Wireless Temperature Sensors for Health Monitoring of Aerospace Thermal Protection Systems

Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and industry partners to develop "wireless" devices that can be embedded in the thermal protection system to monitor temperature or other quantities of interest. These devices are sensors integrated with radio-frequency identification microchips to enable noncontact communication of sensor data to an external reader that may be a hand-held scanner or a large portal through which the entire vehicle may be passed. Both passive and active (battery assisted) prototype devices have been developed. The passive device uses a thermal fuse to indicate the occurrence of excessive temperature. The active device uses a thermocouple to measure temperature history.