The most detailed plan comes from SpaceDev, which built SpaceShipOne's rocket engine. The design for SpaceDev's Dream Chaser combines enhanced versions of that craft's hybrid rocket motors--burning rubber and nitrous oxide--with a winged rocketplane based on the X-34 that was designed by Orbital Sciences and NASA. SpaceDev likes the X-34 because NASA already has a huge database on its aerodynamic performance; for NASA, it could be a chance to fly a useful research vehicle using SpaceDev's proprietary rocket engines. CEO Jim Benson says the vehicle would be strapped to three million-pound hybrid boosters to go all the way to orbit. The key to this five-year, $150-million project, he says, is that hybrid rockets are "almost embarrassingly cheap" when produced in quantity. Benson hasn't committed to
a try for Bigelow's prize, however, and actually might not do so. He doesn't think the private sector will fully fund an orbital project, which is why he's working with NASA. "Who cares who pays for it," he asks, "as long as we get a safe, affordable vehicle?"