China might have successfully collected the first lunar samples in more than four decades but recovering them once they arrive back on Earth will not be easy, its space authorities say.
The re-entry capsule of the Chang’e 5 spacecraft is expected to land on the snow-covered grassland of northern China’s Inner Mongolia autonomous region early on Thursday morning. It will be carrying about 2kg (4.4lbs) of rocks and dust collected from a volcano on the moon.
“The control [of re-entry] will be extremely difficult,” Bian Hancheng, the commander of the recovery team at the Jiuquan Satellite Launch Centre, told state broadcaster CCTV on Wednesday.
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Six military helicopters would use heat-seeking devices to try to track the capsule as it fell from the sky above Dorbod banner – close to the region’s border with Mongolia – and once they had a confirmed sighting, a ground team would be alerted and race to the touchdown site, he said.
To put the scale of the search mission into context, the capsule is about the size of a standard dining table, while the banner covers an area similar to that of Belgium.
Bian said there was also a chance the capsule might miss the landing zone altogether because of the high speed at which it was hurtling and the effect on its trajectory as it hit the Earth’s atmosphere.
The ground team would also have to overcome poor visibility if the capsule landed before sunrise and negotiate dirt tracks buried under 14cm (5.5 inches) of snow, he said.
According to state media reports, the mission team have conducted five drills in temperatures lower than minus 20 degrees Celsius (minus four degrees Fahrenheit) over the past few weeks.
The lunar samples – the first to be collected since Russia carried out a similar mission in 1976 – are being carried in a metal canister; but this could be damaged, causing the contents to leak out during re-entry, the CCTV report said.
The weather might also be a problem. Inner Mongolia has seen three times its average snowfall this winter, while strong winds from the arctic could blow the capsule more than 100km (62 miles) off course, it said.
Bian said the mission team had identified almost 3,000 potential hazards – from high-voltage power lines to communication towers – and was hoping the spacecraft could manage to avoid them all.
Several European tracking stations would provide data on the capsule’s final approach to help monitor its position and descent trajectory, he said.
“If the entire mission of Chang’e 5 was a relay, the search and recovery effort will be the final sprint,” Bian said.
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