NASA

NASA astronaut Barry "Butch" Wilmore took a selfie over the weekend as he took part in the first of three spacewalks outside the International Space Station. The walk, which Wilmore completed alongside fellow astronaut Terry Virts, is part of an effort to prepare the station for future arrivals by a U.S. commercial crew space craft.

As the station orbited about 220 miles above Earth, Wilmore shot a selfie which shows an upside-down Virts reflected in his visor. The Earth, appearing blue with swirls of white clouds, looms in the background. Virts shared the selfie on Twitter.

The spacewalks are designed to lay cables along the forward end of the U.S. segment to bring power and communication to two International Docking Adapters slated to arrive later this year. The new docking ports will accept U.S. commercial spacecraft launching from Florida beginning in 2017, permitting the standard station crew size to grow from six to seven and potentially double the amount of crew time devoted to research.

The second and third spacewalks are planned for Wednesday and Sunday, with Wilmore and Virts participating in all three.