- Through a decade-long partnership between the ALS and NASA, researchers are studying how heat shield materials called superlight ablators degrade, informing NASA spacecraft design.
- Research at the ALS offered a new detailed picture of this hidden process, one that has meaningfully improved how engineers model and design heat shields for space missions such as the recent Artemis missions.
- By combining X-ray scans with AI-trained models, the team successfully captured the microscopic breakdown of these materials in real time.
When a spacecraft reenters Earth’s atmosphere at hypersonic velocities, its protective heat shield faces the most extreme conditions, including temperatures beyond 3,000 degrees Fahrenheit. To survive, the shield relies on specialized materials that absorb the heat as it degrades away in a controlled process called ablation, sacrificing the outer layers of the heat shield to protect the vehicle and crew within.
Designing those materials requires understanding exactly how they degrade — but watching that process at the microscopic level, in enough detail to capture necessary information on the materials, has been a challenge, forcing engineers to rely on pre- and post-test observations to develop computational models.
At the Advanced Light Source (ALS) at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), researchers found a way to watch ablation in real time.
Using a sample environment on an X-ray tomography instrument that independently controls temperature, pressure, and gas mixture, recreating realistic, evolving reentry conditions. Findings from a recent study carried out in part at the ALS offer detailed, time-lapse, 3D images of this process, improving how engineers model and design thermal protection systems for space missions, including NASA’s recent Artemis missions.
“Nearly every major NASA ablative heat shield material has been studied with this technique at the Advanced Light Source, including those relevant to the Artemis and Mars entry missions.” – Vishnu Oruganti, user of the ALS.
“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,” said Vishnu Oruganti, who was a postdoctoral fellow at the University of Illinois Urbana-Champaign at the time of the study and is now a researcher at NASA’s Johnson Space Center in Houston. “Nearly every major NASA ablative heat shield material has been studied with this technique at the Advanced Light Source, including those relevant to the Artemis and Mars entry missions.”
Read more on the LBL website
Image: A heat shield removed from NASA’s Orion spacecraft and inspected following the Artemis I test flight
Credit: NASA