 Each base is surrounded by five numbered intersections, representing the number of freight rings a player requires in order for one of their trade ships to land at the intersection so that a trading post can be established.Trading posts must be built in numerical order, and when a trading post is established, they are entitled to a Friendship Card from the aliens, which may grant the player special abilities.The trading outpost and Friendship Card are not subsequently lost if the player subsequently loses freight rings - the numbered intersections only serve to determine the order in which trading posts must be established, and the requirements for establishing one therein.