Hyperdrive

"Okay, so at its base level, a hyperdrive allows you to travel great distances by entering and exiting subspace."

- Rodney McKay

Hyperdrives are devices which allow ships to break the light-speed barrier, enabling interstellar and in some cases intergalactic travel. They function by taking the vessel into hyperspace, where normal physical laws that would prevent faster-than-light travel do not apply.

Overview
A hyperdrive allows a vessel to open a subspace window and move into hyperspace. In this manner, a ship can cross vast distances without experiencing relativity. Hyperdrives vary in their effectiveness from race to race, with some being much faster than others; most hyperdrives are designed to travel within a single galaxy, while more advanced models can travel between galaxies in the same amount of time.

The effectiveness of a hyperdrive depends on two factors: design and power input. Given enough power, a hyperdrive can be made to go far faster than it would normally be capable, such as in the case of the Zero Point Module-powered Odyssey, which can reach speeds more than four times faster than its sister ships. The design of a hyperdrive is what allows it to make use of the power it's given effectively. The Odyssey, even with a ZPM, cannot match the speed of a fully-powered Atlantis' Stardrive (three ZPMs), which can cross the same distance as Odyssey in a fraction of the time. However, a fully-powered Stardrive is very rare; the Ancients have ascended or died, and the only other race shown to have the ability to produce Stardrives&mdash;the Pegasus Replicators (the Asurans)&mdash;have been destroyed.

Ancient
The Ancients were the first race known to develop hyperdrive technology, being able to make intergalactic trips millions of years before human life was ever seeded in the Milky Way and Pegasus galaxies, and possessed two types of hyperdrives. Their intergalactic hyperdrives were capable of making trips between galaxies, but they appear to have been confined to City-ships and their exodus ship. Even without a Zero Point Module, these hyperdrive can cross the massive void between galaxies in the amount of time it would take most hyperdrives to travel moderate interstellar distances; with a full complement of ZPMs, a City-ship is capable of traveling several million light years in only a few hours (many times faster than even the most advanced Asgard hyperdrive, though requiring and using up considerably more power by comparison).

All other Ancient ships encountered by the Tau'ri appear to be equipped with a much less powerful interstellar variant. These hyperdrives traversed subspace at a much slower pace than their intergalactic cousins, but were still far superior to every other hyperdrive except those of the Asgard and Ori. The Aurora-class boasted hyperdrives that could be modified to make an intergalactic trip if necessary, though they were usually ill-equipped to make such a journey and it is unknown how fast they would be (but likely far slower than an Asgard or Ori ship). It is likewise unknown if the rest of the Ancient fleet could be modified this way, but it seems probable.

Some success has been had with installing an interstellar hyperdrive on Puddle Jumpers, even though their range is small when compared to vessels equipped with even Goa'uld hyperdrives (albeit much faster) and their effectiveness is limited; using a hyperdrive drains the Jumper's internal battery after one jump unless another power source is interfaced.

Some early Ancient ships use an FTL drive instead of a hyperdrive. This type of engine is capable of intergalactic travel, but its speed relative to intergalactic hyperdrives is unknown. It is still faster than the interstellar hyperdrives of the Wraith and Goa'uld.

Asgard
Asgard hyperdrives are among the fastest hyperdrives ever created, being able to traverse the distance between close galaxies within hours. If equipped with an Ancient power source, Asgard hyperdrives are capable of traveling between Earth and Pegasus in four days, seen only to be exceeded in speed by a fully-powered City-ship; and even without a ZPM they are second only to the most powerful of Ancient drives. It is unknown how fast an Asgard ship can travel when using its own power generators, but it is likely to be slower than when using a ZPM. While in hyperspace, the weapons systems and defensive shields of a vessel using an Asgard hyperdrive are offline, due to the fact that the full power of the generators is required. As a result, a ship using an Asgard hyperdrive can be destroyed if a nearby vessel in hyperspace self-destructs; however, this occurrence is highly unlikely, as few races would be able to keep pace with them. Asgard ships have the ability to tow other vessels in their hyperspace field, but this causes the total travel time of the journey to be lengthened exponentially. The Asgard later granted the Tau'ri their hyperdrive technology, in thanks for their contributions in the battle against the Replicators.

Goa'uld
The hyperdrives on a standard Ha'tak are capable of reaching speeds of up to 32,000 times the speed of light, but due to the far-flung nature of the Goa'uld Empire a Goa'uld homeworld had to be within less than a years reach of a planet designated for conquest.

