It's a quick path to having something to play with but I'd encourage folks specifically wanting to learn something new or create something for a portfolio to try to have it be more the other way around: write 90% by hand, implement the features yourself, and have AI help you with the research and debugging (but not try to automatically write the code to fix the bugs). AI is really great at all of the things listed, but I guarantee if you were in an interview and someone asked you about this project your responses about how and why everything works would be 2x-3x stronger.

If this was your 3rd time implementing an orbit simulator and you just wanted to get the bulk done quick so you could move on to work on new stuff then that's when having AI write the bulk & doing checking really works best as you're already an expert in what needs to be done rather than trying to learn about what needs to be done from someone/something else doing it for you.

I say this as an orbital dynamics simulator in C++ having been one of my first big projects I put in a portfolio myself :). And I also like to use AI often, I'm not an AI hater in general, just I like to use in certain specific ways sometimes.

Feedback on the UI side: It'd be cool if the stars used more random positions rather than sine/cosine looking patterns. There are lots of different approaches one could try (from simple random positions to very complex types of clustered randomness and brightness variation to realistic star maps). My suggestion would be to ask AI what types of approaches could be taken and try implementing whichever approach sounds the most fun!

This breaks my heart, software modeling orbital mechanics is something I do for fun from time to time.