The Znamya (banner) experiment is to be launched next February and envisages unfolding a space mirror made of a membrane covered by a metal layer. In theory, the mirror is to work like the Moon, reflecting sunlight onto some northern parts of Russia during the long nights.

The mirror, around 30 metres in diameter, would serve as a prototype for even larger models that may go up later, provided the cash-strapped space agency comes up with funds, said mission control spokesman Valery Lyndin yesterday.

``Of course, longer-term prospects are unclear, given the current fund shortage,'' Lyndin said in a telephone interview.

Russia also plans to discard the Mir next year, making further experiments with space mirror unlikely in the foreseeable future, he added. Lyndin also acknowledged that building larger mirrors ofseveral hundreds metres in diameter would be a much more complex technical task, because they would be much harder to unfold and maneuver in orbit.

According to the plan, the folded membrane is to be attached to a Progress cargo ship, which is scheduled to blast off for the Mir space station on Sunday and dock with it on Tuesday.

The Progress will unfold the mirror in February, when the cargo ship will be undocked from the Mir. Usually, it would be discarded. In this case, the station's crew will guide the cargo ship using manual controls for a while to see how the mirror performs.

Lyndin wouldn't say exactly how long the experiment would last. Eventually, the cargo ship would be allowed to burn in the atmosphere as usual. He said that ``the scientists will also study the membrane as a potential solar sail,'' a feature that might allow spaceships of the distant future to sail through space using solar wind.

In February 1993, Russia ran a similar experiment, but the mirror was barely visible on earth,Lyndin said. The new Znamya also would be visible only in good weather and to those who knew its precise position in orbit.