Private firms to haul ISS cargo

By Paul Rincon Science reporter, BBC News

The Dragon capsule is designed to carry cargo or crew

Cut off in the seclusion of space, crew members living aboard the International Space Station (ISS) depend on regular deliveries of air, water, food and fuel for their survival.

But when the ageing space shuttle fleet is retired in 2010, the US space agency (Nasa) will lose a principal means of ferrying crew and cargo to the ISS.

The shuttle's replacement - Ares-Orion - will not enter service until 2015 at the earliest.

And in April, Nasa told legislators it would stop asking for Congressional permission to buy cargo space on Russian Progress re-supply vehicles after 2011.

I don't think the market can support more than two companies. And it's going to be hard for it even to support two Antonio Elias, executive VP, Orbital

That leaves the US dependent on European and Japanese spacecraft for delivering supplies to the space station.

But Nasa has also been pursuing a commercial approach.

Three years ago, the space agency took the unprecedented step of fostering the development of private spacecraft designed to carry crew and cargo to the ISS.

It offered $500m (