Also, for a basic understanding of the physics at work, he could also try Kerbal Space Program. Its been one of the best tools to teach me of escape velocities,

Also, for a basic understanding of the physics at work, he could also try Kerbal Space Program. Its been one of the best tools to teach me of escape velocities, suborbit vs orbit, etc. Its not exact but very good at explaining the principal behind all the rules of physics.