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Space Station's Computers Seem A-OK

A revived set of crucial computers aboard the international space station appeared to pass one more test Monday, making it likely that space shuttle Atlantis will return home later this week.

The test was to determine if two Russian computers were ready to control the space station's orientation as Atlantis managers decide whether the shuttle should spend another day at the outpost.

"Everything so far looks good," said NASA spokeswoman Lynnette Madison. "Now managers are going to look over everything."

Officials were to decide later Monday whether everything was working properly.

The test began after the shuttle's rocket thrusters were used to re-orient the station for a shuttle waste water dump, reports CBS News space consultant Bill Harwood. When the excess water had been dumped overboard, flight controllers maneuvered the station back to its original orientation, or "attitude," and switched control over to the revived Russian guidance, navigation and control computers. The computers then commanded Russian thrusters to maintain the proper attitude for about an hour.

Control of the Russian thruster system then was switched to U.S. computers and again, the hardware and software worked together as required during the latter stages of the test to keep the station stable and pointed in the right direction. The results of the checkout operation will be reviewed by NASA's Mission Management Team later Monday. Barring additional problems, the Atlantis astronauts are expected to be cleared to seal hatches between the spacecraft Monday evening to set the stage for undocking on Tuesday.

During a computer meltdown last week, the shuttle's thrusters were used to help the station maintain its position. The station's thrusters haven't been used since.

"That's a big step in our checkout of the computers to make sure everything is working correctly," flight director Holly Ridings said Monday. "It's one of those things we want to see before we undock."

Atlantis is set to land Thursday in Cape Canaveral, Fla. The shuttle has been at the space station since June 10.

The computers, which also control oxygen production, crashed last week. All six of the computers' processors were back online Saturday. The two processors that took longer to revive are now on standby mode and can be used if needed.

Except for an oxygen generator, all the space station systems that were powered down when the computers failed are now running.

Also Monday, Atlantis' crew finished packing the shuttle for its return trip to Earth. The shuttle and space station crews were set to say their goodbyes before hatches between Atlantis and the outpost are closed in preparation for Tuesday's undocking. They were given some free time Monday morning to enjoy the view on their last full day in space.

On Sunday, shuttle astronauts completed the fourth and final spacewalk of their mission to continue the construction of the space station.

During a nearly 6½-hour spacewalk, astronauts Patrick Forrester and Steven Swanson activated a rotating joint — their top priority — on the outpost's newest segment so a new pair of solar wings can track the sun and provide power to the station. The solar arrays were delivered to the space station by Atlantis.

The astronauts also set up a new camera stanchion outside the station's newest segment and a computer network cable between the U.S. and Russian sides of the outpost. They were not able to bolt down a problematic debris shield and instead secured it in place.

Early Monday, flight controllers successfully gave the rotating joint a small test by moving it 5 degrees. During a more thorough test later in the morning, the joint began rotating automatically, allowing the solar arrays to track and sun and provide power to the station.

"The checkout went really well last night," Mission Control told the astronauts Monday morning.

U.S. astronaut Sunita Williams spent her last full day at the station showing the ropes to her replacement at the space station, U.S. astronaut Clay Anderson. She thanked flight controllers on the ground for their work during her more than six months in space in which she set a record for the longest single space flight by a woman.

"I'm sad to say goodbye but that means progress is being made and it's time for the international space station to grow a little more," said Williams, her voice cracking with emotion. "The (space station) will always be a part of me."

CBS News Space Consultant William Harwood has covered America's space program full time for nearly 20 years, focusing on space shuttle operations, planetary exploration and astronomy. Based at the Kennedy Space Center in Florida, Harwood provides up-to-the-minute space reports for CBS News and regularly contributes to Spaceflight Now and The Washington Post.
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