Anhydrous Ammonia Tank
STS-131 Mission Specialist Rick Mastracchio exits the Quest airlock on the International Space Station on April 9, 2010 to begin the first of three spacewalks.
(Image: © NASA TV)
Two astronauts floated outside the International Space Station early Friday to begin the tricky task of replacing a large, old ammonia tank on the orbiting laboratory’s hull.
Discovery shuttle astronauts Rick Mastracchio and Clayton Anderson had to use a prybar to pull the new ammonia tank off its mooring in Discovery’s payload bay after it got stuck. But after that, its move to a temporary storage point on the station went smoothly.
“Clay, you did a great job holding that tank steady," the astronauts said.
The space walkers spent 6 1/2 hours working outside the station to disconnect an empty ammonia tank on the station and prepare its replacement for installation on a later spacewalk. It was the first of three spacewalks planned for their mission.
“Great job” Mastracchio said of the orbital work.
The1,700-pound (771-kg) ammonia tanks are large boxy units filed with toxic coolant for the space station’s thermal control system. The old tank thespacewalkers are replacing is empty, and will be returned to Earth on Discoveryto be refurbished and refilled.
Andersonis especially qualified to man-handle the space station?s ammonia tanks.
Afterall, he tossed a different one off the station in 2007 to discard it while on asix-month mission on the orbiting laboratory. The tank stayed in orbit as spacejunk for more than a year before burning up in Earth’s atmosphere.