Space.com by Leonard David 4/18/2024
The landmark 2022 moon mission was a success, but questions remain about how Orion's heat shield performed.Earlier this year, NASA announced it had delayed until September 2025 the crewed Artemis 2 swingby of the moon, a practice run to prepare for 2026's Artemis 3 mission, which will land astronauts near the lunar south pole.
One reason cited for the 10-month delay was getting to the bottom of reentry heat shield data from Artemis 1, which sent an uncrewed Orion capsule to lunar orbit and back.
Engineers have been analyzing data from that shakeout cruise, which began with a launch by NASA's Space Launch System megarocket on Nov. 16, 2022.
The 25-day Artemis 1 mission ended on Dec. 11, 2022, with the Orion capsule splashing down under parachutes in the Pacific Ocean off Baja California.
Blistering reentryOrion's heat shield took on the 25,000 mph (40,000 kph) reentry speed that day, protecting the capsule ably. But soon thereafter, NASA and contractors began wrestling with the discovery that Orion's ablative heat shield wore away differently than predicted.
Some areas of expected charred material ablated away in a manner not forecast by computer modeling and ground testing. Also, there was slightly more liberation of the charred material during reentry than anticipated.
Orion's heat shield features the same ablative material, called Avcoat, used during the Apollo program in the late 1960s and early 1970s. However, the building process for the heat shield was changed from the Apollo-era method.
Vintage ApolloWhile Avcoat is vintage Apollo, the production process for Orion's 21st-century thermal protection system was altered.
More:
https://www.space.com/nasa-investigate-orion-heat-shield-artemis-1-mission
