The warp 2 barrier was a warp barrier.

Warp factor 2 was the theoretical maximum warp speed in the early stages of Vulcan and Earth warp technologies. After the invention of warp drive by the Vulcans, it took them a hundred years to design an engine capable of breaking the warp 2 barrier. (ENT: "First Flight")

In the 22nd century, such Earth ships as the ECS Horizon, an Earth Cargo Authority operated J-class freighter commissioned in 2102, and the Starfleet operated Neptune-class survey ships were among the early ship classes with warp capability limited in technology by this barrier. (ENT: "Horizon", "Singularity")

It was not until the 2140s that the warp five engine conceived at the Warp Five Complex by Henry Archer broke the warp 2 barrier. In 2143,Commanders A.G. Robinson and Jonathan Archer demonstrated this advanced warp engine in the second NX-class prototype, the NX-Beta, by holding the ship steady at warp 2.5. (ENT: "First Flight")

After the warp 2 barrier was broken, it became possible to upgrade older starships, such as the Y-class freighters, with a warp three engine. (ENT: "Fortunate Son") Freighters used by the Federation still remained limited to the speed of warp 2, even as late as the 2260s. (TOS: "Friday's Child") In the 2360s, subspace resonators used by Starfleet could be modified to function as warp cores, though ships using them were limited to warp 2. (TNG: "The Next Phase")

See alsoEdit

• Flux paradox
• Time barrier
• Transwarp threshold