On June 2, 2001, the first flight test of the approximately 50 ft-long Hyper-X Launch Vehicle stack, which included the 12ft X-43A hypersonic scramjet research vehicle attached to a modified stage one Pegasus rocket booster, was to accelerate to Mach 7and release the X-43A at an altitude of 95,000 feet. From that point, the X-43A would have fired its scramjet for 10 seconds, traveling 14 miles under its own power on a preprogrammed flight path before impacting 400 miles further out in the Pacific Ocean. Unfortunately, the modified booster rocket failed at transonic conditions and had to be destroyed early in flight.

As a result, the X-43A research vehicle was not tested, because it never reached test conditions. Numerous actions have been taken to correct the problems identified during the mishap investigation and to further reduce risk for the next flight. The next flight sucessfully flew to Mach 7 on March 27, 2004, and again a second time to Mach 10 on November 16, 2004.

Mr. Farhad Ghaffari and Ms. Melissa Carter at NASA Langley Research Center were instrumental in providing the primary computational aerodynamic support to the mishap investigation. Over 60 Navier-Stokes solutions were computed with TetrUSS, providing critical aerodynamic load estimates and understanding.

Dr. Paresh C. Parikh, NASA Langley and Dr. Sasan Armand, Analytical Mechanics Associates, supported the Return to Flight effort by generating over 100 Navier-Stokes solutions on 32 grids for the full stack geometry with various control surface configurations. This work is reported in AIAA Paper 2004-5385.

Mr. Ed Parlette of ViGYAN, Inc. generated more than 40 grids of the full X-43A/HyperX stack geometry for the efforts.

More information on the X-43A (Hyper-X) program can be found at the Hyper-X Home Page.

(Quote used by permission)