Space station crew inspect mysterious hole during spacewalk
Drilled hole in Soyuz spacecraft caused air leak in space station in August
Spacewalking astronauts ripped through thick insulation on a capsule docked to the International Space Station on Tuesday, looking for clues to a mysterious drilled hole that leaked precious cabin air four months ago.
Russians Sergei Prokopyev and Oleg Kononenko spotted the tiny hole in the external hull of the Soyuz capsule, more than five hours into their gruelling spacewalk.
"That is exactly the hole we've been looking for, guys," radioed Russian Mission Control outside Moscow.
The spacewalkers reported seeing no drill marks around the black dot, like on the inside.
Back in August, the ISS crew patched the hole in the Soyuz capsule, plugging it with epoxy and gauze. Russian space officials wanted the site surveyed from the outside, before the capsule's return to Earth next week with Prokopyev and two others.
This part of the capsule will be jettisoned as usual before atmospheric re-entry, and so poses no risk for descent.
Prokopyev and Kononenko had to use a pair of telescoping booms to reach the Soyuz. It took nearly four hours for them to cross the approximately 30 metres to get there. Then the insulation proved harder to remove than expected, taking another one to two hours of effort.
The "eureka" moment. Spacewalkers find the "small black dot" where controllers believe the area of the fixed pressure leak is located on the Soyuz crew vehicle. <a href="https://twitter.com/hashtag/AskNASA?src=hash&ref_src=twsrc%5Etfw">#AskNASA</a> | <a href="https://t.co/yuOTrYN8CV">https://t.co/yuOTrYN8CV</a> <a href="https://t.co/NFNOIPTkW1">pic.twitter.com/NFNOIPTkW1</a>—@Space_Station
To expose the external hull, they cut away a 25-centimetre swatch of thermal insulation and debris shield. Bits of shredded silver insulation floated away like confetti, as the two slashed at it with a knife and long cutters. The astronauts collected samples of the black epoxy sealant protruding from the hole, just two millimeters across.
Their spacewalk lasted almost eight hours. "It is high time you went home," Mission Control urged.
"It was very difficult … but we were able to get it done," one of the spacewalkers said.
NASA said the pieces of freed insulation posed no threat to the space station and would likely burn up in the atmosphere in a day or so.
The capsule leak caused a flap between the U.S. and Russian space agencies, following its discovery at the end of August. Russian space chief Dmitry Rogozin observed that the hole could have been drilled during manufacturing — or in orbit. The space station's commander at the time flatly denied any wrongdoing by himself or his crew.
Rogozin has since backpedaled his statement, blaming the news media for twisting his words.
A Russian investigation is ongoing, according to Rogozin, and samples collected during the spacewalk will be returned to Earth on the Soyuz. The spacewalk findings could lead to better repair techniques in the future, officials said.
The Soyuz is scheduled to depart the orbiting lab on Dec. 19, with Prokopyev, American Serena Aunon-Chancellor and German Alexander Gerst, the station's current skipper. It ferried them up in June.
Remaining aboard the 400-kilometre-high outpost for the next six months will be American astronaut Anne McClain, Russian cosmonaut Oleg Kononenko and Canada's David Saint-Jacques, who arrived last week.
This was the 213th spacewalk in 20 years at the ISS.