The Shijian-21 ‘space debris mitigation satellite’ docked with a dead satellite last month and elevated it to a less crowded orbit. The achievement made China the second country after the United States to demonstrate this capability.
According to an article on Space News, the defunct Beidou-2 navigation satellite had been orbiting in the geostationary belt, some 36,000km above the equator. This is a popular and valuable orbit as it allows satellites to remain directly above a fixed point on the Earth’s surface.
The Shijian-21 connected, then performed an engine burn to lift the satellite a further 3,000km to a graveyard orbit. Commentators noted that the elevation was significantly above the usual graveyard, which is 300km above geostationary.
The Shijian-21 had been conducting sophisticated rendezvous operations with objects in the geostationary orbit belt since it launched in October 2021. After it raised the orbit of Beidou-2, it then returned to the geostationary belt.
For more on the growing hazards of crowded orbital belts and some of the projects being undertaken to mitigate risk, see Engineering Matters episode #128 Positioning Satellites in New Space.
