NASA Lifts Brief Ban on U.S. Spacewalks
NASA astronaut Peggy Whitson, Expedition 16 commander, works with an Extravehicular Mobility Unit (EMU) spacesuit in the Quest Airlock of the International Space Station.
Credit: NASA.

NASA lifted a brief ban on U.S. spacewalks outside the International Space Station (ISS) Thursday after engineers cleared the orbital laboratory's spacesuits of potential fire-hazards, space agency officials said.

The decision allows ISS Expedition 16 commander Peggy Whitson and flight engineer Dan Tani to proceed with preparations for two critical spacewalks next week to continue space station construction.

NASA temporarily suspended U.S. spacewalks earlier this week after an astronaut smelled smoke inside a U.S. spacesuit - known as an Extravehicular Mobility Unit (EMU) - during a ground test at the agency's Johnson Space Center (JSC) in Houston, Texas. The ban was largely a precaution in case the incident was due to a generic flaw in NASA spacesuits.

"They had overwhelming data that showed there was no evidence of a combustion event," NASA spokesperson Lynette Madison, of JSC, told SPACE.com.

While engineers have not completely identified root cause of the Earth-based suit's smoky odor, the leading candidate is the specific canister used to sift carbon dioxide from the EMU's 100 percent oxygen interior, she added.

But engineers were able to clear the spacesuits to be used by Whitson and Tani during their planned Nov. 20 and Nov. 24 spacewalks of any concerns.

"The EMUs have the go for spacewalk use," stated an ISS Expedition 16 status report issued today. Because of the high flammability of a spacesuit's oxygen-rich atmosphere, NASA takes any hint of smoke or combustion seriously to ensure the safety of spacewalking astronauts.

Whitson and Tani recharged the water supplies for their EMUs while working aboard the space station earlier today. Two cooling system radiators were also deployed outside the ISS. The Expedition 16 crew plans to outfit the station's recently installed Harmony module with cooling and power lines during the upcoming spacewalks, which will cap a busy month of work to move the school bus-sized connecting node to its final perch at the front of the outpost's U.S. Destiny laboratory.

Madison said NASA also approved plans today to go ahead with a series of spacewalks scheduled for December's STS-122 shuttle mission to attach the European-built Columbus laboratory to one of Harmony's multiple docking ports. The Italian-built Harmony node is designed to serve as the anchor for European and Japanese laboratories at the ISS.

Commanded by veteran shuttle astronaut Stephen Frick, the seven STS-122 astronauts are slated to launch toward the ISS aboard the Atlantis orbiter on Dec. 6 to begin their 11-day construction mission.

A preliminary meeting found the mission to be on track for its December launch earlier this week, with a final flight readiness review set for Nov. 30, NASA spokesperson Kyle Herring said.

NASA will broadcast the Expedition 16 crew's second spacewalk outside the ISS live on NASA TV on Nov. 20 beginning at 5:00 a.m. EST (1000 GMT). Click here for SPACE.com's ISS mission updates and NASA TV feed.

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