NASA delays spacewalk a 2nd time due to leak on International Space Station

NASA officials have again postponed one of two forthcoming spacewalks in the wake of a recent coolant leak on the Russian segment of the International Space Station.

A spacewalk last set for Thursday (Oct. 19) will now happen later in 2023 as NASA and Russia's federal space agency, Roscosmos, continue their analysis, NASA officials stated. The coolant used on the International Space Station (ISS) is ammonia, which requires extra decontamination procedures if spacesuited astronauts are nearby.

The leak in Russia's Nauka science module started and stopped on the same day, Oct. 9, but the cause is still unknown at this time. It's the third time that Russian ISS equipment has leaked ammonia in the past year. Roscosmos plans its own spacewalk on Oct. 25 to examine the 13-year-old relocated radiator from the Rassvet module up close, from which the newest leak on Nauka appeared to originate.

"The coolant is not toxic or hazardous for the crew, but experts are discussing how to best keep small traces of the substance from getting into some internal systems to avoid equipment degradation over time," NASA officials wrote in a blog post Monday (Oct. 16). "The schedule adjustment has no impact on space station operations," they added, saying that is because the work is not "time-sensitive."

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NASA's pair of spacewalks are both focused on minor maintenance tasks. The first postponed spacewalk (already delayed a few days due to the leak) will include NASA astronaut Loral O'Hara and European Space Agency astronaut Andreas Mogensen. They will collect samples to search for microorganisms on the ISS exterior, and replace a high-definition camera, among other fixup duties. An exact date for that work will be determined later.

So far the second spacewalk of the NASA set, a rare all-woman spacewalk now scheduled for Oct. 30 following its own delay due to the leak, is still expected to go forward on that date. O'Hara will be joined by NASA astronaut Jasmin Moghbeli on only the fourth-ever all-woman spacewalk, following a trio by NASA astronauts Christina Koch and Jessica Meir in 2019 and 2020. Moghbeli and O'Hara will remove a faulty electronics box and replace a bearing needed for one of the station's solar arrays.

Russia has said that the other two ammonia leaks on the ISS are due to micrometeroid strikes. The first leak, in December 2022, damaged a Soyuz spacecraft so badly that its crew was reassigned to a replacement Soyuz. Fixing the matter took several spacecraft shipments and forced the three astronauts to double their six-month stay to a year. A Russian Progress spacecraft for cargo sprung its own leak as well in February 2023.