It’s official: NASA astronauts will have to step out into space to fix a faulty cooling loop at the International Space Station. Rick Mastracchio and Michael Hopkins will take on the task, which will probably take two spacewalks and could stretch to three.
The spacewalks, scheduled for Dec. 21, 23 and 25, come after engineers at NASA’s Johnson Space Center in Houston tried fiddling with a broken valve in a pump in an ammonia cooling loop to figure out what exactly was wrong with it. The pump was shut down last week after it failed to regulate the ammonia levels and it got too cold, NASA officials said.
The space station has two such cooling loops, each of which help keep the flying facility from overheating (because it’s hard to get heat to properly dissipate in space, NASA officials said). Vital systems in the European and Japanese modules were moved over to the other cooling loop, but a few experiments were put off, according to a previous video interview with Mastracchio.
Rather than focus on fixing the valve, the astronauts will simply replace the entire pump – the International Space Station has three spares on board, said NASA spokesman Josh Byerly.
Each spacewalk will take several hours, and the astronauts will have to work deliberately, Byerly said.
"These pumps have ammonia in the lines so you got to be pretty careful with that," Byerly said in an interview. "Ammonia can be pretty irritating and that’s not really something we want to get on an astronaut."
The spacewalks would be the first for the United States since Italian astronaut Luca Parmitano nearly drowned in space this summer. The European Space Agency astronaut’s helmet began to fill with water while he floated outside the space station during a spacewalk this summer.
The suits have since been reexamined, Byerly said.
“They’re comfortable doing the spacewalk,” Byerly said. “They’ve done a lot of work on the spacesuit.”
The faulty cooling loop situation also delayed an unmanned resupply launch by Orbital Sciences Corp. to January, Byerly said.
[For the record, 5:31 p.m.: An earlier version of this story incorrectly stated that the spacewalks are scheduled for Dec. 23, 25 and 27. They are set for Dec. 21, 23 and 25.]