While the ultimate goal of the game is to conduct a successful manned Moon landing, it is necessary to complete several milestone achievements to ensure success. Historical milestones in the game range from launching a satellite, like Sputnik 1, to conducting a lunar orbital mission, like Apollo 8. Skipping a milestone results in a safety penalty to any mission depending on it. For example, skipping a manned lunar orbital mission would cause a safety penalty to all mission steps during a Moon landing mission.