If you are one of the many thousands of people who ever dreamed of booking a holiday into Earth orbit, or dreamed of exploring the Moon, Mars and beyond, but, can't afford the price tag, here's the next best thing.

The Orbiter Spaceflight simulator by Dr. Martin Schweiger of UCL, it’s free, fantastic and downright addictive.

Orion Spaceship Orbiting Mars (Orbiter Simulation)

ORBITER is a free flight simulator that goes beyond the confines of Earth's atmosphere. Launch the Space Shuttle from Kennedy Space Center to deploy a satellite, rendezvous with the International Space Station or take the futuristic Delta-glider for a tour through the solar system - the choice is yours.

For an excellent introduction to Orbiter, read The Space Review article by Bruce Irving and Wikipedia's Orbiter page. Bruce Irving has also co-authored with Andy McSorley an outstanding first time users’ guide entitled 'Go Play in Space’ With this simulator you can fly practically every spacecraft real or imaginary ever conceived because of the various add-ons developed for it. My favourite is the one developed by Erik Anderson, Alain Hosking and Wolfgang Schwarz titled 'World of 2001: A Space Odyssey' which brings this science-fiction classic to life.

Since Orbiter is a space flight simulator, flying spacecraft is kind of the point. In making a universe full of flyable ships from 2001, we had to extrapolate a bit. Not only did we need to make an Orion III space plane, but also the booster stage, and the catapult to launch them both. And we needed the Orion II cargo spaceplane, to fly payloads into space. The Titov V spaceplane is mentioned in the novel; we wanted to be able to fly it too! Of course, all of these and more come with bases to fly to such as Clavius, Tycho, and Tchalinko on the moon, Port Lowell on Mars, and more.