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Last Thursday was apparently garbage day at the International Space Station, which got rid of a 2.9-tonne pallet of used nickel-hydrogen batteries. It is the largest mass of space debris unleashed by the ISS, and NASA wrote that the pallet “moves safely away from the station and will orbit the earth for between two to four years before burning harmlessly into the atmosphere.” How big it is, a NASA representative tells Gizmodo that the hunk “is more than twice the mass of the Early Ammonia service system tank that was submerged by space traveler Clay Anderson during the 2007 STS-118 mission. . ” Syfy explains that this was not the original plan. Japanese H-II transfer vehicles (HTV) disposable vehicles were replacing the old batteries with lithium-ion batteries, and each HTV would fall back to earth with a battery pallet on board. The objects will burn during re-entry, with any remains falling into the South Pacific.
Why this pallet was rather removed from the ISS, you blame the ‘ripple’ effect of an emergency landing in 2018 that hit the ISS’s disposal grid, reports Syfy. Spaceflight Now explains that astronaut Nick Hague was supposed to take part in the battery exchanges, but his failure to reach the ISS eventually led to one pallet of batteries that could not be detected by an HTV. However, bad astronomy blogger Phil Plait is not convinced of the long-term success of this plan, and tweeted Thursday, “It strikes me (haha, a pun given the circumstances) as dangerous. It looks big and dense, so unlikely it will burn up completely.” Astronomer Jonathan McDowell agrees in an answer: tweet, “Yes. On the other hand, e.g. Tiangong-1, was 7500 kg, much larger. But I would say given how dense EP9 is, it goes, even if it’s at the bottom of the matter.” The U.S. Space Command will monitor cases. (Read more stories about the International Space Station.)