Minimally Intrusive Embedded Sensors for High Mass Thermal Protection Systems, Year 2

Goal: To develop a MEMS-based integrated recession/temperature sensors that can be non-intrusively embedded and distributed across a large area of the TPS during manufacture. Capability Need/Knowledge Gap: This proposal aligns with STMD-Strategic Thrust: Land – Landing Heavy Payloads. The NASA Mars 2030 mission roadmap calls for “Miniaturized, Micro Electro Mechanical Systems (MEMS)- Based Sensors for Entry Vehicles” to measure TPS recession rate and temperature during vehicle entry. Many elements of EDL cannot be replicated in ground test facilities, either due to Earth-based limitations (gravity, gas composition, etc.) or due to practicalities achieving the appropriate high energy flows. Hence, heavy dependence is placed on modeling and simulation. However, the uncertainties that exist in these simulations make the need for experimental validation more critical. State-of-the-Art/Knowledge: The Mars Science Laboratory Entry Descent and Landing Instrumentation-2 (MEDLI-2) is considered the SoA instrumentation for the TPS. It uses TPS plugs with embedded thermocouples to measure in-depth thermal response from which recession rate could be inferred. Key Technical Challenges: Applying the lessons learned from the FY18 CIF effort to form the basis of this technical approach. Approach/Research Plan: (1) Design optimization based on lessons learned and fabricate recession rate and temperature sensors (GRC); (2) Embed sensors in selected Avcoat and PICA samples (GRC and ARC); and, (3) Arc-jet testing (Innoveering, LaRC, and ARC). The MEMS recession sensor is based on derivative capacitive sensing, whereby the capacitance decreases as its tip undergoes ablation with the TPS material. The concept of minimally intrusive recession sensors was demonstrated during the FY18 CIF effort, with promising results. While the recession rate was not fully resolved due to premature failure of the sensors, the obtained average weight loss was in good agreement with previously published work. A more optimized adjustment of the capacitance-voltage converter would be implemented so that the reference voltage properly set. The use of the silver paste to attach the external wires to the sensor bond pad would be replaced with direct Au-Au bonding to eliminate temperature induced detachment. Next Step: Further technology maturation process would commence with discussion with STMD and Ames at the end of Q4.

There are several funded extreme environment future missions with ablative heat shields: Orion EM-2 Artemis; Mars Sample Return; and New Frontiers Dragonfly to Titan. It is imperative to sufficiently monitor the health of the TPS by way of large area coverage of the surface with miniature, low weight, and minimally intrusive instrumentation.

This is a mature technology (TRL 7+) — the realistic path in is usually NASA's Technology Transfer Program: licensing an existing NASA patent, or a Space Act Agreement to use NASA facilities/expertise directly. NASA also runs a startup licensing program with no upfront fee for companies formed to commercialize a specific NASA technology.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.