Description: Low-profile, embedded sensors are proposed for condition monitoring and health management (HM) of thermal protection systems. The sensors will be fabricated using a high precision Direct Write (DW) process based upon thermal spray, affording them the advantages of high temperature tolerance, reproducibility, durability, and materials compatibility. In-situ sensing of temperature, heat flux, and surface recession will be demonstrated per the performance requirements specified for thermal protection systems. Relevant testing configurations will employ high temperature furnaces and flame rigs, specifically to validate sensor functionality, accuracy, and survivability. Sensor compatibility with TPS representative materials will also be considered to ensure seamless integration for rapid technology deployment. Having demonstrated their diagnostic capabilities, combining the sensors with DAQ and HM infrastructures would form the cornerstone of a potential Phase II, continuing application-specific development while expanding to address HM integration issues.

Benefits: Harsh environment sensors are in high demand, spanning a range of industries including power generation, commercial and military aviation, aerospace structures and transportation, and diagnostics for space systems. DoD applications for harsh environment diagnostic sensors are primarily aerospace and rotorcraft, specifically including instrumentation for short term testing at the component-level and long-term monitoring/prognostics as part of a comprehensive health management solution. Most notably, the demand is driven by gas turbine engine designers for industrial power generation equipment (gas turbine, steam, boilers), aero propulsion systems (gas turbine and hypersonic engine components), aerospace, chemical processing, oil & gas, and other commercial applications. Diagnostics are also sought for air-breathing scramjets and other hypersonic vehicles (e.g. sounding rockets) to enable integrated condition monitoring and advanced prognostic capabilities.

NASA has a need for integrated vehicle health management capabilities for a number of space structures and systems, for which this development effort targets diagnostics development for ablative thermal protection systems. MesoScribe's focus is the sensing component of health and condition monitoring, providing innovative, deployable solutions for measuring temperature, heat flux, and surface or coating degradation. Such information can be coupled with performance models to support new designs and enhance system reliability. More generally, applications for embedded sensors include measuring component temperature; insulation and heat shield integrity; blow-by detection; and in-situ heat flux.