HOUSTON – Restoration of a failed computer system returned life to a regular rhythm on the international space station Sunday, as two astronauts completed the fourth spacewalk since space shuttle Atlantis docked with the outpost a week ago.
"We're slowly moving back into a normal mode of operations," station commander Fyodor Yurchikhin radioed Mission Control in Moscow.
The "normal mode" included the last spacewalk of the mission, a previously unscheduled fourth trip outside the space station that finished up tasks originally scheduled for last Friday's third spacewalk. Astronauts on the third spacewalk had the unplanned job of repairing a thermal blanket, which had peeled back near Atlantis' tail during the June 8 launch.
The nearly 6 1/2-hour spacewalk ended with astronauts Patrick Forrester and Steven Swanson completing nearly all of their tasks.
They 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 United States and Russian sides of the space station. They were not able to bolt down a problematic debris shield and instead secured it in place with tethers.
At the end of the day, flight controllers on the ground planned to give the rotating joint a small test by moving it 5 degrees. A more thorough test to see whether the solar arrays track the sun was in store on Monday.
Flight controllers on Monday planned to test the space station's thrusters, which haven't been used since the crash last week of the Russian computers, which control orientation and oxygen production.
Yurchikhin and Russian cosmonaut Oleg Kotov got four of the six computer processors operating again on Friday. The remaining two were brought back online on Saturday but then flipped back off to be "in cold standby mode" so that they could be used if needed.
"We can report that things are still improving," said flight director Holly Ridings.
With the exception of an oxygen generator, all of the space station systems that were powered down when the computers failed were back running.
Mission managers will decide after the station's thrusters are put to the test whether Atlantis needs to spend another day at the outpost. During the computer meltdown, Atlantis' thrusters were used to help the station maintain its orientation.
Atlantis is set to undock on Tuesday and land Thursday in Cape Canaveral, Fla.
"We're going to give it a checkout," Ridings said. "We'll make sure the computers are still talking to the thrusters and prove to ourselves that we've got everything we need in order to undock safely."
While the seven-member crew of Atlantis and the three-man crew of the space station spent Father's Day 220 miles above Earth, the holiday didn't slip the minds of the nine fathers at the outpost who collectively have 24 children.
"Happy Father's Day to everybody downstairs," said U.S. astronaut Clay Anderson.