On April 11, 2010 American astronauts STS-131 Mission Specialists Richard Mastracchio and Clayton Anderson completed a seven-hour and 26-minute spacewalk.
In the NASA photo: astronaut Richard Mastracchio participates in the spacewalk.
Using a combination of robotics and spacewalking expertise, Discovery’s crew members installed a new Ammonia Tank Assembly (ATA) on the International Space Station’s Starboard 1 truss. Mission Control verified that electrical connections with the ATA are working. Because of a troublesome bolt, the spacewalkers fell behind the timeline and were unable to complete all the scheduled work.
This was the second of three STS-131 spacewalks, the 235th conducted by U.S. astronauts and the fifth for both Mastracchio and Anderson. It was the 142nd in support of International Space Station assembly and maintenance. It was the 114th spacewalk based out of the space station.