For a game of this kind tripulated missions and science should be keys.

I think it would add quite a lot to the gameplay to make cockpit and habitable modules with interactive interiors, so you can move around, go to the pilot sit and have all the controls, screens with info... or go to a lab, go to a bed, pick objects and interact with them (use a microscope, a material analicer, move resources for ISS like storage...)

If you go crazy you could even add VR(?)