Simulation Software is Key to Orion’s Heat-Shield Success

Tecplot 360 EX data visualization and analysis software
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NASA chose Tecplot 360 EX for use in the design of the heat shield for the Orion spacecraft. Orion’s heat shield, a protective blanket built with high-tech fibers and ceramics, is crucial to mission success. The outer layer of the heat shield is designed to burn away as it heats up during re-entry into the atmosphere, thus maintaining the integrity of the inner layer and helping to ensure the survivability of the spacecraft.

Simulation of roll jets interacting with the incoming flow using DPLR with an SST turbulence model. Temperature contours of the plume and on the vehicle’s surface show potential heating augmentation on the aftbody of the Orion MPCV capsule. (NASA)

To predict temperature and airflow around the heat shield during re-entry, a team of engineers analyzed heat-shield materials in NASA Ames’ Arc Jet wind-tunnel, and then compared the results with those generated by CFD (computational fluid dynamics) simulations. They then used Tecplot 360 EX as a post-processor to analyze, visualize, and understand the CFD results.

The Tecplot software helped engineers visualize the simulations generated by two NASA-developed CFD solvers: DPLR, or Data Parallel Line Relaxation; and LAURA, or Langley Aerothermodynamic Upwind Relaxation Algorithm. The DPLR and LAURA tools simulate the physics of the extreme heat generated when an object enters Earth’s atmosphere.

The NASA team ran about 2,000 DPLR and LAURA simulations and analyzed those simulations with the Tecplot software. The simulations tell NASA how hot the heat shield surface will get when entering the atmosphere based on the known physics of friction of the molecules in the atmosphere flowing over the heat shield. The team knows from other testing at what temperature the heat shield will melt, so if the simulations show the temperature staying below that mark, they can safely predict that Orion will survive that part of the re-entry process.

NASA conducted the first test flight of the Orion Program late last year. If all goes according to plan, the Orion spacecraft will put humans on an asteroid by 2025, and on Mars in the 2030s.

Unmanned for its first test flight, Orion was designed and constructed to travel farther into space than any other spacecraft intended to carry humans, and through temperatures twice as hot as molten lava. The sole purpose of the flight was to test Orion’s critical systems under real flight conditions. The next unmanned test flight of Orion is expected in late 2017 or early 2018.

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