CAPE CANAVERAL, Fla. — A pair of spacewalking astronauts disconnected an empty ammonia tank outside the International Space Station yesterday and got a new one ready to put in its place.
In the first of three spacewalks needed to complete the job, Clayton Anderson had no problem taking apart the ammonia lines on the old tank. But he needed a pry bar to remove the new tank from space shuttle Discovery’s payload bay. The tank got hung up on a bolt.
“Go nice and easy, Clay,’’ spacewalking partner Rick Mastracchio warned as Anderson pushed and prodded with the pry bar. After several tries, the tank finally came free. “We got it!’’ Anderson called out.
The two men lifted the 1,700-pound tank out of Discovery and handed it off to a robot arm, which maneuvered it to a storage location at the space station.
The actual swap-out of the two tanks will take place during the second spacewalk tomorrow, with the entire effort wrapping up after the third and final outing Tuesday.
There were a few tense moments early in yesterday’s spacewalk when Mastracchio reported that he bumped a large, V-shaped bar in the shuttle payload bay and it was sliding around. Mission Control later said its engineers were “pretty convinced’’ it was normal for the clamp to move around a bit, but as a precaution, the spacewalkers were warned to stay away from it.