Preparing for phase drift...
—Unidentified Charon helmsman
Phase engine propulsion systems (also known as phase drives) were the typical starship component on Charon Dominion warships and vessels that enabled faster-than-light travel. Relatively new technology for their people, as the Charon and vassal species had considered the "secrets" of faster-than-light travel to be lost technology, phase engines differed greatly from hyperdrives, principally in the manner which the respective components projected matter faster than the speed of light. The technology of phase engines were originally concieved by the Kathol civilization, who utilized the technology to venture into Otherspace millions of years before the Great Collapse.
Whereas hyperdrives utilized tachyonic hypermatter to propel matter faster than light without damaging or altering its mass or energy by "pushing" through hyperspace "ripples", the phase engine "shifted" mass into an alternate dimension called "phase space" by opening a passageway between two points in spacetime, which was only possible through the utilization of protomatter. Unlike vessels in hyperspace, ships in phase space were still visible, albeit translucent and with a faint and luminous glow. To most, ships in phase space appeared to possess a blue aura, although ships with a destabilized phase engine or damaged components often had a red aura. This strongly suggests that phase engines utilized some degree of the electromagnetic spectrum, as higher frequencies and shorter wavelengths seem to suggest stable phase engines, while lower frequencies and longer wavelengths imply unstable phase engines. In common vernacular, engaging a phase engine is known as a "phase drift", much like the terminology of a "hyperspace jump".
The hyperdrive has several advantages over the phase engine, including faster transit and superior operational requirements. One of the most restrictive limitations of the phase engine is that it cannot be operated while the vessel it is installed in is in motion; a ship must be at a full stop in order for the phase engine to begin operation. In addition, the phase engine has a single standardized speed that is approximate to the Class 2 hyperdrive, a discovery made during the Extant War. The only believed advantage the phase engine has over the hyperdrive is that it produces no unstable radiation or reaction when damaged, aside from decreased performance, and is capable to traversing the Hellmouth.
Another particular benefit of the phase engine is the reduced restrictions on communications and sensor systems; ships traveling in phase space occupy "phase lanes", which are created at the moment a ship begins phase space transit. While in phase space, vessels are fully visible to one another in their lanes, communications are not hindered by phase space transit, and as shown by the several engagements shortly after the Extant War began, ships in phase space are capable of tracking ships in hyperspace though unknown means.