Saucer section

In the fictional Star Trek universe, many Starfleet ships are designed with two main sections: The "primary hull", or the saucer section, provides crew quarters and living facilities, science and mission facilities, weapons arrays, impulse engines, and command facilities such as the main bridge. The "engineering hull", also called the "stardrive section", or the "battle section", holds all warp drive-related components, as well as the main deflector (shield) array, stronger weapons, fuel and miscellaneous storage, and other systems.

Some Starfleet vessels had the capability to separate the two sections, whether as a disaster recovery tactic, or to bring only mission-critical functions into a dangerous situation.