Reports & Cadet Blog
MESSAGE 23: “WALKING” AROUND IN SPACE ON OCTOBER 20
One of the most exciting tasks performed on the ISS is a spacewalk, or extra-vehicular activity (EVA). This is when astronauts step out into space to conduct critical missions that the station’s two robotic telemanipulator units cannot. Two astronauts on Expedition 53’s crew (the current team manning the station), our very own Randy Bresnik, commander, and Joe Acaba, flight engineer, will be conducting their third and final spacewalk related to this project on Friday, Oct. 20, 2017. (Photos in the post courtesy of NASA).
Their mission is to replace a fuse on a Dextre platform (one of two robotic units that conduct repairs outside the ship), set up an HD camera outside the station, prepare two units for robotic repair by removing their thermal insulation, and replace a light on the other robotic arm unit, Canadarm2’s latching system.
Preparing for a spacewalk is an extremely involved process that requires days of preparation. Besides preparing for whatever that particular spacewalk’s mission tasks are (whatever components have to be repaired, replaced, removed, etc.), astronauts need to prepare their bodies for the harsh conditions of open space. About an hour before their mission, they need to pre-breathe pure oxygen to eliminate nitrogen dissolved in their blood, which would otherwise be released as deadly bubbles when the pressure is reduced. The astronauts then hop inside the station’s airlock as it slowly decompresses from about 101 to 70.3 kilopascals (from the pressure felt on Earth at sea level to 69% of that pressure) until they can exit the station safely. Besides providing the required pressure (57.2 kilopascals – a little over half of the pressure on Earth at sea level) and oxygen, spacesuits protect astronauts from micrometeoroids and the extreme temperatures of space, which range from -250 degrees Fahrenheit in darkness to 250 degrees Fahrenheit when exposed to the sun’s rays directly.
This entire process will be livestreamed starting two hours before the actual spacewalk. Check it out Friday on NASA TV starting at 6:30 a.m. EDT.
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