On Friday, ESA astronaut Tim Peake and NASA astronaut Tim Kopra will exit the International Space Station (ISS) to carry out repairs to a faulty power unit. For Peake, it will be his first spacewalk – and the first Briton to venture out into space since dual U.S.-U.K. citizen Nick Patrick in 2010.
Peake, though, will be the the first solely British astronaut – and the first sponsored by the U.K. government and ESA (rather than NASA) – to perform an extra-vehicular activitty (EVA), or spacewalk.
The spacewalk will last around six hours, and the two Tims will work together to replace the defective components. “Our primary task will be to replace a failed Solar Shunt Unit, which transfers electrical power generated by the solar panels,” Tim Peake said in a statement.
“I am thrilled at this opportunity for a spacewalk. Right now we are focusing on preparing the tools, equipment and procedures.”
Final suit fit check prior to Friday's EVA – feels just great! #Principia #spacewalk @StationCDRKelly pic.twitter.com/JewRityiK4
— Tim Peake (@astro_timpeake) January 11, 2016
A spacewalk is an arduous task. First, the astronauts will breathe pure oxygen for two hours before donning the suits. By doing so, they expel nitrogen from their body, so when they wear the suits they don’t experience any negative physiological effects. The pressure inside the space suit is much lower than in the station and wearing them immediately would be similar to a scuba diver rising too quickly to the sea surface. The astronauts will wait in the airlock until the pressure is reduced, and it’s then safe to open the exterior hatch.
“Maintaining the International Space Station from the outside requires intense operations – not just from the crew, but also from our ground support teams who are striving to make this spacewalk as safe and efficient as possible,” added Peake.
The two astronauts have to be assisted when getting in and out of the suit. Scott Kelly, commander of the ISS, will help them with this task, as well as coordinating the repairs from the inside.
The repair itself should be simple enough, as replacing the Solar Shunt Unit is a relatively straightforward operation. The box can be removed by undoing a single bolt. Afterwards, the astrsonauts will lay cables for new docking ports and reinstall a valve that was removed last year.
The ISS has eight Solar Shunt Units, and the one which needs fixing broke last November. “If the spacewalk is successful, this will restore the International Space Station to 100 percent of its operational capability,” said Tim.