When Anubis upgraded the Ha'taks of his fleet, the ships became faster in an unknown degree. Many of these ships have since been absorbed by the Lucian Alliance.

Ori


Ori hyperdrives&mdash;having been designed with ascended knowledge&mdash;are capable of making intergalactic journeys if necessary and are so fast that they have proven capable of nearly keeping pace with the Asgard hyperdrive of the newly upgraded and Zero Point Module-powered Odyssey. Despite their incredible speed, the distance between the Ori home galaxy and the Milky Way was so great that a Supergate was required for the Ori crusaders to reach the Milky Way in a period of time acceptable to the Ori.

Tau'ri
The Tau'ri initially used Naquadria to power their first viable hyperdrive in the form of a buffered reactor core. Unfortunately, the Naquadria proved to be too unstable for Earth's level of technology, and the reactor required controlled amounts of energy to prevent an overload, which seriously limited the effectiveness of the hyperdrive. Earth later managed to acquire the hyperdrive of an Al'kesh from Ba'al, which was incorporated. This greatly increased the hyperdrive's effectiveness, but vessels were still forced to make short stops to prevent an overload.

The Asgard later granted the Tau'ri their hyperdrive technology in thanks for their assistance in battling the Replicators, which allowed Tau'ri vessels to make intergalactic trips without respite due to their vastly superior nature. (It is estimated that the Prometheus' Asgard hyperdrive is capable of speeds around 803.52 trillion miles per hour, or about 136 light-years per hour, or about a kilo-parsec per day.)

However, due to power requirements, a trip between the Milky Way and Pegasus galaxies took up to three weeks (which is still far beyond what every other encountered space-faring race is capable of, apart from the Ancients, Asgard and Ori). If a Zero Point Module happens to be powering the vessel during its journey between the Milky Way and Pegasus galaxies the trip can be shortened to a mere four days.

Earth is still continuing its own research into hyperdrive technology, and is currently developing a new generation of hyperdrives for its fleet.

Traveler
The Travelers have installed hyperdrives on their generational ships; however, they are&mdash;as Dr. Radek Zelenka described&mdash;somewhat crude. They are composed of mismatched components that seem to require continuous maintenance since&mdash;despite their relatively advanced technological state&mdash;most Traveler technology is old and likely out-dated. Despite this, they are relatively fast, able to keep up with the rest of the combined Wraith and Tau'ri fleet before the Battle of Asuras and able to beat the Daedalus (although not by much), which had a head start, to M6H-987 even after the Daedalus was partially disabled by Ronon Dex.

Vanir
The Vanir originally possessed the intergalactic hyperdrives that their Ida galaxy counterparts are famous for, however they were destroyed 10,000 years ago by the Wraith after the majority of Ancients departed for Earth. Due to lack of resources, they are unable to replace them, so they must rely on mere interstellar variants. Vanir hyperdrives are the first witnessed to accurately and safely open a hyperspace window in-atmosphere at their destination. It is unknown exactly how fast they are, though they are likely comparable to the unmodified hyperdrives of Ancient Aurora-class vessels.

Wraith
Wraith hyperdrives are believed to have been stolen from the Ancients, as Ancient hyperdrives are known to be compatible with those of the Wraith. Wraith hyperdrives are not as effective as that of other known races, since it takes them several weeks to cross distances in even a small galaxy like the Pegasus galaxy. Also, due to the organic nature of Wraith vessels, they must routinely exit hyperspace to prevent a build-up of radiation damage acquired via hyperspace travel, which severely limits their effectiveness. The Lantean scientist Janus developed a weapon called the Attero device, which was capable of destroying Wraith ships upon entering hyperspace. The device emitted a specific frequency that created turbulence in the layer of subspace utilized by Wraith hyperdrives, ripping their ships apart when they entered a hyperspace window. When being powered by a Zero Point Module, Wraith hyperdrives can travel fast enough to cross galactic distances in a much shorter time than normal.

Nakai
The Nakai use intergalactic hyperdrive in their motherships. The Nakai hyperdrive technology&mdash;when compared to other hyperspace capable races&mdash;appears to be extremely different, terms of a visual and sound effect it produces while entering/exiting hyperspace. The time it takes also seems slower, as a Nakai managed to send a signal and it took three weeks for two motherships to arrive at the location between galaxies.