Officials from NASA and Russia\u2019s space agency don\u2019t see eye to eye on the causes and risks of small but persistent air leaks on the International Space Station.<\/p>\n
That was the word from the new chair of NASA\u2019s International Space Station Advisory Committee last week. The air leaks are located in the transfer tunnel of the space station\u2019s Russian Zvezda service module, one of the oldest elements of the complex.<\/p>\n
US and Russian officials \u201cdon\u2019t have a common understanding of what the likely root cause is, or the severity of the consequences of these leaks,\u201d said Bob Cabana, a retired NASA astronaut who took the helm of the advisory committee earlier this year. Cabana replaced former Apollo astronaut Tom Stafford, who chaired the committee before he died in March.<\/p>\n
The transfer tunnel, known by the Russian acronym PrK, connects the Zvezda module with a docking port where Soyuz crew and Progress resupply spacecraft attach to the station.<\/p>\n
Air has been leaking from the transfer tunnel since September 2019. On several occasions, Russian cosmonauts have repaired the cracks and temporarily reduced the leak rate. In February, the leak rate jumped up again to 2.4 pounds per day, then increased to 3.7 pounds per day in April.<\/p>\n
This prompted managers to elevate the transfer tunnel leak to the highest level of risk in the space station program\u2019s risk management system. This 5\u00d75 \u201crisk matrix\u201d classifies the likelihood and consequence of risks. Ars reported in June that the leaks are now classified as a \u201c5\u201d both in terms of high likelihood and high consequence.<\/p>\n
NASA reported in September that the latest round of repairs cut the leak rate by a third, but it did not eliminate the problem.<\/p>\n
,<\/p>\n
\u201cThe Russian position is that the most probable cause of the PrK cracks is high cyclic fatigue caused by micro-vibrations,\u201d Cabana said on November 13. \u201cNASA believes the PrK cracks are likely multi-causal, including pressure and mechanical stress, residual stress, material properties, and environmental exposures.\u201d<\/p>\n
The ISS is aging. Zvezda and the PrK launched in July 2000 and will mark a quarter-century in orbit next year. NASA wants to keep the space station operating until at least 2030, while Roscosmos, Russia\u2019s space agency, has committed only through 2028.<\/p>\n
Roscosmos has shared sample metals, welds, and investigation reports with NASA to assist in the study of the cracks and leaks. In a report published in September, NASA\u2019s inspector general said NASA\u2019s ISS Vehicle Office at Johnson Space Center in Houston said the leaks are \u201cnot an immediate risk to the structural integrity of the station.\u201d<\/p>\n
This is because managers have implemented mitigations to protect the entire station in the event of a structural failure of the PrK.<\/p>\n
Crew members aboard the space station are keeping the hatch leading to the PrK closed when they don\u2019t need to access the Progress cargo freighter docked at the other end of the transfer tunnel. Russian cosmonauts must open the hatch to unpack supplies from the Progress or load trash into the ship for disposal.<\/p>\n
But NASA and Roscosmos disagree on when the leak rate would become untenable. When that happens, the space station crew will have to permanently close the hatch to seal off the PrK and prevent a major failure from affecting the rest of the complex.<\/p>\n
,<\/p>\n
\u201cThe station is not young,\u201d said Michael Barratt, a NASA astronaut who returned from the space station last month. \u201cIt\u2019s been up there for quite a while, and you expect some wear and tear, and we\u2019re seeing that.\u201d<\/p>\n
\u201cThe Russians believe that continued operations are safe, but they can\u2019t prove to our satisfaction that they are,\u201d said Cabana, who was the senior civil servant at NASA until his retirement in 2023. \u201cAnd the US believes that it\u2019s not safe, but we can\u2019t prove that to the Russian satisfaction that that\u2019s the case.<\/p>\n
\u201cSo while the Russian team continues to search for and seal the leaks, it does not believe catastrophic disintegration of the PrK is realistic,\u201d Cabana said. \u201cAnd NASA has expressed concerns about the structural integrity of the PrK and the possibility of a catastrophic failure.\u201d<\/p>\n
Closing the PrK hatch permanently would eliminate the use of one of the space station\u2019s four Russian docking ports.<\/p>\n
NASA has chartered a team of independent experts to assess the cracks and leaks and help determine the root cause, Cabana said. \u201cThis is an engineering problem, and good engineers should be able to agree on it.\u201d<\/p>\n
As a precaution, Barratt said space station crews are also closing the hatch separating the US and Russian sections of the space station when cosmonauts are working in the PrK.<\/p>\n
\u201cThe way it\u2019s affected us, mostly, is as they go in and open that to unload a cargo vehicle that\u2019s docked to it, they\u2019ve also taken time to inspect and try to repair when they can,\u201d Barratt said. \u201cWe\u2019ve taken a very conservative approach to closing the hatch between the US side and the Russian side for those time periods.<\/p>\n
\u201cIt\u2019s not a comfortable thing, but it is the best agreement between all the smart people on both sides, and it\u2019s something that we as a crew live with and adapt.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
Officials from NASA and Russia\u2019s space agency don\u2019t see eye to eye on the causes and risks of small but persistent air leaks on the International Space Station. That was the word from the new chair of NASA\u2019s International Space Station Advisory Committee last week. The air leaks are located in the transfer tunnel of […]<\/p>\n","protected":false},"author":1,"featured_media":44594,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1545,717,190,234,352],"class_list":["post-44592","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-human-spaceflight","tag-international-space-station","tag-nasa","tag-roscosmos","tag-russia"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/44592"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=44592"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/44592\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/44594"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=44592"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=44592"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=44592"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}