Atlantis Astronauts Pack Up Shuttle for Trip Home

This story was updated at 7:53 a.m. EDT.

Astronauts on the space shuttle Atlantis packed up their spacecraft Saturday to get ready for their trip home and will get some well-deserved time off after a busy week of space station construction.

The six-man Atlantis crew has spent the last week at the International Space Station, where they added a new Russian room packed with supplies, fresh solar array batteries and a spare communications antenna.

They wrapped up their third and last spacewalk on Friday. So Mission Control planned to give the spaceflyers a few hours off today to rest up.

"I think we won't need to encourage them to rest up and it's about time," station flight director Emily Nelson said. Atlantis is due to undock from the space station Sunday and land in Florida on Wednesday morning.

During their 12-day mission, Atlantis astronauts installed the $200 million Russian research module Rassvet ("Dawn" in Russian), a new room that can also serve as a docking port for Russian spacecraft.

The Rassvet module is packed with a ton of U.S. supplies, but the station's own six-person crew won't be unload it until some metal shavings floating around inside are swept up by its air filters. Until the air is clear, the door to the station's new room will stay closed.

NASA station managers said it's not uncommon for new modules to have debris, and even metal shavings from its manufacture, floating inside. The Rassvet module's fans and air filters should clean up the interior just fine, they added.

Today, Atlantis astronauts used the space station's robotic arm to pack a huge cargo carrier laden with the old solar array batteries their replaced back inside the shuttle's cargo bay. They'll also pack up gear inside Atlantis that was used while working at the space station.

"So it?s a busy game of accounting for all of this equipment, making sure it goes to the right place and then getting the down mass down from space station," Atlantis commander Ken Ham said in a NASA interview. "Down mass is a growing concern with shuttle going away. You can?t bring it down on a Proton and a Soyuz is pretty small, so there?s a desire to get a lot of stuff back."

NASA plans to retire its three space shuttles this year to make way for technology and vehicle development for more ambitious missions to an asteroid or Mars. Atlantis' mission, STS-132, is expected to be the 32nd and last flight of Atlantis since it entered service in 1985. The shuttle launched on May 14.

After this flight, just two more shuttle missions remain, on Discovery and Endeavour, respectively.

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SPACE.com is providing complete coverage of Atlantis' STS-132 mission to the International Space Station with Senior Writer Clara Moskowitz and Managing Editor Tariq Malik based in New York. Click here for shuttle mission updates and a link to NASA TV.