"Slipstream" is a science fiction term for a fictional method of faster-than-light space travel, similar to hyperspace travel, warp drive, or "transfer points" from David Brin's Uplift series.
Quantum slipstream was a starship drive used in two episodes of the science fiction television series Star Trek: Voyager. It first appeared in the season 4 finale, "Hope and Fear". Similar to the Borg transwarp conduits, the slipstream is a narrowly focused, directed field that is initiated by manipulating the fabric of the space-time continuum at the quantum level using the starship's navigational deflector array. It works by focusing a quantum field through a deflector dish to generate massive changes in local space curvature. This creates a subspace tunnel, which is projected ahead of the vessel. Once a ship has entered this tunnel, the forces inside propel it at incredible speed. To maintain the slipstream, a ship has to constantly modify the quantum field with its deflector dish; however, the calculations involved are too complicated, and the time available too short for 24th-century Starfleet computer technology. When this technology was discovered by the crew of the lost and stranded USS Voyager, it was hoped this could be used to allow the starship to travel at even greater speeds: the first test of this drive allowed the ship to travel 300 light years in minutes.