Mystery object appears next to Shijian-21 in geostationary orbit
(06 Nov 2021) The U.S. Space Force's 18th Space Control Squadron (SPCS) has catalogued a new, somewhat mysterious object alongside China's recently launched Shijian-21 satellite.
According to state state media, the spacecraft will be mainly used to test and verify space debris mitigation technologies, which is somewhat remarkable as the main problem with space debris lies not in geostationary but in low-Earth orbit.
Western observers speculated that the spacecraft could rendezvous with and attach to another one for refuelling and repair, noting the same technology may also be used to disable spacecraft of adversaries.
Shijian-21 has meanwhile arrived in geostationary orbit (GEO) – and is now followed by a separate spacecraft. Catalogued under 49382/2021-094C, it is currently marked as apogee kick motor (AKM) in U.S. tracking data.
According to Wikipedia, "An apogee kick motor is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit."
However, separate AKMs are nowadays hardly ever used for launches into GEO. And of course they should manoeuvre out of the way to make sure they don't collide with the satellite after separation.
This is not the case here; apogee and perigee of the two objects are only about a kilometer apart. An educated guess is to assume that object 2021-094C is a secondary spacecraft that is to be used for testing proximity operations.
As almost always, this could be used for harmless civilian – even commercial – purposes as well as for military operations. It may also be remembered that both Russia and the U.S. have tested similar technologies.