NASA has selected three teams to define concepts for a re-usable launch vehicle to replace the Space Shuttle and to design an X-33 technology-demonstrator for the ultimate RLV, which would be an unmanned, fully re-usable, single-stage-to-orbit launcher capable of carrying a 18,000kg payload. The RLV, is expected to be flown, in about 2005.
The three teams, led by Lockheed Martin, McDonnell Douglas and Rockwell, were each awarded $8 million cost-sharing contracts for the initial 15-month concept-definition and design phase. NASA plans to select one or two teams in the second half of 1996 to proceed with design and production of the X-33, leading to a first flight in 1999.
Rockwell's Victer says that the X-33 will be half the size of the eventual RLV and will carry no payload. The company's concept is for a wing-body vehicle, which will take off vertically and land horizontally. Liquid-hydrogen/liquid-oxygen propulsion will be used and composite materials will be employed extensively, including for the liquid-hydrogen tank.
Lockheed Martin is studying a lifting-body design, while McDonnell Douglas, teamed with Boeing, is pursuing a vertical take-off and landing design based on the Delta Clipper - Experimental (DC-X) technology-demonstrator developed for the US Ballistic Missile Defense Organization and subsequently taken over by NASA (see box).
A durable thermal-protection system will be a key factor in meeting the goal of reducing turn-around time from 80 days for the Shuttle to seven days for the RLV, and down to 3.5 days in an emergency, Victer says. The RLV will be automated and unmanned, but ultimately will be man-rated, enabling the vehicle to carry passengers as one of its payload, he says.
Rockwell's X-33/RLV team will be led by the company's Space Systems division, the Shuttle Orbiter prime contractor, and will include its North American Aircraft (composite structures) and Rocketdyne (propulsion) division. Other members are, Northrop Grumman (composite structures, rapid prototyping and integrated vehicle health- management), Orbital Sciences (commercial launch services), FedEx (operability requirements and operational concepts) and ten NASA and US Air Force centres.
Source: Flight International
