The Hyperdrive is one of the three typical methods of travelling faster than light in science fiction; the other two being jump drive and warp drive. While the theories behind hyperdrive and its required other dimension of "hyperspace" are based on ideas forwarded by Albert Einstein, among others, it is currently considered scientifically impossible. While jump drives move a starship instantaneously, and warp drives move a ship through real space, hyperdrives operate differently.

The idea of hyperdrive relies on the existence of a separate, adjacent and contiguous dimension most commonally called "hyperspace," though "otherspace," "n-space" and "subspace" have also been used. When activated, the hyperdrive shunts the starship into this other dimension, where it can cover vast distances in an amount of time greatly reduced from the time it would take in "real" space. Once it reaches the point in hyperspace that corresponds to its destination in real space, it re-emerges.

Explanations of why ships can travel faster than light in hyperspace vary; hyperspace may be smaller than real space and therefore a starship's propulsion seems to be greatly multiplied, or else the speed of light in hyperspace is not a barrier as it is in real space. Whatever the reasoning, the general effect is that ships travelling in hyperspace seem to have broken the speed of light, appearing at their destinations much quicker and without the shift in time that the Theory of Relativity would suggest.

While in hyperspace, starships are typically isolated from each other and the normal universe; they cannot communicate with nor perceive things in real space until they emerge. To people travelling in hyperspace, time typically moves at its normal pace; 24 hours in hyperspace equates to 24 hours in real space. Hyperspace itself may appear as a pink swirl, total blackness, or as something that would drive a human mind insane should it be viewed.

In much science fiction, hyper-jumps require a considerable amount of planning and offer a margin of error of some significance. Therefore, jumps cover a much shorter distance than would actually be possible so that the navigator can stop to "look around" -- take his bearings, plot his position, and plan the next jump. The time it takes to travel in hyperspace also varies. Travel times may be in hours, days, weeks or more.

Hyperdrives allow for much drama in science fiction. While starships using warp drive can race from star system to star system, fighting each other the entire way in between, ships with hyperdrive cannot. The chance of two ships appearing in deep space to take a navigation bearing at the same time is infinitesimal. Therefore, hyperdrive ships will encounter each other most often around contested planets or space stations. Hyperdrive also allows for dramatic escapes as the pilot "jumps" to hyperspace in the midst of battle to avoid destruction.

It should be noted that the warp drive used in the Star Trek universe relies on a bubble of "subspace" being wrapped around the starship, thereby enabling it to travel faster than light in real space.

Hyperdrives are the main FTL technology in many science fiction universes. Examples are:

• The Star Wars film series (created by George Lucas) which premiered on May 5, 1977.
• Starship Troopers by Robert Heinlein.
• Midshipman's Hope and subsequent novels by David Feintuch .