NASA Finds Root Cause Of Orion Heat Shield Charring

NASA says it has determined why its Orion spacecraft returned from its 25-day Artemis I flight test around the Moon with unexpected charring in its heat shield.

Agency officials, however, declined to release its findings, pending ongoing internal discussions about next steps.

The finding was disclosed at two industry meetings on Oct. 28, with NASA’s Lori Glaze, acting deputy associate administrator for Explorations Systems Development Mission Directorate, speaking at NASA’s Lunar Exploration Analysis Group, and Lakiesha Hawkins, assistant deputy associate administrator for the Moon to Mars office, later addressing a question at the opening session of the American Astronautical Society’s 2024 von Braun Space Exploration Symposium.

“We have gotten to a root cause,” Hawkins said. “We are having conversations within the agency to make sure that we have a good understanding of not only what’s going on with the heat shield, but also next steps and how that actually applies to the course that we take for Artemis II.

“We’ll be in a position to be able to share where we are with that hopefully before the end of the year,” Hawkins said.

Among the issues uncovered by the Nov. 16-Dec. 11 Artemis I flight test was unanticipated charring of the Orion capsule’s ablative Avcoat heat shield material. The 16.5-ft.-dia. shield was designed to protect the spacecraft during atmospheric reentry speeds of up to about 25,000 mph and temperatures of nearly 5,000F.

Sensors in the Artemis I Orion capsule showed thermal conditions still met crew safety constraints during atmospheric reentry, but the heat shield’s performance did not match preflight thermal and mechanical computer models.

NASA in January delayed the follow-on crewed Artemis II mission to September 2025 from November 2024 in part to better understand the issue with the Orion heat shield.

Glaze said engineers have demonstrated and replicated the heat shield charring with tests at the Arc Jet Complex at NASA’s Ames Research Center. “We’re assessing what is the appropriate approach for Artemis II regarding the heat shield,” she said, noting that construction of the shield is complete.

Additional testing is underway, she added. “We expect that to be done by the end of November, and then we anticipate discussions with the administrator, who will make the final decision on how to proceed.”

Artemis II is planned to be a 10-day mission during which four astronauts—three from NASA and one from the Canadian Space Agency—fly around the Moon in an Orion capsule and return to Earth. That is to be followed about one year later by Artemis III, which features a landing on the south pole of the Moon.