Description: To address NASA's need for in situ sensor systems for use on rigid and/or flexible ablative Thermal Protection System (TPS) materials, Physical Optics Corporation (POC) proposes to develop a novel Embedded Multifunctional Optical Sensor (EMOS) system providing accurate in situ measurement of multiple thermal protection system (TPS) structural, aerothermal, and aerodynamic response parameters including temperature, heat flux, and pressure. The EMOS is based on use of novel materials for high-temperature operation and uniquely designed fiber optic microsensors. The EMOS system is capable of simultaneously measuring multiple TPS response parameters (e.g., pressure, temperature, and heat flux) using a suite of miniature (diameter 1500 degrees C and measurement errors within 0.4% for temperature sensors, 0.2% for pressure sensors, and 20% for heat flux measurement. In Phase I POC will demonstrate the feasibility of EMOS for in-situ measurement of TPS responses in an aerothermal environment by fabricating and testing a technology readiness level (TRL)-4 prototype, with the goal of achieving TRL-6 by the end of Phase II.

Benefits: The proposed EMOS will provide for NASA a distributed and embedded in situ system for measurement of TPS responses in aerothermal and aerodynamic environments. The proposed EMOS sensor system will provide better traceability from the modeling and design tools to actual performance, because the resultant EMOS sensor data can lead to higher-fidelity design tools, improved risk quantification, decreased heat shield mass, and increases in direct payload. For specific NASA applications, EMOS microsensors can be applied to different types of ablative materials used for TPS including, but not limited to PICA, PICA-X, SIRCA, Superlight Ablator (SLA), and Avcoat, and those under development for planetary aerocapture and entry as well as return to Earth.

Military applications of the EMOS system will include health monitoring of military aircraft components. The military will benefit from this technology by incorporating EMOS into the engine and drivetrain components of rotorcraft to monitor, in situ and in real time, potential component failure, to reduce the amount of inspection and testing required, and increase reliability and mission availability. Commercial applications include industrial control and heavy equipment used in construction and mining operations, health monitoring of commercial aircraft engines, drivetrain systems, and utility systems. An immediate application of the EMOS system will be monitoring coal-fired power plants, natural-gas-based power plants, geothermal plants, as well as other power-generation facilities throughout the nation. This sensor suite can be used directly in critical high-temperature power plant components including superheater and reheater pendants for in-situ real-time condition monitoring.