5 April 2010 --- After suiting up, the STS-131 crew members exit the Operations and Checkout Building to board the Astrovan, which will take them to launch pad 39A for the launch of space shuttle Discovery on the STS-131 mission. On the right (front to back) are NASA astronauts Alan Poindexter, commander; Rick Mastracchio, Stephanie Wilson and Clayton Anderson, all mission specialists. On the left (front to back) are NASA astronauts James P. Dutton Jr., pilot; Dorothy Metcalf-Lindenburger, and Japan Aerospace Exploration Agency (JAXA) astronaut Naoko Yamazaki, both mission specialists. Liftoff of the STS-131 mission is set for 6:21 a.m. (EDT) on April 5. On STS-131, the seven-member crew will deliver the multi-purpose logistics module Leonardo, filled with supplies, a new crew sleeping quarters and science racks that will be transferred to the International Space Station's laboratories. The crew also will switch out a gyroscope on the station's truss structure, install a spare ammonia storage tank and retrieve a Japanese experiment from the station's exterior. STS-131 is the 33rd shuttle mission to the station and the 131st shuttle mission overall.