The crew of Mir said they noticed "strange drops of brown colour" coming out of the engines of their Soyuz escape capsule soon after Mir's main computer crashed yesterday.
"We have another observation which we do not understand at all. When we were monitoring the turning of the ship we saw some brown drops coming from it," Russian Cmdr Anatoly Solovyov told mission control during a radio link-up.
Flight engineer, Pavel Vinogradov, added: "It happened after the engine's work. The drops were fanning outwards for a long time and then stopped. They were of brown colour."
Mr Vinogradov explained that the crew had to fire the Soyuz engines to turn the station, so its solar panels could soak up more energy. The automatic orientation system was switched off after the computer failure.
The main computer had broken down, forcing the crew to shut down all systems.
"Everything is shut off," Mr Solovyov said. Only vital life-support systems were left on, he said, adding that lights were switched off as well.
A Russian mission control spokeswoman said the reasons for the failure were not immediately known. The US-Russian crew were not in danger, she added.
Yesterday's failure was the fifth computer breakdown to jinx Mir since the worst accident in the station's 11-year history on June 25th, when a cargo tug collided with the station, slashing power supply and holing its Spektr scientific module.
The present Mir crew has fixed four computer failures in 47 days. NASA astronaut, Michael Foale, has been on Mir since May and is to leave this month.