Governments consider their space programmes a matter of national security, so rarely share specific information about missions. Little is therefore known about China’s Long March 5B rocket, which recently put the core Tianhe module of the Chinese space station into orbit, beyond that its main section is now circling Earth at ever-lower levels and is expected to slam into the atmosphere in coming days. At that point, it is likely to break apart and burn up, although as it weighs 21 tonnes, pieces could fall to the ground. Ever greater numbers of launches by countries mean that this is not an unusual event beyond the size of the expected debris, but Washington’s intense rivalry with Beijing has turned it into an excuse for geopolitical point-scoring. United States Defence Secretary Lloyd Austin portrayed the rocket as a threat to life and property and suggested his country could shoot it down if necessary. “We’re hopeful that it will land in a place where it won’t harm anyone,” he said, then indirectly criticised Beijing by adding that there was a need “to make sure that we take those kinds of things into consideration as we plan and conduct operations”. The foreign ministry assured yesterday that the descent was being closely monitored , risks were low and China would give regular updates. Another Long March 5B broke up on re-entry last year and parts reportedly fell on a rural area in Ivory Coast. There are millions of pieces of junk and scores of satellites no longer operational orbiting the Earth. Most are destined to circle uncontrollably for years, but those in lower orbit gradually descend and parts that do not burn up fall to Earth. Although this happens regularly, there are no accounts of people being hit or severe damage caused. With 70 per cent of the Earth’s surface covered by water, most pieces fall into seas or oceans. US officials claim American rockets do not pose a threat as stages are always safely disposed of. China’s space agency has not indicated whether the Long March 5B is controlled or if debris will fall uncontrollably. There is no evidence Beijing is acting irresponsibly in space. Global cooperation is necessary to deal with space junk as more nations look skywards.