Leading US scientists have tried to pull the plug on the project by arguing that the huge amounts of money which are being ploughed into the ISS are stifling other areas of space research. Nasa denies those claims. But many observers wonder whether the station will provide value for money. Doubt has also been cast on the usefulness of the ISS on a scientific level. Some scientists wonder if the research into protein crystals, which benefits from the near absence of gravity in space, could actually be carried out on Earth.
Shuttle astronauts armed and ready Links to more Space station stories are at the foot of the page.