Description: The Phase I project will develop a suite of diagnostic sensors using Direct Write technology to measure temperature, surface recession depth, and heat flux of an ablative thermal protection system (TPS) in real time, which can be integrated to support TPS evaluation and in-situ diagnostics during planetary entry. Standalone heat flux sensors and those fabricated by direct deposition will be developed and demonstrated for integration within TPS materials for use in extreme re-entry conditions. The intent is to use the sensors for real time heat flux measurements to validate new materials and systems, as well as for flight structures where space and accessibility are limited. Methods for incorporating thermocouples, heat flux and recession sensors using Direct Write technology will be developed to provide accurate sensing capabilities. Notably, recession tolerant heat flux sensors will be designed and fabricated to demonstrate feasibility of this new heat flux sensor technology and subsequent instrumentation capability for TPS.

Benefits: NASA has communicated a need for advanced TPS sensing to improve laboratory performance evaluation of new TPS materials as well as in-situ monitoring for manned and unmanned missions. Testing and evaluation of new TPS materials represents a significant activity in the planning of all missions. Typically, the TPS requirements are fairly well identified with respect to heat flux profile, duration, atmosphere, etc. based upon the specific mission. However, ruggedized sensors for monitoring heat flux in-situ are not yet available for TPS validation or fielding. The Orion capsule, being developed by NASA under the MPCV (Multi-Purpose Crew Vehicle) program, calls for a number of TPS sensors where real time heat flux data would be invaluable. Challenging opportunities exist at JPL in developing TPS systems for unmanned sample return missions from both a Near Earth Object (NEO) and Mars. The competing requirements for low mission weight and increased TPS performance due to increased thermal loads from higher re-entry speeds results in a need for improved sensors for TPS development.

Opportunities for sensor integration onto manned and unmanned vehicles not only exist within NASA, but are becoming more prevalent in the commercial sector including space travel as well as other areas. Sensors are needed to monitor the health and condition of the heat shield during re-entry for the COTS and ccDEV programs. Outside of space applications, harsh environment sensors are in high demand, spanning a range of industries including power generation, commercial and military turbo-machinery, aerospace structures, and solar. DoD applications for harsh environment diagnostic sensors are primarily aerospace and rotorcraft, specifically seeking instrumentation for short term testing at the component-level and long-term monitoring/prognostics as part of a comprehensive health management solution. Application 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.