Haha, a little weird, but that's actually what I had in mind. Of course, a mod with actual human proportions would be preferable (although I'm sure, not very feasible). Orbiter has been my go-to spacesim on and off since 2001. There is even a new Orbiter version in the works that will bring 3D terrain and better texture resolution. Thing is, KSP has kind of spoiled me. Like you say, Orbiter has UMMU, but Orbiter is fundamentally not well designed for EVA's, or base building for that matter. Plus, I've rather come to enjoy actually building my own rockets, rather than depending solely on cool, yet unrealistically whimsical spaceships (IE: DeltaGlider). Plus, KSP has things like object collision, or (often through the use of mods) "universal effects" across all vehicles. As opposed to Orbiter, where one ship supports EVA's, while another may not... or one ship may have reentry damage effects, while another doesn't, etc. It often becomes a pain when planning missions using multiple incompatible crafts. Most importantly, I love that KSP is a persistent system. Unfortunately, KSP with real-sized planets and real solar system is kind of unwieldy. I've yet to run it successfully on my high-end laptop without a significant hit on performance. But I may look into it some more later.