to make a direct hit. Space is a big thing and a hit-to-kill is challenging (although done before by the US some time ago).
The LA Times made it sound like the Chinese "took out" their satellite, which implies possible larger than hit-to-kill impact. The destruction would depend on the closing velocity of the interceptor. I suspect the LA Times was using exaggeration just a little. Past analysis shows that the interceptor will damage a satellite through the kinetic energy of the impact. The US will now use it's space surveillance system to document and track the pieces of the satellite and interceptor after the impact.
Of primary concern is the debris field created by the impact. This altitude region, termed low earth orbit, contains many other satellites from many nations. Any impact on these satellites by the debris could be critical. Over time, the debris will re-enter the earth's atmosphere. But that could take years. The Space Shuttle, flying at a much lower altitude, ran into a paint chip (that was the analysis) and it created a crack in the windshield of the Shuttle. A tiny particle hitting a very solid Mach 20 capable windshield. The bottom line is that small particles can cause serious damage if they hit other satellites with significant velocity.
The other concern is the Chinese have now demonstrated satellite hit-to-kill capability. This potentially puts every low orbit satellite at hostage to the Chinese capability. This includes communication satellites (such as cell phone companies), weather satellites, intelligence gathering satellites, and satellites with other missions. That is potentially a very risky thing for the U.S.
We will have to see what transpires in the months ahead. I do know that the Chinese now have the full attention of the U.S. space planners.
