STS-134 crew members Michael Fincke and Greg Chamitoff during their final EVA4 training run at the NBL.

JSC2011-E-029130 (25 March 2011) --- NASA astronaut Greg H. Johnson (foreground), STS-134 pilot, participates in a training session in the simulation control area in the Neutral Buoyancy Laboratory (NBL) at the Sonny Carter Training Facility near NASA's Johnson Space Center. Photo credit: NASA or National Aeronautics and Space Administration