Saucer separation

In the Star Trek fictional universe, saucer separation is the term used to describe when the saucer section on certain types of Starfleet starship disengages from the stardrive section. This was first employed on the show in Star Trek: The Next Generation ' s opening episode, "Encounter at Farpoint, Part I", and was subsequently employed in later episodes (such as Arsenal of Freedom and The Best of Both Worlds (TNG episode)) and movies.

Numerous Starfleet ship classes, such as the Constitution class and Galaxy class starships, consist of two sections: the stardrive section, also known as the battle section, engineering section, engineering module, or secondary hull, where the warp engines and Battle Bridge are located, and the saucer section, also known as the primary hull or command module. In times of battle, it was intended that the saucer section of the ship would separate from the stardrive section of the ship. Carrying all the non-essential personnel, this section could travel away from the battle, while the stardrive section could engage the enemy in battle. If the outcome was successful, the two sections could be rejoined.

In extreme emergencies, there is a protocol developed to allow the saucer to make a forced landing on a habitable planet, but the craft is not especially designed for this maneuver and is usually severely damaged and made a total loss upon completion. Until the crash of the Enterprise-D saucer, Starfleet engineers doubted that a Galaxy class saucer could survive a deorbit burn and crash landing on the surface of a planet.

While the Galaxy class was built with saucer separation in mind, the saucer section did not have warp drive, which made the saucer section vulnerable to enemy attack. About the only way to safely perform the separation was to withdraw to a safe haven, and separate the saucer away from the battle. The stardrive section could then return to the battle. However, most situations developed so quickly that there was no time to separate at a safe distance, nor was there usually time during battle to withdraw to separate the saucer.

Normally, the separation needs to take place an impulse speeds. While the crew of the Galaxy class Enterprise proved that separation at warp was possible, to do so is very dangerous. Separation at warp has absolutely no margin for error. Such dangers included collision between the two sections, as well as problems with the warp field. If the geometery of the warp field was not optimal, the field could rupture upon separation. In situations where a saucer successfully detached at warp speeds, the saucer module would usually drop out of warp within two minutes.

By 2366, the maneuver was already quite rare during battle. Most times saucer separation would take place during maintenance layovers at starbases. As mentioned, the separation of the Galaxy class Enterprise was only seen four times during the lifetime of the vessel. However, the maneuver was also performed in the course of at least two novels, that being Foreign Foes and Rogue Saucer.

Most times separation of the saucer and stardrive sections took place in spacedock in order to perform maintenance. One such example of this was when the Battle Bridge module of the Enterprise-D was replaced after the first season of The Next Generation.

Nearly every starship design that follows the saucer/secondary hull pattern has had some ability to separate the saucer from the stardrive section during extreme emergencies. This would be in the event of both a warp core breach and the failure of the ejection systems. But even if the two sections could later be reconnected, it was only possible at drydock facilities. The idea of separating and reconnecting the two starship sections on the fly was only a recent innovation in starship design.

Starfleet did not entirely abandon the concept of separable starships: an experimental warship, the USS Prometheus, included "multivector attack mode," in which the ship separated into three parts which could attack a threat independently. ("Message in a Bottle", Star Trek: Voyager) In the Prometheus class design, each of the sections had their own warp engines, which enabled the various parts of the ship to engage enemies at warp speeds.