Science: Europe's space dreams stay in orbit: The European manned space programme is threatened by lack of cash, but its scientists remain hopeful that it will succeed. Peter Bond reports

TONIGHT, if all goes well, Ulf Merbold, a German astronaut, will blast off from the Baikonur cosmodrome in Kazakhstan for a 30-day trip aboard the Mir space station, the longest mission yet undertaken by a west European.

The forthcoming flight, Euromir 94, is the first of two co-operative ventures between the European Space Agency and Russia. A second flight, scheduled for next year, will last four-and-a- half months. One of the ESA's main reasons for investing dollars 50m in these long-term missions is to learn more about the problems human beings face living and working in zero gravity.

They are also seen as precursors to Europe's participation in the yet-to-be-built international space station. ESA officials expect European astronauts to commute regularly to the Alpha space station to carry out a wide- ranging microgravity research programme. ESA scientists, however, have little hands-on experience to guide them in choosing the most scientifically valuable and commercially profitable fields of research.

Merbold, the most experienced of the ESA's astronaut corps, will conduct 30 experiments during his month aloft. Most of these will investigate the effects of weightlessness on the body's muscles, cardiovascular system and neurosensory system. At the end of the flight, a record 100 blood, urine and saliva samples will be frozen and returned to Earth for analysis.

Scientists hope to be able to develop ways of counteracting the decline in performance due to the absence of gravity. Such countermeasures could then be available once scientist-astronauts start spending months at a time on board the Alpha station.

The two Euromir missions apart, the ESA's preparatory programme for the Alpha station looks thin. Budget constraints forced by the cash-strapped member states have meant that an ESA-dedicated Spacelab flight on the shuttle has been cancelled.

In addition, the ambitious programme to build a European spaceplane, called Hermes, was scrapped last year. Despite these setbacks, ESA officials continue to dream of being able to send its astronauts aloft inside a home- grown capsule perched on top of a European rocket. A quarter of a century after the agency's formation, such a capability would enable it to stand as an equal alongside the space superpowers of the United States and Russia.

The current plan envisages three elements of hardware. The first of these, the Ariane 5 rocket, is already under development and set for its maiden launch in October next year. As well as providing a launch capability for commercial satellites, this heavy-lift booster will deliver the ESA's two proposed capsules to the Alpha station.

One of these capsules will be an unmanned space tug known as the Automated Transfer Vehicle. This would be used to deliver add-on modules or unpressurised cargo to the Alpha space station. 'It could replace two progress flights or one shuttle flight,' says Dr Dieter Isakeit, senior programme engineer in the Manned Spaceflight Directorate. 'This would help prolong the shuttle's lifetime.'

According to Dr Isakeit, the 10- tonne craft should make its maiden flight around the year 2000. Initial rendezvous manoeuvres would be carried out automatically using navigational information from the Global Positioning System of navigational satellites. Final approach and docking would be completed with the aid of laser-optical sensors which are more sensitive than existing radar systems.

The most controversial piece of the package is the Crew Transfer Vehicle (CTV). It would carry four crew and weigh about 14 tonnes at lift-off. Under the current plan, its first launch would take place in 2002. Development costs could be spread out if Nasa adopted the CTV as its rescue craft for the Alpha station. The vehicle would be ideal for evacuating the station or returning sick crew to Earth.

A scaled-down version of this blunt-nosed capsule is set to fly on the second launch of the Ariane 5 in 1996. The 3-tonne unmanned prototype will be used to test its performance during atmospheric re-entry.

Europe so far has little first- hand knowledge of how to build a craft capable of surviving the intense buffeting and heating associated with re-entry or how to maintain guidance and control along a recovery trajectory.

Two designs are under study. One is an Apollo-type ballistic capsule; the other, which would return nose-first, would be more manoeuvrable. Aware of the budget pressures and lack of enthusiasm for human spaceflight among some member states, notably Britain, the ESA has already slashed its manned spaceflight programme. Dr Isakeit says the proposal which will go before the ESA Council of Ministers next year will be even cheaper: 'The whole programme will cost far less than dollars 5bn.'

But even if this scaled-down programme is accepted, how will the ESA gain the necessary space experience during the rest of the decade? Dr Isakeit explains: 'We have the possibility of another flight to Mir, or a flight on the American part of the space station, or one to the Russian segment. We could also have a Spacelab flight to Mir.'

A particularly favourable alternative would be to provide free Ariane 5 launches or specialised equipment for Alpha in return for ESA astronaut time on board the station.

So what does Dr Isakeit think are the chances of Europe's manned space programme getting off the ground? 'We have to invest in the future. Money only expresses the value of things you can put a price on. We are convinced that the programme is so interesting that the ministers will find the money.'

(Photograph omitted)