GRAHAM WARWICK / HUNTSVILLE, ALABAMA

The US Department of Defense (DoD) is mulling the results of a US Air Force/NASA study into joint development of a second-generation reusable launch vehicle (RLV). The 120-day study identified benefits for the USAF, but joining NASA's Space Launch Initiative (SLI) would require substantial investment from the DoD.

Making the SLI a joint programme could also block international participation in development of a second-generation RLV, according to US and European officials attending the American Institute of Aeronautics and Astronautics future RLV symposium on 11-12 April in Huntsville, Alabama.

The USAF is interested in developing an unmanned reusable spaceplane capable of rapidly replenishing, or "surging", space assets and of striking targets quickly at long range. For this, the spaceplane could deliver the proposed Common Aerospace Vehicle, a conventional re-entry vehicle carrying a 450kg (1,000lb) penetrator warhead, four small bombs or six mini missiles.

NASA plans to decide in 2006 whether to begin full-scale development of a two-stage-to-orbit RLV that would enter service in 2012. The USAF wants to fly an early prototype in 2008-09 to validate military utility and provide a residual capability "to address the 2010 threat", Col Michael Wolfert told the conference.

The USAF's proposal is "not consistent" with NASA's flight demonstrator plans under the $5 billion SLI programme, says Marshall Space Flight Center director Art Stephenson, adding: "To get there will need a lot more funds than in SLI, and soon." NASA plans to downselect to three competing second-generation RLV architectures in November. It hopes for a DoD decision by then.

"I am hopeful we will have one programme, not two, because the USA cannot afford to develop one for NASA and one for the USAF," says Stephenson. Although previous military spaceplane development programmes foundered, Wolfert says: "The threat environment demands the DoD look at a military spaceplane. The DoD has to decide: do we have the funds or do we miss the opportunity again?"

A single national programme could make international participation in development of a second-generation RLV problematic. "We need to look at the technology transfer issues," says Wolfert. But European officials at the conference said US enthusiasm for co-operation has cooled since 11 September.

The European Space Agency (ESA) is seeking Russian participation in a programme to develop a fully or semi-reusable RLV by 2020. ESA hopes to finalise plans for a future launcher preparatory programme by July and to launch the six-year, €750 million ($652 million) programme by year-end. Japan also aims to have an RLV operational by 2020.

Source: Flight International