This is very similar to what I wanted to make myself.
My inspiration came from my KSP campaign, where I built a huge station on Mun's orbit with a lander, a small orbital repair ship and a mobile science module. There were different missions to repair a rover on the surface or install a new part on an existing satellite. I used to plan my "expeditions", figuring out how much fuel i would need and what's the proper way to complete all goals. I sometimes had the same feeling in Death Stranding. It was such a blast.
So the idea was to create an immersive game about completing missions on some moon, while also troubleshooting various problems and system errors during the flight with a help of manual. Every ship's system and every control would have some logic, so the player could understand how the ship works and in what way it's different parts are interconnected.
The problem is in my case for a single player non-sandbox game driven by some "narratve" flying as IVA and walking around as EVA would feel like 2 different games. I can see now that's not a case for yours sandbox project. Upgrading your ground base while completing different tasks, building orbital space stations and satellites, travelling to other planets - everything seems like a promising sandbox game.
Added the game to wishlist. Hope to play it someday!