AEROHEATING FLIGHT INSTRUMENTATION

THE CURRENT INVENTORY OF INSTRUMENTS TO MEASURE AERODYNAMIC HEATING DURING SUPERSONIC AND HYPERSONIC FLIGHT OF A SPACE VEHICLE IS EXTREMELY LIMITED. THE EVALUATION OF MUCH OF THEHEAT TRANSFER DATA MEASURED BY SCHMIDT - BOELTER AND GORDON CALORIMETERS HAS POINTED OUT THE LARGE ERRORS INHERENT TO THESE INSTRUMENTS DUE TO A PHENOMENA CALLED THE TEMPERATURE MISMATCH ERROR. THIS ERROR IS BASICALLY CAUSED BY LARGE SURFACE TEMPERATURE GRADIENTS BETWEEN THE CALORIMETER FACE AND THE UPSTREAM SURFACE. AN EMPIRICAL METHOD DEVELOPED IN 1961 TO ESTIMATE THIS ERROR FOR TWO DIMENSIONAL UNDISTURBED FLOW WAS USED TO CORRECT THE SHUTTLE FLIGHT DATA. THIS METHOD PROVIDES, AT BEST, AN ESTIMATE FOR CORRECTING THE FLIGHT DATA ESPECIALLY IN THREE DIMENSIONAL AND HIGHLY DISTURBED FLOW. THE OBJECTIVE OF THE PHASE I STUDY IS TO DEVELOP AND ANALYZE CONCEPTUAL DESIGNS THAT ELIMINATE THE TEMPERATURE MISMATCH ERROR. THE BEST CONCEPT WOULD THENBE DESIGNED, FABRICATED, TESTED AND VERIFIED DURING THE PHASE II STUDY.