NASA has designed a reusable manned deep space exploration craft using bigelow modules.

The suggested NASA version is a tubular-looking spacecraft that could serve as a reusable vehicle, holding a crew of six and enough supplies for a two-year expedition. This vehicle would be built in orbit and, if funded, could be ready for space missions by 2020.

Launchspace originally suggested that the ISS might be a good base of operations for such a transporter.

However, NASA suggests it would be assembled from expandable structures, such as Bigelow's inflatable habitats. Part of the vehicle would contain a ring centrifuge to provide partial gravity. A radiation-mitigation system would be needed to project the crew. This might be done with tanks of water or liquid hydrogen slush.

Since Nautilus is intended to be a multi-mission exploration vehicle, it could incorporate mission-specific systems such as propulsion for high delta-V missions, or extra life support for longer coasting periods. As originally suggested by Launchspace, this approach would relieve the need to carry heavy atmospheric ascent and entry systems and structures.

However, we still need to ferry the crews from Earth surface to low orbit. At the moment, the US does not have such a vehicle beyond mid-2011, when the Shuttle will be retired. Hopefully, a replacement option will soon arrive.

NASA estimates the cost to be about $3.7 billion and construction time to be at least five years.

Extremely cool but $3.7B and ready by 2020 my arse! If NASA were put in charge of this that would grow to at least $100B and take until 2035. Not a chance in hell of this baby getting funded, unless it is private. One can only hope.