Space shuttle Discovery's engines ignited at 6:21 a.m. EDT Monday, April 5, for liftoff of the STS-131 mission from Launch Pad 39A at NASA's Kennedy Space Center. 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, 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.