Martin Schweiger's Orbiter Space Flight Simulator
"Go Play In Space" (Second Edition) by Bruce Irving.
Fun with Martin Schweiger's Orbiter Space Flight Simulator. This Introductory Tutorial manual is a colorful picture book about humans going to Mars, how they might realistically go about this, and where this might lead in the future.
Download Go Play in space here
Downloads - Go Play In Space v2 by Bruce Irving