Reliable Thermal Protection Systems for Planetary Missions
To protect a spacecraft, crew, and payload during atmospheric entry, vehicles are equipped with a thermal protection system (TPS), which includes the heat shield, back shell, and supporting structure. Since TPS is essential to many of NASA’s highest priority space exploration missions, the research team at the University of Kentucky is aiming to improve the reliability of computational modeling of these systems during the design phase of a vehicle. A significant limitation with current capabilities is that the uncertainties—which stem from material variability caused during manufacturing, availability of raw materials, and other mitigating circumstances—are so large that it is not always possible to provide accurate analyses in time to meet mission milestones. The Kentucky team has developed new TPS material modeling methods using a multi-scale approach, where the smallest scale directly informs the largest ones, allowing a holistic evaluation of the TPS. In this approach, detailed atomic-scale information is first fed to the micro-scale, then the scatter at the micro-scale is captured through probability distribution functions that are fed to the macro-scale, where a stochastic modeling approach is used to predict TPS behavior. The stochastic approach—where a random probability distribution or pattern is used—provides nominal behavior and helps capture material response caused by variabilities and other unexpected scenarios, allowing researchers across NASA a pathway for robust quantification of TPS reliability.
The computing environment at the NASA Advanced Supercomputing facility is amazing. Once I set my automated workflow, the computations are done at breakneck speed. I love it.
Luis Chacon,
Graduate student researcher at the University of Kentucky
Quick Facts
- The new model developed to predict material behavior using real material microstructures is one of the most complete picture in TPS design. To predict TPS behavior, the team runs thousands of simulations over material microstructures to compute material properties and performs aero-thermal-chemical-structural simulations on the microstructure to quantify TPS reliability. Most of the simulations are run on the Pleiades supercomputer at the NASA Advanced Supercomputing (NAS) facility at NASA’s Ames Research Center, using 1.2 million CPU core-hours, with a current run rate of 200,000 CPU hours every month.
- The team quantified the potential variabilities in TPS materials arising from inconsistencies in manufacturing. Even if material billets—solid bars or rods—are manufactured through different processes or contain defects, the models can accurately predict TPS performance during atmospheric entry.
- The ability to accurately model TPS performance regardless of manufacturing processes will significantly reduce lead time in qualifying TPS materials for planetary entry missions.
- The researchers are working to develop an optimized workflow to select and qualify an optimal TPS material architecture for a given mission. Therefore, instead of choosing a mission’s vehicle design based on existing TPS technology, they want to be able design a TPS to meet the unique needs of a planetary mission.
Researchers
- Savio Poovathingal, University of Kentucky Please enable Javascript to see email address.
- Alexandre Martin, University of Kentucky Please enable Javascript to see email address.