Orbiter is a free spaceflight simulator, it's got much more detail on the actual flying and vehicles than KSP, but lacks the building and real time rigid body physics that provide so much entertainment in KSP. But if you want to experience real spacecraft then it's probably a better choice Orbiter is developed by Martin Schweiger and can be downloaded for free from http://orbit.medphys.ucl.ac.uk/ The Vostok Plugin I use is by Igel it supports all of the Vostok missions - including the ones with animals as passengers. http://www.orbithangar.com/searchid.php?ID=6318 Videos featured in the credits: https://www.youtube.com/watch?v=6ogimwkItds https://www.youtube.com/watch?v=qrnp-y8mnFg