Spaceports were the centers for extraterrestrial travel. In their prime, they sent up whole colonists into space, and managed the transportation of ships, people, supplies and materials between the Earth's surrfice and outer space colonies.
Unfortunately, they were the primary targets of The Apocalypse during the Shadow Years and are usually found in the center of an extremely devastated area, saturated with hard radiation. The construction and shielding of the spaceports was such that many survived, relatively unaffected by the holocaust. If one is lucky, that one could find spaceports filled with highly complex equipment, unusual cargo, a wide range of robots, aircraft, space-shuttles, and possibly a starship capable of faster-than-light travel. Given the purpose of a spacepart, to say "the sky's the limit" to what one might find is a gross understatement.