By BBC News Online Science Editor Dr David Whitehouse

The Russian Space Agency has announced that three cosmonauts will blast off for the currently unmanned Mir space station at the end of March - but whether they will be preparing Mir for its destruction later this year is not certain.

The crew may be preparing Mir for a visit by a further crew, or ensuring that it is destroyed in a controlled re-entry into the Pacific this year. It seems that when the crew blast-off they will not know which of these two options they will be carrying out!

The uncertainty stems from the obvious fact that Russia just does not want to get rid of Mir but does not have the money to keep it working. It promised the US that it would de-orbit Mir.

The US does not believe that Russia can work effectively on two space stations at once. It wants Russia to concentrate on the International Space Station (ISS) and abandon Mir.

Last year, Russia said that Mir would be de-orbited by the end of 1999, then early 2000 and now possibly in the autumn.

Russian pride

The fact is that Russia does not want to loose Mir because it is a potent symbol of the glory days of their space effort and their last independent major space project. The latest date for another "final" decision about Mir's fate is evidently due in April.

The Russian Space Agency says that the forthcoming cosmonaut flight to Mir has been partially financed by the venture finance company Gold and Appel. This company, based in the British Virgin Islands has already invested in American private space ventures.

It has been reported to have provided $20 million for the cosmonauts flight.

Before the cosmonauts depart in late March an unmanned progress spacecraft will be dispatched later this month to carry fuel and oxygen to Mir.

Viktor Blagov, deputy director of the Russian space control centre, told Moscow's radio Echo the cosmonauts would carry out scientific experiments, repair leaks, and maintain the space station.

Proton rocket

However, in a comment that surprised western observers, he said that space officials would decide while the cosmonauts were in orbit whether to keep Mir going or to abandon it.

Meanwhile, technical problems with the Russian Proton rocket have forced a three-month delay in plans to send the service module of the International Space Station into orbit.

Alexei Zhiltsov, spokesman for the Khrunichev aerospace factory, said the launch date had been pushed back because of problems with the second stage of the Proton rocket. A design fault in the second stage engine had caused Protons to fail mid-flight in July and October of last year, an investigation into the failures showed.

Zhiltsov said engineers were working to overcome the problem but tests must be conducted ahead of any possible launch of the ISS service module, known as Zvezda. Proton will need to get two or three successful satellite launches under its belt before space officials will certify the Russian-designed rocket as ready to lift Zvezda into orbit, Zhiltsov said