Spacewalkers Danny Olivas and Christer Fuglesang have unbolted an ammonia tank with the mass of a small car from shuttle Discovery's payload bay. Strapped into the International Space Station's robotic arm, Fuglesang will hold the coolant tank as crewmates Kevin Ford and Nicole Stott steer the arm up to the Port 1 segment of the station's central truss.
Fastened to the opposite side of the arm's end is the old ammonia tank that Olivas and Stott removed from the truss Tuesday.
The new tank weighed 1,702 pounds at liftoff, including 600 pounds of ammonia. The old one was down to about one third of its ammonia supply and will weigh nearly 1,300 pounds on the ground.
"That's a pretty big object for a crew member to actually handle," station flight director Royce Renfrew said earlier today. "A lot of people think we're in zero-G, it doesn't weigh anything zero-G, and that's true -- you can take this 1,800-pound mass and just barely touch it and make it move. "But once it starts moving, you have to be able to stop that mass as well. There's a lot of physics involved in playing with large masses in space that humans beings are holding."
Holding the new tank, Fuglesang will ride a fairly long distance on the arm from the rear of Discovery's payload bay to the Port 1 truss. Olivas will have to hike there by hand.
The two spacewalkers will install the new tank with four bolts and connect fluid and electrical cables.
Then Olivas will grab the old tank from the arm, allow Fuglesang to reposition himself and then hand it back to Fuglesang for the ride back to the payload bay.
The old tank will be bolted to a carrier for the return to Earth. The tank will be refurbished for return to the station next March, this time on the starboard side.
Though today's spacewalk began nearly an hour behind schedule, Olivas and Fuglesang are said to be ahead of their timeline.
y
No comments:
Post a Comment