NASA TV
Rick Mastracchio (left) and Mike Hopkins check a U.S. spacesuit inside the Quest airlock.
The objective is to replace a pump with a bad valve, which stopped working on Dec. 11. The pump is associated with the station's cooling system - it circulates ammonia outside the station to keep equipment cool. However, because of the bad valve "one of two cooling lines became too cold," the AP said.
Spacewalks led by U.S. astronauts have been suspended since Italian astronaut Luca Parmitano almost drowned in July when his helmet filled with water.
But NASA has come with a surprisingly simple solution to this problem: a makeshift snorkel.
According to FoxNews, the astronauts whipped up the life-saving device this weekend, using materials on board:
"Some smart engineers on the ground said, hey, this looks like a snorkel you'd use for scuba diving," explained Allison Bolinger, NASA's lead U.S. spacewalk officer. NASA realized that a water-line vent tube could be snipped down and attached with Velcro within the spacesuit, between a water restraint valve and the astronaut, she explained.
The crew members themselves fabricated the snorkels on Sunday.
"This is your last resort … if water is in your suit you can lean down and use this to breathe," Bolinger said.
The space agency also installed absorptive pads in the back of each helmet, which will soak up any water that shows up like a sponge. The spacewalkers have been trained to tilt their heads back periodically to test the pad, she said; if it sucks up around 6 and a half ounces of water, it will feel "squishy" - a sure sign of trouble.
It's clear the astronauts have been hard at work. On Tuesday, veteran spacewalker Mastracchio tweeted this picture:
Have not looked out the window in 4 days. Too busy building space suits. Where did I put my gloves? pic.twitter.com/XDqcBKl9dG
- Rick Mastracchio (@AstroRM) December 17, 2013
The first spacewalk is planned for Saturday, the next on Monday, and if necessary, a third spacewalk could happen on Christmas day.
A resupply ship scheduled for this week has been put on hold until mid-January because the astronauts are so busy.