Infrared sensing aeroheating flight experiment: STS-96 flight results

Major elements of an experiment called the infrared sensing aeroheating fli ght experiment are discussed. The primary experimental goal is to provide r eentry global temperature images from infrared measurements. These measurem ents are used to define the characteristics of hypersonic boundary-layer tr ansition during flight. Specifically, the experiment is to identify, monito r, and quantify hypersonic boundary-layer windward surface transition of th e 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 gl obal aeroheating data to validate existing wind-tunnel and computational re sults; and advance aeroheating technology. Shuttle Orbiter data from STS-96 are used to validate the data acquisition, and data reduction to global te mperatures, to mitigate the experiment risks before the maiden flight of th e X-33, is discussed. STS-96 reentry midwave (3-5 mum) infrared data were c ollected at the Ballistic Missile Defense Organization/Innovative Sciences and Technology Experimentation Facility site at NASA Kennedy Space Center a nd subsequently mapped into global temperature contours using ground calibr ations only. A series of image mapping techniques have been developed to co mpare each frame of infrared data with thermocouple data collected during t he flight. Comparisons of the ground calibrated global temperature images w ith the corresponding thermocouple data are discussed. The differences are shown to be generally less than about 5%, which is comparable to the expect ed accuracy of both types of aeroheating measurements.