NASA News Release 97-023
April 10, 1997

Scale models of the X-33 flight test vehicle, a technology demonstrator leading to the nation's next-generation space transportation system, are undergoing extensive wind tunnel testing at NASA Langley Research Center in Hampton, Va.

Several models are being tested in a half-dozen tunnels at Langley as part of a joint NASA-Lockheed Martin effort to develop the technologies for a space transportation system that would provide faster and cheaper access to space than current systems. The technology will first be tested in a suborbital vehicle known as the X-33.

The wind tunnel tests are providing information about how the vehicle's design performs aerodynamically over a range of speeds from takeoff to hypersonic flight approaching a Mach number of 15 (15 times the speed of sound).

In the early phases of the program, screening tests were conducted in the Langley 22-Inch Mach 20 Helium Tunnel. The helium tunnel was chosen for initial testing because it operates at room temperatures which allows testing to be performed on six-inch plastic models that can be made quickly and inexpensively.

"These tests measure the high Mach number aerodynamics that must be understood to design an aerospace vehicle for flight in this speed regime," said Bill Scallion, an engineer in the Aerothermodynamics Branch who heads aerodynamic testing for the X-33.

An aluminum and stainless steel model of the X-33 - about 15 inches long by 15 inches wide - was also recently tested in the Low Turbulence Pressure Tunnel (LTPT) at Langley.

"These subsonic tests were conducted at the speed of Mach 0.25. Aerodynamic force and moment testing in this tunnel lasted about one week," said Kelly Murphy of the Aerothermodynamics Branch.

The same model is now being tested in Langley's 16-Foot Transonic Tunnel until mid-April 1997. The 16-foot tunnel runs at speeds near the speed of sound. Following these tests, the model will be moved to Langley's Unitary Wind Tunnel for supersonic (Mach 1.5 to 4.5) testing from mid-April to early May.

Additional tunnel testing of X-33 models is scheduled through June in tunnels in the Hypersonic Facilities Complex, and from mid-June to mid-July in the Langley 14- by 22-Foot Subsonic Tunnel.

Marshall Space Flight Center in Huntsville, Ala., is the lead NASA center for managing the Reusable Launch Vehicle (RLV) program, an industry-led effort that NASA Administrator Daniel S. Goldin has declared the agency's highest priority new program.

The RLV Technology Program is a partnership among NASA, the Air Force, and private industry to develop world leadership in low-cost space transportation. The goal of the program is to develop technologies and new operational concepts that can radically reduce the cost of access to space.

The RLV program also hopes to speed the commercialization of space and improve U.S. economic competitiveness by making access to space as routine and reliable as today's airline industry, while reducing costs and enhancing safety and reliability.

The RLV program combines ground and flight demonstrations. The use of experimental flight vehicles like the X-33 will help verify vehicle systems performance in a realistic environment.