Astronauts take 2nd spacewalk to replace space station tank, 40 years after Apollo 13 launch

Astronauts take 2nd spacewalk to replace tank

CAPE CANAVERAL, Fla. — Astronauts struggled with stiff bolts while attaching a big new tank full of ammonia coolant to the International Space Station on Sunday, their second spacewalk in three days to accomplish the job.

The 215-mile-high action unfolded on the 40th anniversary of the launch of Apollo 13.

Spacewalkers Rick Mastracchio and Clayton Anderson called out directions as a robot arm lifted the 1,700-pound, refrigerator-size storage tank into place. One of the robotic snares got caught on the handling pin for the tank, but quickly was freed.

Then Mastracchio and Anderson had trouble bolting down the new tank on the sprawling framework that serves as the backbone of the space station. They tried using a pry bar on the mechanisms, but that didn’t work and Anderson retreated to the air lock to get more tools.

“Push, push, push, push, push. A little more,” one of the spacewalkers said as they tried to force the bolts.

“You guys want to take a breather for a minute?” shuttle commander Alan Poindexter asked from inside. “You guys just take it easy, relax your hands.”

The astronauts advised Mission Control to start coming up with a long-term solution in case the bolts would not cooperate.

The slot for the tank was emptied earlier in the spacewalk, when Mastracchio and Anderson popped out a nearly empty ammonia tank that had been on the space station for eight years. The ammonia is circulated through radiators to cool space station electronics.

Removing the old tank also had its share of difficulty. One side of the boxy container got hung up on a mechanism, and Anderson had to tug it loose.

“I’m really getting good at this,” Anderson said as the tank popped out. He had to use a pry bar during Friday’s spacewalk to get the new replacement tank out of space shuttle Discovery.

As the spacewalkers were moving the old tank toward the robot arm for capture, Anderson got caught on a pit pin and lanyard. “Jiminy Christmas,” he grumbled, freeing himself.

“Just go slow. It’s fine. There’s no rush,” astronaut Dorothy Metcalf-Lindenburger assured him from inside.

With the spacewalkers serving as lookouts, the robot arm placed the old tank on a space station rail cart for temporary storage. “Keep it coming … beautiful,” Anderson said. The men strapped the tank down with several tethers.

During the third and final spacewalk of the mission Tuesday, the tank will be placed into the shuttle for return to Earth. NASA plans to refill the ammonia tank and fly it back to the space station this summer as a spare. That will be the next-to-last shuttle flight.

As Mastracchio and Anderson worked outside Sunday morning, their colleagues unloaded more supplies out of the cargo carrier delivered by Discovery last week and stuffed it with old equipment and trash.

Discovery will remain at the space station until Saturday. Landing is scheduled for April 19.

Apollo 13’s three-man crew blasted off April 11, 1970. An oxygen tank ruptured two days later as the astronauts were en route to the moon. It became one of the most dramatic rescues ever seen by the world, and remains one of NASA’s shining moments.

On the Net:

NASA: www.nasa.gov/mission_pages/shuttle/main/index.html