MOSCOW (AP) - The fourth computer breakdown in two months left a darkened Mir drifting through space Monday, less than two weeks before a scheduled docking with a U.S. space shuttle.
The Russian-American crew kept essential functions operating and was in no danger, officials said. But the shutdown provided new fodder for critics who fear the Russian station is unsafe after 11 years in space.
After a day of in-orbit tinkering, the Mission Control press service announced that everything should be back to normal on Mir within two days. The crew rummaged through the station's broken computers and found enough spare parts to assemble one functional system, which responded positively to tests late in the day.
Most of Mir's systems remained shut off in the wake of Sunday's breakdown, to conserve energy in case computer problems appear. The orientation systems and main oxygen generators were down and temperature controls and lights were switched off in all but two modules.
As well as making life difficult on Mir, a computer failure would make docking with the shuttle Atlantis or any other spaceship "absolutely impossible," deputy Mission Control chief Viktor Blagov.
But Blagov stressed his confidence in the crew's ability to rein in the cranky system.
"The situation does not exceed the limits of Russian standards," he said, hours before a jury-rigged computer was put in place.
The crew had replaced the main computer following the last breakdown, on Sept. 8, and thought they had taken care of their computer problems for a while. But Blagov said that difficulties earlier this year could have damaged the spare computer.
The computer had been in storage on Mir for more than two years in less than ideal conditions that included excessive humidity and a leak of coolant fluid, Blagov said.
On Sunday, the system turned itself off after two of its three blocks began acting up. The crew restarted the computer Monday and it appeared to be working normally, but Russian officials decided to replace the two blocks that had malfunctioned anyway.
Officials in charge of the cash-strapped Russian space program said they let the previous computer wear out before installing a new one. The Russians no longer replace parts when they reach the end of their life expectancy, they just keep them running until they expire.
"All these malfunctions can be traced to the years when the industry has had absolutely no money, and we have had to find ways to survive using spare parts and old techniques," Blagov said.
The two computer shutdowns in the past week have been less troublesome than previous ones in July and August, because the Mir is now running at closer to full power, space officials said.
The crew has a two-month supply of oxygen canisters, which are used when the oxygen-generating system goes down. The gyroscope system, which orients the Mir toward the sun, also was down. But the crew can fire thrusters to periodically reorient the station.
Both the Russians and Americans insist the station remains safe despite its string of breakdowns this year.
The Atlantis is scheduled to blast off Sept. 25 for a docking with the Mir. The space shuttle will ferry up thousands of pounds of supplies and repair gear, including sealant for holes in the fractured hull of the Spektr module. American astronaut David Wolf also will replace Michael Foale.
If Mir's computer fails while Atlantis is approaching, the space shuttle could orbit near the station until the malfunction is fixed.