The Quantum Slipstream Drive is an advanced form of interstellar propulsion. It is similar to the Borg transwarp drive. The drive allows for speeds far exceeding those which conventional warp drive can achieve, but the technology is extremely hazardous to use.
It was the main form of propulsion on ship belonging to Species 116, posing as a Starfleet vessel called the U.S.S. Dauntless. This vessel was ultimately lost to the Borg when the plan of the ships owner Arturis to have the Voyager crew assimilated failed.
However the Voyager crew had gained an insight into the ships technology and they themselves attempted to adapt the drive onto their ship. They faced many problems in their attempt, mostly stemming from the fact that the hull of a standard Starfleet vessel is not designed to withstand the enormous forces that occur when entering the Slipstream corridor.
USS Voyager Edit
After her second assimilation Seven had retained the knowledge of Species 116 and believed she could adapt the drive to work with Voyagers systems. She estimated the development time to be 1 to 3 years. (JB: "Just Between a Rock & a Hard Place")
The Voyager crew attempted to overcome the hull integrity problem by bolstering the ships integrity field to counter the velocity of the ship. They implemented this technique in secret on the Edison, a shuttlecraft, but the maiden test flight ended in disaster.
The Edison came close to a spatial anomaly which emitted an unknown type of radiation. It disrupted the slipstream corridor and caused the shuttle to exit into normal space at high velocity. To avoid destruction the shuttles computer ejected the warp core but the resulting feedback completely destroyed the deflector grid. This feedback resulted in the drive fusing itself into an unworkable lump of metal with the deflector array. If the core had not been ejected when this happened the shuttle would have most likely been destroyed.
The problem was caused by the fact that the shuttle was traveling so fast that by the time their, in comparison with the drive, outdated and slow sensors detected the anomaly it was far too late to avoid damage.
The shuttle did manage to travel 197.19 lightyears in a matter of minutes. In that respect the test flight had succeeded. The shuttle was however destroyed soon after due to the loss of the main deflector. It was unable to maintain hull integrity without the deflector as captain Janeway and Seven attempted to make an emergency landing on a uninhabited M-class planet in a G-type star system. It exploded in the upper atmosphere. (JB: "Just Between Stars")
USS Millennium Edit
The Borg Edit
When Seven of Nine had been re-assimilated and had been transformed into One of Many she stated that it had been this piece of technology that had allowed species 116 to avoid assimilation for as long as they had. The collective was also considering attempting to combine Borg transwarp drive with slipstream technology. One of Many considered the slipstream technology more elegant in use. (JB: "Just Between a Rock & a Hard Place")
As of 2379 the Collective had not implemented this idea. This was made apparent when the Starfleet vessel USS Millennium encountered a Borg Sphere, no mention was made of any apparent changes to their transwarp drive by the crew of the ship. (MLN: "Collective Comprehension")