Infrared sensing aeroheating flight experiment: STS-96 flight results

Major elements of an experiment called the infrared sensing aeroheating flight experiment are discussed. The primary experimental goal is to provide reentry global temperature images from infrared measurements. These measurements are used to define the characteristics of hypersonic boundary-layer transition during flight. Specifically, the experiment is to identify, monitor, and quantify hypersonic boundary-layer windward surface transition of the X-33 vehicle during flight. In addition, the flight data will serve as a calibration and validation of current boundary-layer transition prediction techniques; provide benchmark laminar, transitional, and fully turbulent global aeroheating data to validate existing wind-tunnel and computational results; and advance aeroheating technology. Shuttle Orbiter data from STS-96 are used to validate the data acquisition, and data reduction to global temperatures, to mitigate the experiment risks before the maiden flight of the X-33, is discussed. STS-96 reentry midwave (3-5 mum) infrared data were collected at the Ballistic Missile Defense Organization/Innovative Sciences and Technology Experimentation Facility site at NASA Kennedy Space Center and subsequently mapped into global temperature contours using ground calibrations only. A series of image mapping techniques have been developed to compare each frame of infrared data with thermocouple data collected during the flight. Comparisons of the ground calibrated global temperature images with the corresponding thermocouple data are discussed. The differences are shown to be generally less than about 5%, which is comparable to the expected accuracy of both types of aeroheating measurements.