Impulse Drive

The impulse drive is a subluminal propulsion manifold present on effectively all Starfleet vessels. Other species have developed similar subluminal propulsion technologies, although not identical.

The official designation for an impulse engine is an "specific impulse accelerated ion propulsion manifold", although the component is colloquially referred to as an impulse drive/engine.

Function
Impulse engines serve as the primary method of subluminal propulsion among Starfleet and other human-manufactured vessels.

Design
Impulse engines are typically placed on the trailing edge of a starship's saucer hull (or corresponding component). There are almost always two or more engines present. If one fails, the other(s) take(s) over.

An impulse engine usually takes the form of a cluster of ion acceleration tubes (called "channels"). The shape of the cluster is irrelevant.

Impulse engines operate via accelerated ion propulsion. Ion propulsion was developed during the late 20th and early 21st centuries as an electric (non-chemical) replacement for RCS thrusters, with potential applications in deep space transportation. Impulse engines improve upon the original manifold via the addition of electromagnetic acceleration fields.

Most impulse engines are driven by impulse reactors, which generate the ions used in the channels. The energy emitted by the reaction is then used to power the main thruster manifold and the electromagnetic acceleration fields.

Most impulse reactors are fueled by diatomic gases (usually hydrogen).

Hyperion Impulse Drive
Main Article: Hyperion Impulse Drive

The Hyperion impulse drive was developed by Frontier Aerospace as an improved method of subluminal propulsion for their Revolution-class, Sentry-class, and Phoenix-class starships. The primary difference between a typical Starfleet impulse engine and a Hyperion impulse engine is the addition of secondary and tertiary electromagnetic accelerant fields.