Structural Health Monitoring Tests May Aid Access to Space Published Dec. 4, 2007 By Air Vehicles Directorate AFRL/RB WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- AFRL recently tested a Structural Health Monitoring (SHM) system that may help improve rapid access to space. The test activity leaves researchers just one step away from developing an Operationally Responsive Space (ORS) vehicle, a craft capable of launching quickly, returning to earth, and launching again within a few hours. The SHM tests involved a thermal protection system (TPS) test panel equipped with thermocouples and piezoelectric, acoustic emissions, and fiber-optic sensors. The various sensors monitored the structural integrity of the TPS panel as it endured simulated space launch conditions, including temperatures up to 2100°F and acoustic loads up to 165 dB. The research team conducted the tests in AFRL's Combined-Environment Acoustic Chamber, the only facility capable of simulating such extreme environments. The test results showed that all sensors not only survived the harsh environment to which they were subjected, but accurately detected the damage to the TPS panel. By monitoring and reporting any potential structural damage incurred by the TPS during launch, spaceflight, and reentry, the SHM system could potentially reduce turnaround time for vehicles such as the space shuttle and other reentry aircraft. While SHM can likely benefit the ORS program, it can also be incorporated into high-speed vehicles such as the F-16 to help monitor in-flight damage and assist anticipation of emerging structural problems.