How long does it take to fly to Mars? It takes from 6-9 months to get from Earth to Mars using the least fuel possible. That's a long time, and what's worse the Earth-Mars launch window only occurs approximately every 2 years. This 2-year constraint is true for science research missions as well as for humans visiting the Red Planet. In this game, the orbits of Earth and Mars are animated, and the player launches a spacecraft at the right moment to intercept Mars (and then again to return to Earth). Since this is challenging, the game provides a Help function.