Ether Drive

Note: This article discusses material that was once considered canon but whose canonicity is now questionable due to contradiction by newer sources.

An Ether Drive is a Tau spacecraft engine that allows for faster-than-light travel through the boundary between realspace and the Warp. Despite the Tau’s lack of psykers, and not being able to harness or grasp the full opportunities that the Warp presents, the Earth Caste have nevertheless developed an effective drive system that is sufficient to suit the needs of the Tau Empire.

History
On the innermost of T’au’s seven’s moons, a routine geological survey discovered the remains of an alien vessel. The significance of the find did not disrupt Tau society as much as might have been expected. Tau theorists had long reasoned that other life forms existed and the verification helped confirm the belief that there was a greater destiny awaiting them. No Tau commented on the sheer good fortune of finding the technology that they so desperately needed on their doorstep just when they needed it.

The Tau were able to duplicate the Warp Drive of the alien ship but the initial test flights were disastrous. Achieving transition to the Warp required more than technology, it required psychically attuned minds; and the Tau race boasted no psykers. Without them to guide the transition, no amount of power could breach the dimensional barriers. The best the Tau could do was make a partial transition, forcing themselves into the void that separated the Warp and real space before they were hurled out again like a ball held under water then released.

Data gathered at great cost during the test flights was studied closely. Water Caste scientists made the observation that the boundary between real space and Warp space was not a neat line. It was closer to being a turbulent ocean fomented by the tempestuous Warp tides below. By carefully angling their descent toward the Warp and extending the field generated by the gravitic drive into a wing, shaped to hold the vessel down a Tau vessel could extend the duration of the dive considerably. The speeds achieved in the ascent back to real space were staggering and this coupled with the effect of the Warp on time and space ensured that the real distance covered by the dive was immense. Early tests lost several Drone ships because they inadvertently passed far beyond the sensor range of their recovery vessels.

The details were soon resolved. There was still a major constraint, only the most powerful (and bulky) drives could sustain the gravitic wing throughout the dive and the power drain meant that considerable recharge time was needed between dives. Also by comparison to actually navigating the warp the pace was still very slow. Taking typical Imperial Warp speeds the Tau drive was slower by a factor of five. The speed was consistent though, and did not expose the Tau to the perils of the Warp; enabling the Tau to expand beyond their home star for the first time.