X-43A Flush Airdata Sensing System Flight Test Results

The National Aeronautics and Space Administration (NASA) has flight-tested a flush airdata sensing (FADS) system on the Hyper-X Research Vehicle (X-43A) at hypersonic speeds during the course of two successful flights. For this series of tests, the FADS system was calibrated to operate between Mach 3 and Mach 8, and flight test data was collected between Mach 1 and Mach 10. The FADS system acquired pressure data from surfacemounted ports and generated a real-time angle-of-attack (! ) estimate on board the X-43A. The collected data were primarily intended to evaluate the FADS system performance, and the estimated ! was used by the flight control algorithms on the X-43A for only a portion of the first successful flight. This paper provides an overview of the FADS system and ! estimation algorithms, presents the in-flight ! estimation algorithm performance, and provides comparisons to wind tunnel results and theory. Results indicate that the FADS system adequately estimated the ! of the vehicle during the hypersonic portions of the two flights.