Science: 2003: a space odyssey

In five years' time, a new International Space Station is scheduled to be in orbit. Charles Arthur asks why

Most people will have heard that the Mir space station celebrated its 12th, and probably least safe, year aloft last week. What a year it was: an onboard fire, a crash with a supply ship which punctured a crew module, repeated computer crashes, and heart palpitations diagnosed in one of the Russian cosmonauts.

In that context, it sounds surprising to hear that within five years, there should be another space station aloft - as big as two football fields, weighing 450 tonnes, and containing 43,000 cubic feet of working space. It will cost more than any collaborative project ever. After the disasters on Mir, can they be serious?

You would think not. But the momentum behind the International Space Station project appears unstoppable. Although - or perhaps because - it is the largest and most complex multinational co-operative science and engineering ever, and will cost between $50bn and $100bn to build, launch and operate for a decade, it is now seem as inevitable. (If you're keen, you can even get your International Space Station Foundation MasterCard Credit Card, although it doesn't guarantee you a spot on board - just a nice picture on the front when you use it.)

But the idea first proposed by Ronald Reagan in 1984, for an $8bn permanent space station, is moving closer to fruition. This June, the first component of the station will be launched from a site in Baikonur, Kazahkstan.

Funded by the US and built by Russia, the control module alone weighs 20 tonnes. The news of its shipment from its Moscow factory in January moved Randy Brinkley, the International Space Station programme manager at the US space agency Nasa, to say happily: "The year of the International Space Station is 1998."

However, some people are asking why they really need another floating toolbox, and how the costs can be justified. Dale Bumpers, a Democrat Senator, attempts every year to halt funding for the ISS: "One shuttle flight to the space station will cost almost as much as the entire budget ($454m) of the National Institute on Aging," he complained recently.

What will astronauts do on the ISS? First, they'll build it - a slow process which will require 45 assembly flights to put together its 100 components, with completion scheduled for 2003 - though even before then it will be feasible to carry out experiments, as with Mir.

Once finished, it will provide access for researchers ("from around the world", emphasises Nasa) to permanent, state-of-the-art laboratories in weightless conditions.

Current plans are for a crew of up to seven people using five complete pressurised laboratories, with attached external sites for research. It will also be a very useful jumping-off point for human exploration of the Solar System, if that goes ahead.

So what sort of experiments do they plan? Already scientists have begun lining up their plans. One will be a cheap magnetic spectrometer that will search for antimatter - particles with the same weight, but opposite characteristics, to normal ones such as electrons and helium. Others will investigate the effect of microgravity on producing metal alloys, the ways in which cells deteriorate in bones with age, and how to produce a laser-cooled atomic clock 10 times more accurate than any built on Earth.

The ISS's governmental backers are understandably keen to get as many commercial companies as they can on board. But the evidence of years of space travel is that terrestrial companies are reluctant to put their money into pies in the sky: they will pay to put satellites into orbit, especially if they can bounce telephone or TV signals off them, but (despite the urban myth about Teflon) very few inventions have come from space work. And very few companies rush to Nasa with ideas for experiments they want to see done in space.

Even so, backers suggest that once the ISS is built, pharmaceutical companies will be interested in growing protein crystals - which form larger and clearer shapes in microgravity than on Earth. The growing emphasis on protein-based work (as a consequence of gene research) on Earth could make that a hit, because it will let the firms make better drugs, tailored to affect proteins whose behaviour is better understood as a result of the space work.

But only the very largest drugs companies could likely afford to hire that space in space - and they are exactly the ones which will have other methods of investigating promising chemicals on the ground quickly and efficiently.

Such is the cost element that one materials scientist told the science journal Nature "If Rumpelstiltskin took straw into space and spun it into gold, he'd still lose money."

And the spiralling cost of the station is only part of the worry. Privately, Nasa admits that the much-delayed station - which was meant to have been completed in 1994 - may have missed its best chances. Then there is the fact that the ISS has actually been scaled down in size: President Reagan envisioned a much bigger beast than is now being transferred from the drawing boards. Shrinking budgets have hit space programs in every country, and that in turn has meant that the fabric of the station is being paid for in part by money that had been earmarked for facilities. "We'll build a house, but not have any furniture," grumbles Lawrence Young, who heads Nasa's Space Biomedical Research Institute SBRI.

Still, there are some who remain optimistic. At Boeing, Nasa's prime contractor for the ISS, Doug Stone, the programme manager, cites benefits the research will bring to health care back here. There's the value of international co-operation to American foreign policy. There are the possibilities for serendipitous high-tech discoveries.

But he sees something more too. "The ISS is about people of all walks, all races, many political systems all coming together to reach outside ourselves and accomplish something far greater than any of us could accomplish alone. To attempt what seems impossible, to reach beyond your grasp, to dare great deeds - this is an important part of being human." If fine words could launch a space station, Stone would have done his job already.