Future of space station threatened

The loss of the Columbia leaves the international space station in an extremely precarious state. Currently manned by three astronauts, Nasa's Ken Bowersox and Don Pettit and Russia's Nikolai Budarin, their only hope of return to Earth lies with a Russian Soyuz vehicle attached to one of the station's modules.

The trio are not in immediate danger, but the continued operation of the orbiting laboratory is severely compromised. With no permanent crew aboard, the station can operate in a 'dormant' mode as long as occasional maintenance is performed by visiting astronauts. However, the longer the $30 billion (£18bn) station goes unoccupied, the greater the chances that it will deteriorate to an uninhabitable state.

Nasa's dream - of opening space in 1981 with a reusable spaceship, the shuttle, then permanently manning an outpost in orbit - is now threatened with extinction.