Links

Kerbal space program:

https://kerbalspaceprogram.com/en/

Take on mars Tutorials:

https://www.youtube.com/user/LearningByGaming

Universe sandbox 2 :

http://universesandbox.com/

Simple rockets:

http://jundroo.com/simplerockets-has-launched/

Kerbal space program tutorials/​Scott Manley:

https://www.youtube.com/user/szyzyg