China’s first satellite-to-satellite refuelling test appears to be imminent after a second round of close-proximity operations between two probes in high orbit on Monday.
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The landmark Chinese mission will be one of the most ambitious attempts at autonomous satellite servicing in geostationary orbit, which rival the United States has yet to achieve.
On Monday, the Shijian-21 and Shijian-25 spacecraft – both orbiting at an altitude of 35,786km (22,236 miles) above the equator – came within extremely close range after days of closing in on each other, according to Swiss space surveillance firm s2a Systems.
The optical tracking image shows the two satellites nearly indistinguishable from each other, suggesting they may be about to attempt docking and potentially even conduct the refuelling and servicing test that is the primary mission of the Shijian-25.
The two satellites had a similar encounter on June 13, when they reportedly came within 1km of each other before separating 90 minutes later. That manoeuvre could have been a rehearsal for docking, or an aborted attempt at docking, according to US-based space situational awareness software company COMSPOC.
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Space race elevates Asia in new world order
Space race elevates Asia in new world order
The Shijian-25 was designed to test “on-orbit refuelling and satellite life-extension technologies”, Chinese state media reported when the probe was launched in January. It said the mission aimed to verify capabilities for maintaining and prolonging the operational lifespan of satellites already in orbit as a way to reduce costs, improve sustainability and to help address growing concerns over space debris.