Lockheed Martin Corp.Palmsdale, Calif.

X-33 VentureStar reusable launch vehicle

It was all systems go at Lockheed Martin this July when NASA selected the aerospace enterprise to design, build, and test the first major new space vehicle for the U.S. in a quarter century. Lockheed Martin's concept -- the single-stage-to-orbit X-33 VentureStar reusable launch vehicle -- prototypes commercial space fleets for the new millennium and truly pioneers the next frontier. The X-33 changes space travel as we now know it -- rocket, boosters, and fuel tanks that separate from a shuttle -- with a vehicle that takes off vertically, climbs into orbit with a single stage, and lands on a conventional runway. Although Lockheed was working on single-stage concepts in the late 1980s, the results were marginal, says Bob Baumgartner, X-33 deputy program manager, Lockheed Martin Skunk Works. "In 1992 we started getting back to being involved in single-stage orbit because we felt that single-stage orbit, a low-cost reusable launch vehicle [RLV], was a true national need." Lockheed's reentry into RLVs culminated in the NASA announcement this summer. Since then, Lockheed has completed a systems requirement review and a preliminary design review and is preparing for a critical design review next summer. At that time, drawings will be completed and detailed fabrication will begin. The X-33 demonstrator model is scheduled to fly by Mar. 1, 1999. The four-year launch-vehicle program begins December 1999, meaning full-scale test flights should begin in December 2003 with operational service in late 2004. "Several new technologies were needed to make the single-stage orbit work," says Baumgartner:

  • Propulsion system: Propulsion is achieved with linear aerospike rocket engines, fueled by liquid hydrogen/liquid oxygen (LH2/LO2). "It's a new high-technology vehicle in that we're just using safe nontoxic LH2/LO2 to power all the systems on the vehicle": main propulsion system, reaction-control system, and turboalternator, a device that creates electricity for the all-electric power system (no hydraulics). There will be two LH2/LO2 engines on the demonstrator and seven on the full-scale vehicle.
  • All-composite structure: All large vehicles to date have been made of metal, and this change will result in substantial weight savings. An emphasis on weight reduction is a major means to reducing operational costs -- reportedly by 90%.
  • Metallic thermal protection system: Robust 18-in.-by-18-in. metallic panels cover the craft, instead of the much smaller ceramic tiles found on shuttles that frequently need to be replaced.
  • Lifting body: Lifting-body aerodynamics create a craft that surrounds the tanks and generates enough lift to land, which eliminates the need for wings and fuel to land, and also reduces weight.
All the innovation for the X-33 won't be airborne. Wally Eshleman, X-33 operations manager, says Lockheed developed a streamlined ground system called "runway-to-path-to-orbit concept." The vehicle lands on a horizontal runway; the vehicle is towed to launch pad and plugged into launch mount and umbilical plates while in horizontal position; a shelter is rolled over the vehicle and launch mount for maintenance, processing, and payload integration; shelter is rolled away; vehicle is rotated to vertical, fueled, and takes off. Repetitive payload processing is done offline in parallel and uses reusable and interchangeable containers. Eshleman says reliability and maintainability analysis shows the runway-to-takeoff turnaround can be achieved in seven days, or 3.6 days if the vehicle is already processed and waiting to accept the payload. The VentureStar promises drastic cuts in the cost of putting commercial or military payloads into space. "The key thing is that the operational vehicle will be commercial development," says Baumgartner. "We had to show NASA and, just as important, ourselves that we can turn a profit by developing an operational launch system, fielding it, and launching payloads to orbit." Lockheed Martin and NASA are partners for the X-33 stage -- both contributing money -- and the next full-scale operational stage will be funded entirely by Lockheed Martin and investors.
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.