US space companies prepare for space station docking
Two US rocket companies are readying the first private space missions to the International Space Station (ISS).
SpaceX and Orbital both have multi-billion dollar Nasa contracts to supply cargo to the station, filling the void left by the retirement last year of the space shuttle.
California-based SpaceX has set the pace so far, having successfully launched its Falcon 9 rocket and Dragon capsule into orbit, and safely returning the capsule to Earth, in December 2010.
SpaceX is part of the new wave of commercial ventures that Nasa hopes can help reduce the cost of going into space.
The company says it could launch for the ISS as soon as 30 April.2012.
But the company is now looking to move quickly, with a static launch test and a first launch into orbit scheduled for the summer, and a possible rendezvous with the ISS in the autumn.
Frank Culbertson, a former