Dave Williams underwater at NBL during STS-118 EVA Training

JSC2007-E-26262 (4 April 2007) --- Astronaut Dafydd R. (Dave) Williams, STS-118 mission specialist representing the Canadian Space Agency, wearing a training version of the Extravehicular Mobility Unit (EMU) spacesuit, participates in an underwater simulation of extravehicular activity (EVA) in the Neutral Buoyancy Laboratory (NBL) near Johnson Space Center. SCUBA-equipped divers are in the water to assist Williams in his rehearsal, intended to help prepare him for work on the exterior of the International Space Station.