Saucer separation
Saucer separation is an emergency manuever performed on some Federation starships. It involves the complete disconnection of the primary hull and the secondary hull. Prior to the 24th century, separation was used as a means of abandoning either hull in the event of a catastrophic emergency. It was a one-time only event, and the hulls could not be reconnected without external support. By the 24th century, separations were designed to be more routine with some classes being designed with reconnection abilities. Both components contain essential systems, allowing each to be independently operable for extended periods.
Classes capable of separation
In the 23rd century, most classes with the saucer/engineering hull layout were capable of separation, including the Constitution class. Separations were only for emergency purposes; the two sections could not reconnect easily following a separation.
By the 24th century, starship classes were designed to routinely separate into one or more components. The Galaxy class is one such example, as is the Prometheus class.
Separation sequence
On the Galaxy class, saucer separation was primarily designed as a way for the civilian and nonessential crew complement to escape in the saucer section, while the senior staff and essential personnel engage a threat or enter a potentially dangerous situation in the stardrive section.
In a starship separating due to these circumstances, the separation command is issued by the commanding officer from the main bridge. The CO, along with most of the senior staff, transfers to the battle bridge on the stardrive section via a dedicated emergency turbolift, while a junior officer is typically left in command of the saucer module. The saucer is almost always given the directive to seek safety by retreating to a starbase or other allied territory.
Evacuation of nonessential personnel from the stardrive section is conducted by security staff. Audio warnings are given to the crew to alert them of the pending event and how much time is remaining to vehicle separation.
During the actual separation event, the docking latches, on the stardrive side of the ship, collapse and retract into the hull of the stardrive section. An autoseparation is generally used to separate the two components of the ship although a manual option is also available. The separation is monitored from the main bridge and battle bridge by the conn officer and Operations manager. Staff in Main Engineering can also provide support during a separation.
The drive section, containing the ship's warp drive and the majority of weapons systems, is then free to confront danger without endangering the lives of nonessential crew.
Following the crisis, the two sections can rendezvous and rejoin. Connection is generally the reverse process of separation, again with automated and manual options.
Separation can also be performed at warp speeds, although it is much safer at lower warp velocities due to the fact that the saucer is not equipped with warp drive, only impulse engines. During a high warp separation, the stardrive section would need to slow down just long enough for the saucer, still riding the decaying warp energy, to clear. Otherwise, there would be risk of the stardrive section slamming into the rapidly slowing saucer. The procedure is extremely risky, and there is no margin for error. A high warp separation was never attempted prior to 2364.
Emergency landing of saucer section
The saucer sections of many starship classes are designed to make planetfall on a suitable planetary surface, preferably Class M. The saucer must be making a level approach and heading towards the ground at a shallow angle. The area chosen for landing must be smooth and relatively free of obstruction. The great structural stresses placed on the spaceframe of a landing saucer section would most likely prevent it from being returned to spaceflight.
Examples of separation
Tactical uses
The USS Enterprise-D used saucer separation as a way to confront the Q entity on its first mission in 2364. Captain Picard left Lieutenant Worf in charge of the saucer section. The separation was the first to be conducted at high warp.
During the reconnection of the ship, Picard ordered new first officer William Riker to conduct the docking manually. The bridge crew were somewhat apprehensive about the plan, but Riker performed well. He safely rejoined the two sections without any automated assistance, proving himself to Picard.
Commander Riker suggested a saucer separation shortly before the Enterprise was sent to investigate possible Romulan activity later that year, although Picard felt it was too early to justify such an action.
The Klingon criminals Korris and Konmel were fascinated by the stardrive section of the Enterprise and were excited at the prospect of hijacking it for their use in battle. They attempted to get Worf to assist them in accessing the battle bridge and separating the ship, but fortunately Worf was loyal to the Enterprise crew.
Also that year, acting captain Geordi La Forge separated the ship to return and fight the automated weapons drones on planet Minos. Chief Engineer Logan was ordered to take command of the saucer section and take it to Starbase 103.
In 2366, Commander Shelby suggested separating the ship and using the saucer to create a distraction for the Borg. Commander Riker rejected the idea, feeling the saucer's impulse engine power would be of use in the battle. Shelby briefed Picard on her plan despite Riker's objections. Later, Riker used Picard's knowledge of the plan to his advantage during a rescue attempt to retrieve Picard, assimilated as Locutus. Following the devastating Battle of Wolf 359, the Enterprise caught up to the Borg cube, then engaged the vessel and separated. As expected, the Borg focused their attack on the stardrive section, ignoring the saucer module. This allowed the saucer to launch a shuttlecraft, masked in an antimatter spread, to the cube. Commander Data and Lieutenant Worf successfully transported aboard the cube and abducted Locutus, which was a crucial event leading to the defeat of the Borg in orbit of Earth.
This use of saucer separation was perhaps inspiration for the multi-vector assault mode of the Prometheus class, launched in 2374.
Emergency uses
The only use for saucer separation in early starship classes was for emergency purposes related to crew survival. In 2267, Captain James T. Kirk ordered chief engineer Montgomery Scott to jettison the nacelles and escape in the saucer section when the original USS Enterprise was threatened by Vaal at Gamma Trianguli VI. Ultimately, the separation was never ordered.
Obviously, the Galaxy class could also use saucer separation as a way to ensure crew safety. In 2365, saucer separation was considered in order to quarantine the cargo bay of the Enterprise-D when it was feared that a plasma plague strain had escaped a containment facility.
When Ansata terrorists planted an implosion device on the warp core of the Enterprise-D during an attack in 2366, Captain Picard ordered a saucer separation. Fortunately, Commander La Forge was able to remove the device and beam it into space before it detonated.
In 2367, Dr. Noonien Soong used a signal to temporarily cause Data to use any means necessary in order to return to Soong's home planet. He caused an environmental system failure on the bridge, then locked himself on the bridge and severed all command functions. Data then plotted a course to Soong's planet at high warp. Picard and the senior staff, in Main Engineering, attempted to separate the saucer in order to restore computer control to the stardrive section. The plan was to then incapacitate the saucer with a tractor beam once the separation was complete. However, Data was able to discover the separation command and cancel it before it could be carried out.
The Enterprise struck a quantum filament in 2368, disabling most of the ship's systems and causing a gradual failure in antimatter containment. Ensign Ro Laren pushed for a saucer separation to protect survivors in the saucer section, but doing so would condemn those in the stardrive section to certain death when the core breached. Deanna Troi, the senior officer on the bridge at the time, decided to delay separation and use power from the bridge to activate crucial displays in Engineering. Commanders Riker and Data saw the displays right before the ship was to separate, averting the containment breach.
Unfortunately, the Enterprise-D was required to separate for the same reason three years later, in 2371. Serious damage was inflicted to the ship as a result of an ambush by the Duras sisters, and the warp containment system was critically damaged. The entire ship's complement was evacuated to the saucer and it reached safety just as the drive section exploded. The shockwave from the blast shoved the saucer section into the atmosphere of planet Veridian III, where the ship was forced to make a crash landing. There were light casualties, although the ship was deemed unsalvageable.