Air Force Study Points To Reusable Orbiter

[ErnstBlofeld]

Aviation Week and Space Technology:

Newly declassified details of the analysis behind the U.S. Air Force’s decision to opt for a next-generation Reusable Booster System (RBS) reveal a long-term preference for a rocket-based, combined-cycle upper-stage orbiter over the nearer-term expendable solution.

The RBS plan is in development to replace the Air Force’s existing Evolved Expendable Launch Vehicles (EELV) beyond 2025, and aims to cut launch costs by 50% by combining a reusable first stage with expendable upper stages. The booster would take off vertically and return to a runway landing at the launch site.

Details revealed in the joint U.S. Air Force Space and Missiles Systems Center/Aerospace Corp. study at the American Institute of Aeronautics and Astronautics Space 2010 conference in Anaheim, Calif., show that while expendable upper stages will provide the initial capability, “a rocket-based combined cycle (RBCC) orbiter is the preferred far-term solution.” The RBCC configurations would adapt to the RBS first stage for vertical launch but return for a horizontal landing.

Although the study held out some optimism for RBCC proponents in the long run, its findings could be a telling blow for supporters of air-breathing turbine-based combined-cycle (TBCC) hypersonic space launch concepts. Study officials say even though the TBCC performance indicates greater specific impulse than rockets, the reusable booster turned out to be smaller, lighter and less costly.

Design details of a new reusable rocket and air-breathing combined-cycle hypersonic vehicle aimed at the long-term orbiter role have also been unveiled at Space 2010 by Astrox, a Maryland-based research and development company. The design was developed after the company was commissioned to perform a comparative survey of eight alternative two-stage-to-orbit (TSTO) configurations by the Air Force Chief Scientist Office, says Astrox President Ajay Kothari. These included Lockheed Martin’s Blackswift design for the Defense Advanced Research Project Agency, as well as Boeing’s FAST concept.

Edited September 23, 2010 by Rheo
snipped further