Quantum slipstream technology is one of the most advanced propulsion systems ever encountered by Starfleet and is still very much in the experimental stage.

The quantum slipstream is an extremely powerful means of propulsion that can transport a vessel at speeds in the upper warp 9.9 range. The velocities involved are so great that, in theory, the slipstream could carry a ship across the galaxy in a single day.

The quantum slipstream is actually a narrowly focused, directed warp field that is initiated by manipulating the fabric of the space-time continuum at the quantum level. It works by focusing a quantum field through a deflector dish to generate massive changed in local space curvature; this creates a subspace tunnel, which is projected in front of the vessel. Once a ship has entered this tunnel, the forces inside propel it at incredible speed.

The slipstream is large enough to accommodate more than one vessel, so another vessel can enter the slipstream and accompany the vehicle this is generating it. In order to initiate a controlled shutdown of the quantum drive, the field strength has to be reduced by 50 percent. This can be done by reversing the drive's polarity.

The only fully functioning slipstream drive was encountered by the crew of the USS Voyager NCC-74656 in 2374. It was under the control of an alien called Arturis who belonged to an advanced race that had been assimilated by the Borg. The crew of Voyager managed to modify their vessel and had some success in creating a quantum slipstream, but analysis showed that these modifications cause too much damage and any further use would result in the total destruction of the vessel.

Sometime later, the crew of Voyager were successful in creating an alternative method of creating a quantum slipstream, but again this drive proved unreliable. The main problem with this system was the instability of the quantum slipstream. In order to maintain the slipstream a ship has to constantly modify the quantum field with its deflector dish. However, the calculations proved to be too complex for the crew of Voyager to resolve.

When Voyager returned to Earth, all the available data was transferred to Starfleet R & D and in 2382 the USS Leviathan was retrofitted with a quantum slipstream drive (QSD). The Leviathan was replaced in late 2383 by the USS Leviathan, which was fitted with a new QSD which had been developed using information provided by the Catatonians, who had been using quantum slipstream technology for centuries.

Although quantum slipstream propulsion is still very much experimental, with the advances in trans-warp drive technologies, it is no longer being actively developed.