China's Shijian-21 and Shijian-25 satellites prepare for potential convergence and docking in geostationary orbit (GEO), which may be China's first demonstration of refueling a satellite at such an altitude.
According to COMSPOC, which monitors the space environment, both devices are currently about two degrees of longitude apart (about 1 500 km) from each other. Simultaneously, American surveillance satellites of the USA are located near this pair 270 and USA 271 from the GSSAP program, which record the maneuvers of Chinese apparatuses.
Companion Shijian-21, Running in 2021 year, previously successfully completed the mission of towing the used Beidou-2 G2 navigation satellite to the "satellite graveyard". It has been passively drifting in orbit for the past year, however, recently began active maneuvers in the direction of Shijian-25 — the device, launched in January of this year to test refueling technologies and extend the service life of satellites.
The satellites are currently moving in a phased orbit — their orbital parameters are almost identical, however, they remain at a certain distance from each other, which allows docking with minimal fuel consumption. Expected, that convergence will occur 11 June, although the Shijian-25 can reduce the approach speed in the final phase.
Shijian-25 maneuvers were recorded in the period from 6 by 8 June and included at least four orbit changes. In Chinese sources, the Shijian-25 is described as an apparatus, created to "refuel and continue missions". So, Shijian-21 is likely to be the first refueling target in this demonstration.
The operation is being monitored not only by the Chinese side. American satellites of GSSAP — USA 270 і USA 271 — are located on both sides of the Chinese devices. This allows them to capture approaches with favorable lighting angles, providing detailed monitoring with a minimal shadow area.
This presence of American satellites adds complexity to the regional space situation and increases the level of strategic monitoring in GEO, where important defense and commercial communications satellites are traditionally located.
This case is not the first example of satellite maintenance in geostationary orbit. IN 2020 Northrop Grumman successfully docked with the Intelsat IS-901 satellite using the MEV-1, extending his mission for five years. MEV-1 is currently preparing for its next mission with the OPTUS D3 satellite.