Missions are usually collections of Ships (tracks) like an album, an EP, or a single. Explorers may join a Mission by following, commenting, or investing their Creative Energy units. The more Explorers that join a Mission, the sooner it will launch.
Missions are found in the Mission Control node when they are in pre-production or production phases. They are moved to the Launch Pad when all of the Ships are fully built and ready to launch.