alt Hacker NewsSomeone please answer my obvious question. We sent successful missions to the moon sixty years ago. What heat shield material was used for the Apollo capsules, and why would we need something different now? Are the Artemis mission parameters totally different in a way that requires a new design? Or was Apollo incredibly dangerous and we got lucky they didn’t all fail catastrophically? The article mentions Orion is much heavier than the Apollo capsules, does that really require a totally novel heat shield that takes $billions to develop?
The Apollo command module used Avcoat, the same material as Orion. But there are two key differences:
1. The application method is different. Apollo applied it to a metal honeycomb structure with very small cells, while Orion uses blocks of the material. (NASA tried the honeycomb approach for Orion, but it was too labor-intensive).
2. Orion is much bigger and heavier than the Apollo command module. The informal consensus is that Apollo may have been at the upper size limit for using Avcoat.