Kerbal Space Program is indie space game (can be found from steam). Its NASA simulator. You basically play as NASA, build your rockets, do various space missions and travel to other planets and collect research data to unlock new tech. You need to plan everything carefully as you have to use realistic orbital mechanics and physics and if you fail to get back to home you lose everything you took with you. Jebediah Kerman is starter astronaut in KSP.
You can find a lot of videos about Kerbal Space Program in youtube.