GRAHAM WARWICK / WASHINGTON DC
Contractors study orbital spaceplane to be launched on expendable booster and able to carry crew or cargo
NASA's Space Launch Initiative (SLI) could take a new direction before year-end, with the US space agency possibly opting to develop a crew- and cargo-carrying vehicle that would be launched on top of an expendable rocket. Development of a second-generation reusable launch vehicle (RLV) to replace the Space Shuttle would be delayed.
SLI contractors are studying an orbital spaceplane that could evolve from a crew rescue vehicle to be launched unmanned to the International Space Station (ISS), into a crew transfer vehicle launched with crew aboard. It would initially use an expendable booster, but would eventually be launched on the planned two-stage-to-orbit (TSTO) RLV.
"NASA is leaning towards moving the orbital spaceplane earlier in the schedule and launching it on an expendable," says Lockheed Martin SLI programme manager Bob Ford. Lockheed Martin's Atlas V, Boeing's Delta IV and the European Ariane V are potential launch vehicles. "The TSTO would move to the right," he says.
The probability of crew loss would not be as low using an expendable booster as the goal of 1 in 10,000 flights set for the second-generation RLV, but would be "acceptable", Ford says. While contractors are looking at what would be required to human-rate their expendable launchers, "the first flights may be an uncrewed vehicle going up to the station", he says.
NASA administrator Sean O'Keefe cancelled the ISS crew rescue vehicle (CRV) earlier this year, limiting the station to a three-person crew instead of the seven planned and severely constraining the research that can be conducted on board.
In the CRV's place, he ordered studies of a vehicle capable of carrying crew and cargo both ways. Boeing, Lockheed Martin and Northrop Grumman have included such a vehicle in their preferred SLI architectures.
New associate administrator for aerospace Jerry Creedon has ordered a review of the SLI programme. Industry believes NASA could opt for an evolutionary approach enabling deployment of a crew rescue capability for the ISS as early as 2008, while continuing development of a second-generation RLV to become operational early in the next decade. "NASA is looking for the most optimal approach," says Boeing director of advanced space and launch systems Kevin Neifert. "Develop it all at the same time or do the crew vehicle first and evolve to the next-generation RLV over time?"
Source: Flight International
