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?
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In this document (thats also linked in the main article) you find a great explanation to your question.
The original design used a honeycomb structure, because problems with cracking and gas permeability had been known (in the 1960s).
On the other hand it would be more labor intensive to build it in that way.
https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz...
Arguably, the goal isnt to go to the moon. Thats the mission, but the goal is to improve our capabilities of space travel. Improving our understanding and engineering of heat shields is one such case
The very first Apollo attempt killed three astronauts. We would need something different now because the cold-war-crazy days are behind us, and we don't push ahead with missions that might end up in casualties.
Related - what does SpaceX Dragon use for heat shield material and can it be used on Orion?
Or Apollo development was a massive boondoggle that would never work and a small subset of those involved faked it to avoid being fired or going to prison. I know that directors of multibillion dollar projects lying to save their own skin is unheard of, but hear me out.
Artemis, launching on April Fools Day, seems like a joke waiting to happen.
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.