NASA is targeting Wednesday morning for a second spacewalk to remove a failed coolant pump outside the International Space Station.
A first try on Saturday that lasted over eight hours was unsuccessful because one of four fluid hoses was difficult to seal and leaked ammonia. The 780-pound pump module can't be removed before all four hoses are disconnected.
Before the second attempt by Doug Wheelock and Tracy Caldwell Dyson, ground controllers plan to reduce the coolant loop's pressure from about 370 pounds per square inch down to less than 200 psi. Teams will will close additional valves to stop the flow of ammonia through the pump module and "dry" the line by venting ammonia from it and the pump.
Today, veteran astronauts and spacewalkers Peggy Whitson and Rex Walheim are practicing the spacewalk's planned procedures in the Neutral Buoyancy Lab near Johnson Space Center, a giant swimming pool that holds a mockup of parts of the space station.
The spacewalk hopes to unhook the troublesome last ammonia line, then continue to detach five power and data cables and four bolts to remove the pump module and temporarily stow it. Then it will prepare a space for installation.
Depending how Wednesday's events go, a third spacewalk to complete the job is tentatively planned Sunday.
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Space news and analysis from Kennedy Space Center and Cape Canaveral 
2 comments:
Three spacewalks to fix one problem on ISS. Any more delays and we might have to lower that American pride and ask Russian cosmonauts to fix it.
Oh knock it off...this isn't changing the oil on a 1955 Buick!
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