Space Shuttle solid rocket motor provider Alliant Techsystems has released details of its proposed launcher for PlanetSpace's bid for NASA's Commercial Orbital Transportation Services (COTS) demonstration programme.

PlanetSpace has been selected as a finalist for the agency's $175 million Space Act agreement, to be awarded in February.

The three-stage COTS launcher consists of a first stage with a 2.5-segment derivative of the Shuttle's four-segment reusable solid rocket motor (RSRM) a Castor 120 solid rocket, used on Lockheed Martin Athena and Orbital Sciences Taurus launchers, for its second stage a Castor 30 third stage and an Orbit Adjust Module, which has flown on the Athena.

ATK says its COTS launch vehicle can place up to 6,725kg (14,800lb) into Low Earth orbit for International Space Station missions 2,800kg into geosynchronous transfer orbit 1,885kg into a trans-lunar insertion and 1,360kg for Mars science missions.


"A big advantage of the design is that it is modular in nature. We can fly the entire vehicle for a COTS-class mission, or we can fly a smaller payload by flying all but the RSRM first stage," says advanced programmes director Joel Crook. ATK has letters of intent from three customers for the small launch vehicle. "We plan to fly the first small launch vehicle in September 2009, and launch our COTS demonstration vehicle in December 2010," he says.

ATK expects 709kg more payload capability for ISS missions with planned composite-case and solid-propellant upgrades for the first stage. Launches could also "serve as a flying testbed for potential Ares I [crew launch vehicle] and Ares V [cargo launch vehicle] booster upgrades", the company says.