The crew of the Mir space station struggled yesterday to get the ship's computer working and regain full control of the ailing craft, but ground controllers said it could take days to sort out the problem.
Ground control said the crew spotted and replaced a faulty part in the computer and began reloading information to make it operate. Further tests would then be needed to see if the computer was working normally.
After that, the crew will have to spend at least one more day switching on the gyroscopes that adjust Mir's position so that its solar panels get maximum energy from the sun.
Space officials insisted the crew was in no danger.
"The crew is expected to spend most of today checking and fixing the problem with their on-board computer . . . Restoring the Mir's orientation will take two or three days," said spokesman, Mr Valery Lyndin.
Mr Lyndin would not comment on what exactly went wrong in the computer.
Although Mir was hit by a similar problem in July, mission control said it would take longer to restore the computer this time because the cause of the latest shutdown was not immediately clear. The computer shut off in July when one of the crew accidentally unplugged a vital cord.
The computer problem means there will be delays before the crew can begin trying to fix damage from a June collision with a cargo ship.
"The walkout into the Spektr module will certainly be delayed as they have to adjust the station before doing that," Mr Lyndin said.
The latest mishap to the orbiting station came on Monday when the computer failed shortly before a docking with a cargo ship. The failure left Mir unable to maintain the position needed to recharge its solar batteries.
Asked how the two Russian cosmonauts and the US astronaut, Mr Michael Foale, were faring during the crisis, the chief of Russian Mission Control, Mr Vladimir Solovyov, said: "Well, they're trained to deal with such consequences."
Given its size, the station has enough oxygen for several days, and the crew has many weeks' supply of oxygen "candles", which generate oxygen when burned.
The computer failure occurred four minutes before the scheduled docking of a Progress cargo ship. When the breakdown became apparent, Mission Control ordered Mir commander, Mr Anatoly Solovyov, to switch off the automatic docking system.
"The commander of the crew immediately took charge and started manual operations," said the Mission Control chief, no relation to the station's commander of the same name. The docking went smoothly, he said.
The crew had been scheduled yesterday to begin fixing the damage caused by a collision with an earlier Progress cargo ship. The last crew was practising manual docking in June when the cargo ship veered out of control and crashed into one of Mir's six modules, piercing it.