As I write this, my fictitious deltawing spacecraft has just rounded apogee in Earth orbit, at which point I turned on my thrusters to even out the perigee a bit. All this with realistic graphics and displays, and simulated behavior that follows the laws of physics in real time.
The simulator also provides real-world spacecraft like the shuttle Atlantis, ISS, Mir, and so on. Interplanetary travel is supported, but I’m a long way from mastering that yet. Right now I’m pleased merely to have achieved a stable orbit.
If I’m lucky, I might actually learn how to land so I can end this journey without crashing.