STS-131 Mission Specialists Rick Mastracchio and Clay Anderson switched their spacesuits to battery power at 1:31 a.m. EDT, signaling the start of the mission’s first spacewalk 10 minutes ahead of schedule. Dottie Metcalf-Lindenburger is coordinating the activity from inside the International Space Station and communicating with Mission Control in Houston.
Mastracchio is EV1, wearing a red stripe on his suit, and Anderson is EV2, wearing a solid white suit.
The two spacewalkers will begin the task of changing out a depleted Ammonia Tank Assembly on the station’s starboard truss, a job they will continue during the second and third spacewalks on Sunday and Tuesday. They also will retrieve the Micro-Particles Capture/Space Environment Exposure Device (MPAC/SEED) experiment from the outside of the Japanese Exposed Facility for return to Earth and swap out a failed Rate Gyro Assembly, part of the station’s navigation system. The excursion is scheduled to last 6.5 hours.