Two Tims booked for January spacewalk

On 15th January, we will be watching "A Tale of Two Tims" as ESA's Tim Peake and NASA's Tim Kopra will both be heading out of the airlock of the International Space Station (ISS) to perform a spacewalk.

Major Tim Peake during spacewalk training back on Earth
Major Tim Peake during spacewalk training back on Earth
Credit: ESA/NASA

Their mission will be to replace a broken Solar Shunt Unit, a simple-looking box which transfers the electrical power generated by the external Solar Arrays back to the ISS. There are 8 of them in total, but the station has been operating with just 7 of them since November. The walk will last around 6 hours in order to complete this task, and should be relatively straightforward... Or as much as it can be inside a giant suit and floating around in Outer Space! Once done, the two Tims will install some cables to prepare new docking ports that will allow the station to receive different kinds of vessels, and they will also reinstall a valve that was removed when the Leonardo Permanent Multipurpose Module was relocated last year.

The Solar Array
The Solar Array was visible behind NASA astronaut
Scott Kelly as he carried out the previous spacewalk
on 21st December 2015.
Credit: ESA/NASA

"I am thrilled at this opportunity for a spacewalk," Peake told ESA in a statement. "Right now we are focusing on preparing the tools, equipment and procedures. 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."

Preparations for a spacewalk take almost an entire day. Not only does it take a long time to get each astronaut into their custom-made spacesuits, but they must also sit in a decompression chamber for a few hours to avoid getting the "bends" (nitrogen bubbles in the blood - scuba divers must carry out a similar procedure), and then breathe in pure oxygen for a full hour before exiting the station. Add this to the 6-hour long mission, plus another visit to the chamber on the way back in, and I think it's safe to say that the astronauts will have earned their sleep that night!