Use of arc-jet hypersonic blunted wedge flows for evaluating performance of Orbiter TPS

Arc-jet tests at NASA/JSC have been conducted recently to evaluate the performance of the Orbiter Thermal Protection System (TPS) on three critical areas of the side and top of the Orbiter fuselage: (1) cargo bay door, (2) crew access door, and (3) LRSI/FRSI joint regions. Test articles corresponding to these three areas on the Orbiter were mounted in an arc-jet test chamber in a blunted-wedge holder and exposed to hypersonic flow at various angles of attack. The effects of flow direction, heating load, and overtemperature were investigated. In addition, the reuse capability of the TPS materials was evaluated, along with the protection of the pressure seals within the test articles. Thermal match model predictions correlated well with primary structure thermocouple data. Heating rate and pressure predictions based on a nonequilibrium flow field computer program showed good agreement with arc-jet test data and existing hypersonic flow theories.