A ship has interchangeable mission modules. For example, a ship has a frame with a mission-module bay disposed therein. The bay is operable to receive a mission module having a mission-module system and an interface that facilitates the coupling between the mission-module system and the ship. As such, a plurality of different types of mission modules can be interchanged quickly and easily to provide the ship with different mission capabilities. Each mission-module is generally self-contained such that all the equipment necessary to perform the specific mission is contained within the single mission-module. Each mission-module is either a single unit or multiple units combined together to form an integrated unit. Thus, the ship is capable of transitioning from one mission to another simply by ejecting one mission module and replacing with another mission module.