Spacewalking astronauts tackle pump work at space station

NASA astronauts are taking a spacewalk to shuffle around a couple of space station pumps.

Drew Feustel (FOY-stull) and Ricky Arnold emerged from the International Space Station on Wednesday. They need to rearrange the space station's external cooling system by swapping the positions of two spare ammonia pumps.

NASA wants the best spare in the best spot. One pump got too cold because of a power shutdown 17 years ago and is called Frosty. The other spewed out ammonia five years ago and is dubbed Leaky.

Meanwhile, the station's six-man crew is expecting a delivery. Orbital ATK plans to launch a supply ship Sunday from Wallops Island, Virginia. Weather permitting, the pre-dawn flight of the Antares rocket should be visible along the East Coast from New England to South Carolina.