Health Monitoring For Thermal Protection Systems On Reusable Launch Vehicles

When a Reusable Launch Vehicle (RLV) travels through the atmosphere there should be strong aeroheating around it, so a Thermal Protection System (TPS) would be used to protect the vehicle structures from aerothermal ablation. However, the TPS structure may fail more frequently than normal vehicle structures because of the severe environment and load conditions, while a TPS failure can even lead to a catastrophic breakdown of vehicle structures. To keep the RLV safe, the TPS must be monitored realtime.Based on an analysis of the TPS structure and some historical faults, typical fault modes are summarized for the TPS, four in two categories of which are chosen for detailed analysis. To learn the heat transfer inside a ceramic TPS tile and the modal parameter of a metallic TPS panel two finite element models are built, and computation made with them indicates that temperature monitoring and frequency monitoring of the TPS structure should be effectual for fault detection.A TPS health monitoring program is conceived after the study of TPS faults, which covers both rise-and-reentry monitor and in-orbit examination, and employs both large scale temperature filed lookout and special check. Issues as examination locations and parameters and fault detect methods are discussed. Principle for cooperation between on-line monitoring and ground-based supervision are discussed as well.Finally, a virtual-instrument-based demonstration and verification software system is developed, with which the mail process for TPS health monitoring is implemented and found to be successful.