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

JSC2011-E-029127 (25 March 2011) --- NASA astronauts Michael Fincke and Greg Chamitoff (partially obscured), both STS-134 mission specialists, attired in training versions of their Extravehicular Mobility Unit (EMU) spacesuits, are submerged in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Divers (out of frame) are in the water to assist Fincke and Chamitoff in their rehearsal, which is intended to help prepare them for work on the exterior of the International Space Station. Photo credit: NASA or National Aeronautics and Space Administration