Real-Time Ablation Recession Rate Sensor System for Advanced Reentry Vehicles

摘要

The development of a new sensor system for in-situ, real-time measurements of recession rate of heat shield ablative materials is described. The sensor utilizes a focused ultrasound approach to non-intrusively detect the ablative material's surface loss while simultaneously correcting for acoustic velocity dependencies on temperature. The latter correction is done via a closed loop feedback approach. The multi-source focusing approach is atypical of current ultrasound based sensors used for ablation recession rate measurement, which require a-priori knowledge of temperature distribution within the ablative to yield accurate data on recession rate. The paper describes the operating principles of the sensor and reports on results obtained in testing the breadboard sensor system in a relevant environment at ATK GASL's POET facility.