NASA lifted a brief ban on U.S. spacewalks outside the international space station Thursday after engineers cleared the orbital laboratory's spacesuits of potential fire hazards, space agency officials said.
The decision allows 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, or EMU — during a ground test at the agency's Johnson Space Center in Houston. 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 spokeswoman Lynette Madison 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 remove carbon dioxide from the spacesuit's 100 percent oxygen interior, she added.
Engineers cleared the spacesuits to be used by Whitson and Tani of any concerns. Preparations are on track for their spacewalks next Tuesday and on Nov. 24.
"The EMUs have the go for spacewalk use," according to an Expedition 16 status report issued Thursday. Because of the high flammability of a spacesuit's oxygen-rich atmosphere, NASA has to take any hint of smoke or combustion seriously in order to ensure the safety of spacewalking astronauts.
Whitson and Tani recharged the water supplies for their EMUs while working aboard the space station Thursday. Two cooling system radiators were also deployed outside the space station. 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 nodeto its final perch at the front of the outpost's U.S.-built Destiny laboratory.
Also on Thursday, NASA approved plans 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, Madison said. The Italian-built Harmony node is designed to serve as the anchor for European and Japanese laboratories at the space station.
Commanded by veteran shuttle astronaut Stephen Frick, the seven STS-122 astronauts are slated to launch toward the space station aboard the Atlantis orbiter on Dec. 6, beginning an 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 spokesman Kyle Herring said.