Utah-based Alliant Techsystems, or ATK, announced the new project here at the first Spacecraft Technology Expo, where thousands of government and industry officials have gathered to discuss innovative new technologies and the future of human spaceflight.

ATK had already been working on a new private rocket, called Liberty, which it submitted as a contender in the second round of NASA's Commercial Crew Development program last year. Ultimately, the Liberty rocket was not selected to receive funding, but ATK continued development of the booster under an unfunded Space Act Agreement with NASA. As part of this arrangement, NASA shares its expertise in designing and testing the rocket but does not provide money for the project.

Now, ATK has unveiled plans for a complete launch system centered around the Liberty rocket. The design includes a space capsule to carry passengers to destinations in low-Earth orbit, such as the International Space Station, said Kent Rominger, vice president and program manager for Liberty.