Developing the X-33 VentureStar re-usable launcher prototype will present a difficult challenge.

Tim Furniss/LONDON

"The VentureStar is going to revolutionise the world of space launch-it is going to open up a thrilling new frontier in space - the business frontier", says Micky Blackwell, president and chief operating officer of Lockheed Martin's Aeronautics sector. He may be right, but there is much development to be done yet - including that of the linear aerospike engine.

The hyperbole surrounding NASA's selection in July of the Lockheed Martin Skunk Works to develop the X-33 VentureStar obscured the fact that the company had merely been awarded a contract to build one sub-orbital demonstrator vehicle, to optimise the design of a potential fully fledged, single-stage-to-orbit (SSTO), re-usable launch vehicle (RLV), and launch it in March 1999. An RLV with another "X" designation could be flown as a cargo vehicle in 2003 and, by 2005, could be ready for manned operation as a replacement for the Space Shuttle. The X-33 is the most advanced part of NASA's three-pronged prototype RLV programme, which also includes the McDonnell Douglas DC-XA Clipper Graham technology demonstrator and the Orbital Sciences X-34 Mach 8 technology-verification craft. The future of the Clipper is in doubt, however, after a landing accident at White Sands Missile Range, New Mexico, on 31 July (Flight International, 7-13 August).

Development of an operational RLV depends on whether industry can be persuaded to invest $5 billion or more in the project and whether NASA will play some role in supporting it. Lockheed Martin's business plan anticipates Government assurance that the VentureStar. will be used for several launches. Without those guarantees, private investment will be more difficult to obtain. It is possible that a joint government-industry corporation could be established to operate the new vehicle.

If the 990t, 38m-long RLV is built, three vehicles would be flown a total of 50 times a year, cutting the cost of flying into orbit from $20,000 per kg of payload to $2,000/kg. The RLV's 23t payload-carrying capacity could be as high as that of the Space Shuttle, the orbiter of which has roughly the same dimensions as the RLV. The total Shuttle system is 56m high and weighs just over 2,000t. The VentureStar proposal, which has been designed to carry 94% of the payloads likely to constitute the projected market at that time, will fly with standardised payload containers, involving off-line processing, with a small launch team of perhaps 50 people, "perhaps even just five", Blackwell says. The RLV could also be a major vehicle in the commercial-launcher market. Even when the vehicle is manned, passengers would fly in "containers". The RLV will open the space frontier "-not just to special NASA astronauts but -hundreds of [ordinary] people a year", says Daniel Goldin, NASA's Administrator.

There would be no crew - a culture shock which may make this manned RLV version unacceptable to pilots and passengers alike. An alternative may be to develop and crew a transport vehicle as part of the payload system, which would be deployed, ready to fly, in to orbit.

Meanwhile, Lockheed Martin is investing $212 million in the X-33 half-scale, 20m-long, 124t prototype of the proposed RLV, while NASA is committing $941 million to this RLV Phase 2 programme. NASA will help develop the high-risk technologies which industry cannot realistically afford to do, but "-will not build the vehicle nor operate it", says Goldin.

The rapid prototyping and low-rate production of the new aerospace craft was suited to the Skunk Works. "VentureStar is a perfect project for the Skunks and they are thrilled to be working on it," says Blackwell. Lockheed Martin's Space and Strategic Missiles, Information, Technology and Electronics divisions will also be involved, under the management of NASA's Marshall Space Flight Center, Alabama.

Mission speeds

The automatic vertical take-off and horizontal landing craft will be flown on 15 or more missions after March 1999 to the end of that year. The X-33 VentureStar demonstrator will reach maximum altitudes of 260,000ft (80,000m) at speeds of Mach 15 after launch from Edwards AFB, California.

The first mission will attain Mach 3 and the second flight will reach Mach 7. The third flight will attain the projected Mach 15. Landing sites at Silurian Lake and China Lake, California; Dungway Proving Ground, Utah; Moses Lake, Washington; and Malmstrom AFB, Montana, are being considered.

The launch site for the fully fledged RLV has not been selected, although high-altitude, equatorial launch sites are being considered from Equador to Kenya, as well as the more conventional northerly, sea-level Cape Canaveral in Florida or Vandenberg AFB, California, from where only flights carrying smaller payloads can be flown. Supporters of White Sands, New Mexico, are also lobbying Lockheed Martin.

X-33 industry partners are Rockwell's Rocketdyne division, which is developing the aerospike engines and other propulsion systems; AlliedSignal, the inegrator of $130 million worth of subsystems; Rohr, supplying the thermal-protection system; and Sverdrup, which will build the launch equipment. Another major contractor, Aerojet, has a contract worth $30 million from Rocketdyne to build the gaseous oxygen/hydrogen reaction control system. Menasco will supply two ship sets of nose and main landing gear to AlliedSignal.

Lockheed Martin's sub-orbital demonstrator will have a tightly integrated lifting-body design, with all-composite conformal integral tanks, a combined aft body and engine structure, no Shuttle-style tiles, no solid rockets, no hydraulics and no hypergolic propellants (those which react spontaneously when mixed). Not everything about the X-33 will be black or white - it will be metallic grey.

The VentureStar dream: a fully reusable, commercial orbital transportation system, to replace the Space Shuttle by 2005

Source: Flight International