Star systems have list of properties of about planets in the system in table format. Typically the planet's the planet's name; type, semi-Major axis (orbital radius); orbital period, and rotation (length of the day) are considered mandatory information. Including the planet's mass, radius, circumference, gravitational acceleration, temperature, and escape velocity is consider optional information. For each planet one should also list any major cities, orbiting stations, or nearby orbiting fleets found on the planet.