Aerospace Technology Development

X-33 Shields Take the Heat

NASA'S F-15B AERODYNAMIC FLIGHT FACILITY aircraft has successfully completed flight testing of Thermal Protection System (TPS) materials, or heat shields, to be used for the X-33 Advanced Technology Demonstrator at NASA's Dryden Flight Research Center, Edwards, California.

Thermal protection systems perform in temperature ranges from minus 250 degrees Fahrenheit in the cold soak of space to entry temperatures that reach nearly 3,000 degree Fahrenheit. They are used on spacecraft to protect them during flight, primarily as a "heat shield" during reentry into Earth's atmosphere. Although the X-33 is a suborbital technology demonstrator, it will encounter an extreme heating environment similar to what such a vehicle will encounter during orbital space flight and atmospheric reentry.

Scheduled to begin test flights in July 1999, the wedge-shaped X-33 is one of three demonstration prototypes of the Reusable Launch Vehicle (RLV) program, leading to the next generation of commercially developed and operated single-stage-to-orbit vehicles. The overall goal for the RLV program is to reduce the cost of access to space and putting payloads in space, as well as to promote the creation and delivery of new space services and other activities that will improve and increase U.S. economic competitiveness.

"This is an excellent example of all the testing the X-33 program is performing on the challenging technologies we need for a reusable launch vehicle," said Dan Dumbacher, NASA's X-33 deputy program manager.

The TPS material samples include metallic Inconel tiles, soft Advanced Flexible Reusable Surface Insulation tiles and sealing materials. They were flown attached to the forward-left side position of the F-15B's Flight Test Fixture II, a device attached underneath the aircraft to carry experiments. In-flight video from the aircraft's on-board video system, chase aircraft photographs and video cameras documented the condition of the TPS materials during flights.

The F-15B reached an altitude of 36,000 feet and a top speed of Mach 1.4 during the series of six flights at velocities above the speed of sound. No damage or signs of wear from high speed or maneuvering were apparent on any of the TPS materials. This provided the X-33 team more information about the stability of the materials to successfully protect the X-33 and follow-on vehicles in the harsh environment in which they will fly.

TPS materials can be applied commercially to situations and structures subjected singly or repeatedly to high heat fluxes. Such applications include firefighting equipment, insulation materials, the automotive industry for engines, industrial and manufacturing machinery, roof coatings in high fire-danger areas, safes and safety deposit boxes, and electrical wiring, hoses or pipes carrying volatile materials.

Private industry will build and operate the RLV in the first decade of the next century, and NASA will be a customer. The program has implemented the National Space Transportation Policy, issued by the White House in 1994, and will accelerate the development of new launch technologies and concepts to contribute to the continuing commercialization of the national space launch industry.

For more information, contact David Richwine at Dryden Flight Research Center.
Call: 805/258-2710, E-mail: dave.richwine@mail.dfrc.nasa.gov
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Heat shields successfully protected the X-33 prototype in recent tests, demonstrating how the vehicle will handle extreme environments when flying as part of the commercially developed and operated Reusable Launch Vehicle program of the future.