China's Shijian-21, spacecraft, pulled a defunct satellite well above graveyard orbit
Shijian-21 has started its rendezvous and proximity operations (RPO) in October last year. This work resulted in Shijian-21 docking with the dead Beidou-2 G2 navigation satellite and hauling it 36,000 kilometres above the equator above the congested band of geostationary orbit.
According to Brien Flewelling of ExoAnalytic Solutions, who spoke during a webinar organised by the Center for Strategic and International Studies (CSIS), Shijian-21 completed a big burn on January 22, putting the Beidou-2 G2 satellite 3,000 kilometres over the GEO belt.
The docking and following engine burn — which was exceptionally massive, propelling it beyond the typical "graveyard" orbit of 300 kilometres above GEO — essentially pushed it out of harm's way.
Beidou-2 G2 failed in orbit after its launch in 2009, has been drifting since 2010, and may have disintegrated at some time.
Shijian-21 is a space debris mitigation spacecraft with a robotic arm, according to China. Despite this, the satellite's creator, the state-owned China Aerospace Science and Technology Corporation (CASC), did not reveal any information about it or its intended missions following its successful launch. The mission's clandestine nature may have some military stakeholders or aims.
While trash removal and on-orbit servicing are becoming more common to extend the lifetimes of satellites, the same activity might be employed for military purposes to destroy or otherwise interfere with a satellite.