Structural Integrity Fields
The structural integrity system reinforces the structure of a starship to prevent it from literally flying apart at high speeds.

Operating at warp and impulse speeds places the structure of a starship under enormous strain. Although the ship's spaceframe is built to the highest standards, this in itself is not sufficient to resist the stresses generated by the propulsion systems, so the structure of the ship is reinforced by a network of forcefields known as the the structural integrity fields (SIF). The forcefields are distributed around the hull by a network of molybdenum-jacketed triphase waveguides. Conductive elements are built into all the major structural elements of the ship, and when the field is active it can increase their loadbearing capacity by as much as 125,000 percent. Other feeds increase the structural integrity of the hull.

On a Galaxy-class starship the structural integrity field is produced by five generators. Two of these are located on deck 32 in the engineering hull; the remaining three are on deck 11 in the saucer section. There are also two backup generators, one in each hull, which can provide 55 percent of the maximum rated power for as long as 12 hours. Each of the generators is made up of twenty 12 megawatt graviton polarity generators which feed two 250 millicochrane subspace field-distortion amplifiers. The generators produce an enormous amount of heat, but this is dissipated by a pair of continous-duty liquid helium loops, which can disperse 300,000 megajoules per hour. The generators are designed to go 1,500 hours between routine services. They normally operate on a cycle of 36 hours on an 24 hours off. When the generators are down they are degaussed and undergo routine maintenance. At least one generator in each hull is active at all times. If the ship is required to perform unusually stressful activities, more generators can be brought online.

During Red and Yellow Alerts, all the generators are on standby, ready for immediate activation. This is important because the SIF is an essential part of the ship's defenses and can compensate for most hull breaches. The damaged area is instantly sealed with a forcefield, equalizing the pressure of the entire vessel. In emergencies, additional power can be diverted to the SIF from other sources, such as the warp engines. If necessary, other systems can draw on the power of the SIF generators, but this is rarely done, because if the SIF fails it almost invariably leads to the disintegration of the ship.