How can astronauts replace the stations ammonia pump?
Spacewalking astronauts will replace the station’s stricken ammonia pump in two stages. During a Saturday, Aug. 7 spacewalk, they will physically remove the big faulty pump module and then bolt down a spare pump module in its place. One astronaut (Wheelock) will ride the space station’s robotic arm, while the other (Caldwell Dyson) will be floating free and tethered to the station’s truss structure. Their main worksite is on the station’s Starboard 1 (S1) truss segment, which is where the faulty pump is located. The spare pump is on a storage platform about 30 feet (9 meters) away. During the second spacewalk, the astronauts are expected to hook up the ammonia plumping and electrical lines to fully activate the new pump. There are five electrical connections and five liquid ammonia connections to be made. The astronauts must be careful when handling liquid ammonia plumbing lines in order to avoid any residual liquid ammonia which can contaminate their spacesuits and require extra decon
