Nice view: Hotel guests could soon see planet Earth from their window.© NASA

It makes the X prize look easy. The winning craft in the latest competition for civilian space flight will need to have spectacular technology rivalling that of NASA, according to rules set out on 8 November.

'America's Space Prize', worth $50 million, is being offered by Bigelow Aerospace of Las Vegas, Nevada, a company established in 1999 by hotel magnate Robert Bigelow to build an orbiting inflatable space hotel. Bigelow also runs the hotel chain, Budget Suites of America.

The prize will be awarded to a craft that can take a crew of at least five people to an altitude of 400 kilometres, and complete two orbits of Earth. This feat will have to be repeated within 60 days. The craft must be able to dock with Bigelow's space hotel (which he hopes to launch in 2008), and be capable of staying docked in orbit for six months.

The deadline for these flights is 10 January 2010, allowing very little time for aerospace developers to prepare their entries.

Transport alternatives

Bigelow had hoped to buy Russian Soyuz craft to service his orbiting hotel. But since the crash of the Space Shuttle Columbia on 1 February last year, NASA has relied on Soyuz to deliver supplies to the International Space Station.

Bigelow believes that after the space-shuttle fleet is retired, NASA will still need to use the Russian ships as space workhorses. This has upped the going price for a Soyuz, and forced Bigelow Aerospace to look for alternative transport systems, he told the space news website Space.com.

Bigelow Aerospace is also offering hefty contracts for any craft that can begin bringing customers to the space hotel.

Space rules

The rules of the competition do not allow government funding for the projects, and teams from outside the United States are excluded from entering. This may be a response to fears that regulations designed to stop the export of military hardware from the United States could hamper progress in commercializing civilian space flight by restricting trade.

The rules of the prize also state that no more than 20% of the craft's hardware must be expendable. Many space shots still rely on huge rocket boosters that are lost during launch, and coming up with reliable alternatives will be a significant hurdle for competitors.

The Ansari X Prize stimulated a huge investment in civilian space flight, and was won on 4 October when SpaceShipOne and its pilot reached an altitude of 100 kilometres for the second time in two weeks. The $10-million prize money was handed over to Burt Rutan, who led the Scaled Composites engineering team responsible for the craft, at a ceremony in St Louis, Illinois, on 6 November.

Since then, the Ansari Foundation has announced that an annual X Prize Cup will be awarded for feats of sub-orbital space flight.