Starships sometimes have to manipulate large objects (such as other ships or asteroids) at a distance from the ship. Examples include, towing a derelict or damaged vessel, stopping an enemy ship from fleeing, and clearing a path through an asteroid field or belt. To do this, they use tractor beams.
Tractor beams use emitters to project super-imposed subspace/graviton force beams onto a target object. This places spatial stress on the target, and manipulation of these stress patterns allows the ship to push the target away, pull it closer, or hold it in place. Main tractor emitters must be mounted directly to a ship’s primary structural framework to resist the stress and inertial potential imbalance created by tractor beam use.
The larger tractor beams on a ship are referred to as its main tractor beams. These usually include one aft ventral (for towing ships and so forth) and at least one forward for moving objects in front of the ship. In addition, ships have secondary tractor beams in its shuttlebays to help maneuver incoming craft. Typically, secondary tractors are usually at best class Alpha and Beta; main tractors are usually Gamma or Delta-class, but this depends on the size of the ship. Many ships have class Alpha tractors in their shuttlebays to help make smooth landings.
Multiphase Tractor Beams
Multiphase tractor beams allow warp engine power to be channeled to the tractor beam more effectively by using high-intensity overlapped meta-phasic subspace fields to break through interference that would normally nullify a tractor beam. This provides a greater range of uses for the tractor emitters, including embedded annular confinement beams (ACB) to the tractor beam itself, along the lines of Borg technology, to allow instant transport of emergency or boarding party personnel to beam aboard the ship targeted.