The two spacecraft – the Shijian-21 and Shijian-25 – have been docked some 36,000km (22,370 miles) above Earth since early July. Their mysterious mission was widely believed to involve the Shijian-25 supplying the Shijian-21 with propellant.
Last month, they executed what Lieutenant General John Shaw called “the largest single manoeuvre ever conducted in geosynchronous orbit”, shifting their track with a velocity change of more than 330 metres (1,083 feet) per second.
“That’s actually a lot, at least by today’s standards,” Shaw, a former deputy commander of the US Space Command, told senators at a hearing in Washington on Wednesday.
Observers said the manoeuvres would have burned the equivalent of six years’ worth of station-keeping fuel – the amount needed to keep a satellite steady in such a high orbit.
01:57
China’s Chang’e-6 mission returns to Earth with first samples from moon’s far side
China’s Chang’e-6 mission returns to Earth with first samples from moon’s far side
