In Mission Space players compete to be the first to get over 25 points by completing missions. Missions are either swinging around the Moon, orbiting the Moon, or landing on the Moon; the more difficult a mission is the more points are scored for successfully completing it. Points are also awarded for having fuel remaining and for rescuing players who run out of fuel.
The game is played by randomizing a mechanical "computer" and proceeding through a series of checkpoints - players landing on the Moon go through all checkpoints (there are 21) and players doing simpler missions skip some of them. At each checkpoint players simultaneously choose lettered navigational points and then the computer dial is turned to show the correct answer. Players who choose the correct answer skip one (in some cases two) checkpoints, while other players have to spend fuel to get to the correct location.
At certain checkpoints players consult a probability table to see how likely it is they can complete their missions given their remaining fuel. At these times they can choose to downgrade their missions.