Two Chinese satellites may have docked in geostationary orbit for a historic refuelling mission, an autonomous satellite servicing feat the United States has yet to achieve.
China’s Shijian-21 and Shijian-25 “appeared visually merged in optical sensor data” between July 2 and July 6, US-based space situational awareness software provider COMSPOC said on Saturday in a social media post.
“Given the prolonged RPO time, SJ-21 and SJ-25 may have docked,” it said, using the acronym for “rendezvous and proximity operations”.
The two probes were observed carrying out such operations in geosynchronous orbit in June and July “with multiple close approaches”, it added.
The first close approach was observed on June 11, when Shijian-25 continued its “steady drift towards” Shijian-21, and the two came within 1km (0.6 mile) of each other on June 13 before separating 90 minutes later, according to COMSPOC.
US surveillance satellites USA 270 and USA 271 flanked the Chinese satellites from east and west at the time and were positioned for optimal viewing angles, the company said.
According to optical tracking images from Swiss space surveillance firm s2a systems, the Chinese satellites, both orbiting at an altitude of 35,786km (22,236 miles) above the equator, carried out another round of close-proximity operations on June 30.
