MILNET: X-33 Aerospace Test Bed for VentureStar.

• Wingspan: ?
• Length: 67 feet
• Weight: 273,000 lbs
• Speed: ?
• Ceiling: Trans-Atmosphere/Orbital
• Engines: Linear AeroSpike (rectangular)
• Crew: 0

The X-33 is a Lockheed Martin test bed to be used for testing of the VentureStar Shuttle Replacement. Awarded the contract in October of 1996, Lockheed Martin will produce the X-33 to prove several of its key concepts for VentureStar:

• Aerospike Engines - hot fuel gas is expended from cells in a rectangular engine design, which looks like a series of holes in a thin rectangle. The engines are used to steer by changing gas velocities in series of blocks. For instance to turn left, gas jets in a hypothetical 12 jet block (two rows, 6 each), the left three jets of the top and bottom row are at set to low velocities while the right three jets of the top and bottom rows are set to full power. Similarly, the gas jet velocities can be set to add or subtract pitch. Note: The diagram at right shows the downward pitch controlled by adding thrust at the lower row of aerospike jets...remember that this engine outlet is at the rear of the aero-spacecraft, thus maneuvers the tail. Thus to control downward you apply thrust to pitch the tail upward, and this forces the nose down (opposite to an elevator on an aircraft where you pitch the rear elevators down to force the tail upwards).

• Carbon Fibre skin sans Shuttle tiles, and reenters at a much gentler rate than the shuttle.

• Liquid Hydrogen and Oxygen fuels - not untried but certainly not as potent as the hypergolics used on the shuttle engines.

But the X-33 and VentureStar follow on are expected to provide much safer operation, faster turnaround, better reliability and require less overall maintenance hours. The reasons are:

• self contained cargo pallet/container - which is delivered to the launch site by the manufacturer, and inserted as a unit into the cargo bay.
• maintained in a hanger in the horizontal position since there is no booster or external tanks.
• only five of seven engines necessary to achieve orbit, and if orbit is not acheivable, the engines can be throttled back for a go around and landing.
• while a glided landing is possible, the X-33 and VentureStar follow-on are designed for a powered landing.

The design of the X-33 is a lifting body design, perhaps based upon the supposed Aurora program, a hypersonic trans-orbital aircraft used to replace the SR-71 Recon aircraft. The rapidity of the the delivery of the design and the basis of much of it on hitherto unknown technologies, combined with the designer -- Lockheed Skunk Words -- leads many to believe that if the U.S. Air Force did not deply such an aircraft, there were certainly some tests leading up to such an aircraft.

The craft is essentially a delta winged lifting body, with huge surface area and tiny, stubby wings to aid in steering rather than lift, and entirely for the landing phase, not during liftoff. The lifting body design coupled with the engine design, will allow the craft to take off vertically and land horizontally, and without the need for booster rockets or an external tank.

The X-33 is to be an unmanned prototype to be used in testing prior to the approval of the build of the full size VentureStar aero-space craft.

Diagram comparing the X-33 prototype specifications with those of target production vehicle, VentureStar.

First flight of the X-33 is expected in March of 1999. The VentureStar is expected to fly in the early months of 2004.

The VentureStar will carry some 40,000 pounds of payload, itself weighing in at approximately 2,186,000 pounds wet, and will have a length of nearly 128 feet.

milnet@milnet.com
Last Content Updated: September, 1997