--Photo courtesy of NASA.gov.
As much of America sleeps, two astronauts on the International Space Station will – in the words of a NASA official -- go out the door on Dec. 21 and replace a broken cooling pump.
Three space walks may be needed to replace a pump module, NASA scientists said during a press conference Dec. 18. Astronauts Rick Mastracchio and Mike Hopkins will tackle the job, set for 7:10 a.m.
Mastracchio has been “out the door” before, with six space walks under his belt. Hopkins is a rookie. Adding drama to the mission, Hopkins will wear the suit worn by Luca Parmitano, an Italian astronaut who nearly drowned when his helmet unexpectedly filled with water during a spacewalk in July. Water went into Parmitano’s ear cups, covered his nose and nearly reached his eyes, according to reports.
Scientists referred to the incident as a “suit anomaly.” But Parmitano's ill-fated spacewalk, which ended abruptly, clearly clouds the repair mission. Components of the suit have been changed. NASA officials said they feel confident it is clean and ready to go. But just in case, they are ready with a rigged solution.
The astronauts will wear an absorbent pad in the back of their helmets in the event of another leak. Engineers also figured out a way to take plastic tubing and, strapping it together with Velcro, craft a makeshift snorkel, just in case.
NASA reported the pump problem Dec. 11. A flow control valve in the starboard pump module, which enables ammonia to cool station systems, stopped working properly, creating a temperature drop in one of the two external cooling loops. The loops circulate ammonia outside the station to keep both internal and external equipment cool, according to NASA. Engineers attempted to fix the problem from the ground but were unable.
The station’s crew was never in danger, but the problems have affected the team’s ability to do scientific experiments, said Dina Contella, space station flight director.
Midway through the press conference, a reporter asked about the worst-case scenario: If the other cooling loop also stopped working, would the astronauts have to abandon the station?
In so many words, the answer was yes.
“If you are down a cooling system and you lose the other cooling system, then we run into quite a few challenges,” said Mike Suffredini, NASA's space station program manager. “We’d have to rely on the Russian segment [of the station], and we’d be in a pretty big hurry to try to get outside and repair it. That would challenge us if we had both loops down. We’ve always known that was a big concern, and so we try not to leave ourselves in that posture. … It doesn’t do us a whole lot of good to evacuate the space station if we lose the coolant systems. It does us a lot more good to stay there and fix it so we can get on with things.”
The second spacewalk is set for Dec. 23. A third could be necessary Christmas Day. NASA postponed the upcoming Orbital Sciences Corp.'s commercial cargo resupply mission to proceed with the spacewalks. Orbital Sciences' Cygnus spacecraft, atop its Antares rocket, now will launch no earlier than January.
Contact: jhennessy@yttwebzine.com
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