Researchers are peering inside spacecraft heat shields during extreme heat conditions using X-ray micro-CT imaging and AI. A decade-long partnership between NASA and the Advanced Light Source at Lawrence Berkeley National Laboratory has captured real-time structural breakdown at temperatures up to 1,652 degrees Fahrenheit.
Real-Time Micro-CT Imaging Captures Ablation Under Reentry Conditions
When a spacecraft reenters Earth’s atmosphere at hypersonic velocities, its protective heat shield faces extreme temperatures beyond 3,000 degrees Fahrenheit. Survival depends on a controlled process called ablation, where specialized materials sacrifice their outer layers to absorb heat and shield the vehicle and crew inside. Designing these thermal protection systems has long forced engineers to rely on pre- and post-test observations because watching the microscopic breakdown in real time proved exceptionally difficult.
To clear this hurdle, researchers from the University of Illinois Urbana-Champaign and NASA partnered with the Advanced Light Source (ALS) at the Department of Energy’s Lawrence Berkeley National Laboratory. By deploying an in situ X-ray micro-computed tomography technique known as micro-CT, the team pushed experimental boundaries by heating sample materials to 1,652 degrees Fahrenheit—the top of the temperature range where these materials begin to decompose.
“Directly observing how heat shield materials degrade during heating with this technique has been transformative for atmospheric entry research since it gives us unique insights and helps us visualize the internal structural changes that drive ablation as it occurs.”
Vishnu Oruganti, researcher at NASA’s Johnson Space Center
That decade-long collaboration has yielded high-detail, time-lapse 3D imagery of superlight ablators used on the backshells of NASA spacecraft. Oruganti noted that nearly every major NASA ablative heat shield material has been studied at the facility, including those relevant to Artemis and Mars entry missions.
AI-Driven Super-Resolution Unlocks Microscopic Decompositions in SLA-220 and SLA-561V
Training the AI on those images enhanced the entire experimental sequence into a comprehensive high-resolution record.
- SLA-561V: Studied as a commercial ablator used in spacecraft backshells with a specific composition.
- SLA-220: Studied as a commercial ablator used in spacecraft backshells with a different composition than SLA-561V.
Tracking these multiphase chemical decompositions and porosity shifts provides critical data for validating predictive models. ALS scientist Liz Clark noted that after the first Artemis mission, where heat shields didn’t perform as NASA expected from computational methods, teams used the facility to examine materials from these shields and better understand how internal structures evolve over time.
Asymmetric Thermal Coatings and Future Spacecraft Safety
Beyond studying ablative degradation, researchers are designing novel exterior coatings to manage intense solar radiation and atmospheric entry heat. USC engineers Michelle Povinelli and Jayakanth Ravichandran tackled the problem of radiative heat flow in space, where standard cooling methods like fans or evaporation fail due to a lack of surrounding air.
Published in Optical Materials Express, their research details an unpatterned planar layer system pairing calcium zirconate and strontium ruthenate.
By combining real-time micro-CT insights with advanced materials engineering, researchers are systematically closing the gap between computational models and the reality of space flight.