Astronauts Rick Mastracchio and Clay Anderson went outside their home in space this morning to install a new cooling system and to perform several house keeping chores 220 miles above earth.
This second of three planned spacewalks began 45 minutes earlier than planned. It is expected to last 6 1/2-hours.
The second spacewalk of shuttle Discovery's ten day's of docked operations at the International Space Station began today at 1:30 am EDT, as the complex flew 219 miles above Australia and toward.
Six minutes later, the orbital duo left the American Quest airlock to begin the installation of a new ammonia tank assembly on the starboard truss segment. This is the 142nd spacewalk to assemble and maintain the station.
Thirty minutes into the EVA -- NASA-speak for spacewalk -- Anderson disconnected several electrical lines between the station the the old ammonia tank.
Mastracchio then began loosening the four bolts -- counter clockwise sixteen turns each -- which are holding the aging tank in place.
The old ammonia tank, which weighs 1295 pounds here on earth, will be exchanged with a new tank which weighs 1700 pounds.