The destruction date for the Mir space station is still not set.

A Russian expert quoted by the Itar-Tass news agency says the exact date for the scuttling operation remains uncertain but is likely to be after 8 March.

Nikolay Ivanov, a ballistics expert at Moscow's mission control centre, called 8 March a "key point" at which Mir would be 250 kilometres above the Earth.

"Just then, regarding the condition of the atmosphere, we shall decide when to give momentum for the station's descent," he said.

He said "natural momentum" was now lowering orbital height of the platform by an average 750 metres a day.

Ground specialists are checking the operation of Mir's equipment. The main task is to economise on fuel so the station has enough when the de-orbit command comes from controllers, Ivanov said.

Until now, the Russians have mentioned 6 March as the planned destruction date. The platform, which weighs in excess of 130 tonnes, will disintegrate and burn up as it tumbles through the thicker layers of the Earth's atmosphere.

Large chunks are expected to make it through to the surface of the planet, but Russian space officials hope to time the whole procedure so that any debris hits a remote area of the southern Pacific.