What future for the space station?

The ISS: Towards 'humanity's future among the stars'

By the BBC's Richard Hollingham, who watched the launch of the first section of the International Space Station from Baikonur in Kazakhstan in 1998.

It was heralded as humanity's next step into space - the International Space Station (ISS) was supposed to unite countries in a common goal to explore new frontiers.

When will the ISS get its first crew?

But the project, in some senses a successor to the Russian Mir space station, is now several years behind schedule, billions of dollars over budget and still uninhabited.

Back in November 1998, the story was very different. After years of planning, the first stage of the giant orbiting laboratory had just been launched. Representing unprecedented co-operation between Russia, the United States, Europe, Japan and Canada, the ISS would eventually be larger than a football stadium.

More than a year on, it consists of only two units, and the module that will make it habitable has yet to make it off the launch pad in Kazakhstan. Zvezda, as it is known, is now unlikely to fly for at least another six months.

International politics

So where has it all gone wrong? "The ISS is very complicated, it's a very massive piece of engineering, it's very expensive and worst of all it's very political and very international', says Paul Murdin, from the British National Space centre.

 BBC Archive: Zarya is launched

Co-operation in space between the US and Russia goes back to the early 1970s, culminating in the Shuttle-Mir missions of five years ago. There is a mutual benefit in joint research. The US needs Russian expertise and the Russians need US money.

There are technical problems with the Proton rocket

But the latest problem centres on technology. After two failures, the Proton rocket, which will carry the delayed service module, is grounded while problems in its fabrication are corrected.

And, for as long as Zvezda remains on the ground, space commentator Brian Harvey believes Russian interest will be redirected to its old Mir programme.

"They are faced with a choice of trying to run a rather old and serviceable station of their own, or being a junior partner in an American-led enterprise."

Billions of dollars

The Americans keep reminding the Russians that they are in charge, says Harvey.

"The Russians have felt they've been put into a rather junior role and they don't like that."

Zarya and Unity are slowly falling to Earth

The whole ISS project is likely to cost anything between 20 and 100 billion dollars. Extra missions are now planned to maintain the existing two modules and to boost their orbit - they are coming closer to the Earth all the time.

Nasa spokesman Dwayne Brown remains defiant that the project will succeed.

"The International Space Station is being built, it will be completed, and while there will be delays, it will be successful."

When the first stage of the International Space Station, Zarya, was launched from Baikonur in November 1998, the heads of the space agencies involved said the event was the next step to humanity's future among the stars. But there have to be real doubts over whether the project will ever be completed.