2021's Artemis I mission declared successful, but Orion's heat shield ablated differently than expected.

NASA declared Artemis I mission successful in 2021, but an issue with Orion's heat shield didn't meet expectations. As the capsule re-entered Earth's atmosphere, the heat shield ablated differently than predicted by computer models, with more charred material exiting unevenly. Despite the heat shield being made of Avcoat, designed to burn off during re-entry, NASA still doesn't understand the root cause.