A pair of astronauts are slated to venture outside the International Space Station on Tuesday morning to conduct an emergency spacewalk to replace a broken computer, one of two computers used to run all the U.S. systems aboard the $100 billion orbiting laboratory.
The astronauts, Peggy Whitson and Jack Fischer, will be conducting the spacewalk to fix the multiplexer-demultiplexer, one of two data relay boxes used to control the solar array systems, radiators, cooling loops and other hardware aboard the station. While the backup computer is functioning just fine, according to the official NASA release, the astronauts still aren't wasting any time in getting the replacement installed.
Whitson, the astronaut who just broke the American spaceflight record last month when she clocked more than 534 days in space, is arguably a sensible choice to oversee putting in the computer since she was part of the team that installed the now broken one back in March. To get ready to swap out the broken one, Whitson put together and tested a spare data relay box on Sunday.
The pair will suit up and step out into the void at 7 a.m., and will be out there replacing the data relay box for about two hours. Then, NASA officials have asked Fischer to install a pair of wireless communication antennas while Whitson finishes installing the box.
NASA officials have been careful to note that this is a routine spacewalk, but it's worth keeping in mind that even "routine spacewalks" are pretty rare.
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SHOW ME HOW
Spacewalks are not without risks. Back in 2013, astronaut Luca Parmitano nearly drowned during a spacewalk when his helmet started to fill with water. NASA officials decided to end the spacewalk early and when Parmitano got back inside the ISS, he had about two cups of water in his suit. That might not sound like much, but if things had gotten worse, the man might have drowned right there in nothing more than a puddle of water. Astronauts haven't gone on a spacewalk since December 2015, when a pair of them went out to release the brakes of a robotic arm that had seized up.
Every time an astronaut dons a spacesuit and steps out of the ISS, there's a chance that something could go wrong. Micro-meteors, shards of metal as small as granules of sugar, can puncture a spacesuit and cause a catastrophic leak. If the astronaut is in too much of a hurry putting on the suit, the rapid change in air pressure can cause nitrogen bubbles to expand in the blood vessels, giving the astronaut the bends. Spacewalks are also just physically challenging because it gets really hot in those spacesuits, even though they come with their own temperature regulation systems.
However, because of all the risks, astronauts have to train a ton before they get anywhere near actually working outside the ISS. Meanwhile, the spacesuits are tethered to the ISS. And even if one of the suits were to become disconnected from the space station, the outfits are equipped with small jet packs that would allow the astronauts to float back to the station instead of, you know, not doing that.
This will be the tenth time Whitson has ventured outside of the ISS, but only the second time Fischer has been tapped for a spacewalk. Fingers crossed that the whole endeavor goes so smoothly we'll barely remember it even happened.