From the prompt it seems evident the envisioned user doesn't have an interest in designing the motor themselves, so why not simply buy a stock motor?

Stop it, you tease. I'm getting a little tingly

Are there already skills around modelling, simulation and post-processing? Any pointers?

I’m not convinced at all that the model won’t just get stuck in a loop where it doesn’t understand how to fix the broken rocket. I see similar failure modes in far simpler projects strictly confined to coding. This feels closer to “make me a profitable business, make no mistakes” than to a simple coding project.

You almost certainly do not want an LLM to do that. Leap71 actually has computational models generating functional rocket engines that way. You could absolutely wrap a tool like that in a shell and handle control with an LLM and not need anywhere near the tokens.

Thats the thing - these models see and predict tokens. For any real engineering you get more bang for your buck using math.

Verifying how the model works against the real world is the difficult, dangerous bit.

There might be some interesting side effects from making simulation software, which is currently either an expensive niche or quirky university project (SPICE always has that feel).