May 10, 2013
NASA May Have Expedition 35 Crew Conduct Spacewalk To Fix Ammonia Leak
Lawrence LeBlond for redOrbit.com - Your Universe Online
NASA said in an updated statement this morning that Expedition 35 crew will begin preparing for a potential spacewalk on Saturday to troubleshoot and possibly fix the ammonia leak discovered yesterday. A final decision on an external mission of the Space Station is not expected until later tonight, however.
NASA has reiterated that the crew is in no danger from the leak and the orbiting lab continues to operate normally. Engineers are continuing to work to reroute power channels in order to maintain full operation of electrical systems.
The spacewalk, if it is ordered, will be conducted by Chris Cassidy and Tom Marshburn, as they inspect the area where the leak is coming from, hoping to make repairs to the coolant system. Station managers are meeting this morning and will meet again later to discuss procedures and timeline for the spacewalk, if it is approved.
Cassidy and Marshburn have each conducted three spacewalks before, all on the STS-127 mission in 2009.
Main Story (May 10 @ 8:40 a.m.)
An ammonia leak has been found in the external cooling system on the International Space Station (ISS), according to NASA. The leak was discovered by Expedition 35 crew members on Thursday at about 10:30 a.m. CDT, after they reported seeing white flakes floating away from the station´s P6 truss structure.
Using a handheld camera, the crew documented the leak for Mission Control, which also filmed the malfunction with external television cameras to try to narrow down the exact location of the leak. The reports from the crew, along with the additional imagery by Mission Control in Houston, helped in confirming that the ammonia leakage rate was increasing.
The ammonia is used to cool the station´s electrical power systems. This leak is occurring in the same region as the one that the astronauts tried to troubleshoot during a November 1, 2012 spacewalk. It is not yet known if this ammonia outflow is from the same leak as the earlier problem.
The station is continuing to operate normally and Mission Control said in a statement that the crew aboard the ISS is in no danger. But in case there was an issue, the station has enough escape ships for the entire six-man crew to depart the orbiting lab.
According to FOX News, NASA spokesman Bob Jacobs said engineers are working to reroute electronics just in case the loop shuts down. Plans are also being developed to reroute other power channels as well to maintain full operation of onboard electrical systems. An early analysis of the leak rate indicates that the cooling loop could shut down in as little as 48 hours. Mission Control said further imagery may be needed to isolate the location of the leak.
Commander Chris Hadfield, who is scheduled to depart the station on Monday at 7:08 p.m. EDT along with NASA´s Tom Marshburn and Russian cosmonaut Roman Romanenko, asked Mission Control if the leak will affect undocking.
Capsule Communicator Doug Wheelock explained that Mission Control officials didn´t see anything that could not be overcome technically, and they would have more information on Friday, indicating the leak should not be a problem for undocking procedures.
According to the BBC, Hadfield, who has a cult following for his orbital photography, tweeted an image of Planet Earth before bedding down for the night on Thursday: "Tonight's Finale: A view to put the mind at ease."
When Hadfield, Marshburn and Romanenko leave the station on Monday, the three remaining members will become part of Expedition 36 under the command of Russian cosmonaut Pavel Vinogradov. Three new members will arrive on the station later this month.