The heart of the game is the space missions, which come down to dice rolls. At each step of a mission, the safety factor of the relevant component is checked against a random number, adjusted by relevant astronaut skill bonuses (if the mission is manned), safety penalties and other factors. If the check fails, an error occurs. Such an error may range from catastrophic mission failure down to no effect (e.g. "The first imprint in the lunar surface is in fact made by a helmet visor. Crewman okay."). Placing a satellite in orbit has three steps, while a Moon landing can have well over twenty. Missions are generally non-interactive; occasionally during an incident, the player may be given the option of aborting or proceeding.