``A new orientation and docking management computer has been installed, successfully tested and it is now controlling the station,'' a duty officer at Mission Control outside Moscow said.

``This device will keep the station in orbit when there is no one on board,'' he added.

The three-man crew aboard Mir is due to return to earth on August 28, leaving the station unmanned while space officials conduct a final desperate effort to find private or foreign funds to keep it flying. The government has said it can no longer afford to pay.

The new computer -- which will seek to keep the station from crashing down to earth prematurely -- was started ahead of schedule after the crew decided to take advantage of a power cut caused by a breakdown in Mir's main computer on Friday, he said.

Installing the computer requires disconnecting the power supply.

The crew has also used the occasion to install some other equipment which will allow the station to function automatically.

The new computer will be able to keep Mir's electricity-generating solar panels pointed towards the sun even if the main computer, which controls gyroscopic devices responsible for the station's orientation, fails.

Russia has said it might send up a new crew to the 14-year-old station if it finds more funds for the programme -- but so far they have failed to raise significant sums.

Deputy Prime Minister Ilya Klebanov said last month that Mir had fulfilled its goals and should be abandoned gracefully.

The United States wants Russia to abandon Mir to focus its resources on the International Space Station, which is scheduled to receive its first crew next year after considerable delays, mainly because of slow Russian construction of the living quarters.