In this image taken on Nov. 7, 2012, NASA astronaut Reid Wiseman and European Space Agency astronaut Alexander Gerst (partially obscured), both Expedition 40/41 flight engineers, attired in training versions of their Extravehicular Mobility Unit (EMU) spacesuits, are submerged in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Divers (out of frame) are in the water to assist Wiseman and Gerst in their rehearsal, which is intended to help prepare them for work on the exterior of the International Space Station.
The NASA astronaut was out on a spacewalk with crew member Steve Swanson to replace a backup computer box on the International Space Station when he decided to take a photo.
"The space suit makes it very difficult to get a good selfie. I tried several today," Mastracchio said of the photo.