It was an adaption of warp drive capable of propelling a vessel close to 2,200 times light speed, which in the 23rd century equated to warp factor 13. Unfortunately, when a vessel approached that speed, it departed subspace and transited into another universe, killing its crew.
Sometime between May and November 2267, experiments commenced in the Gamma Canaris region. During their approach to warp 13, the five vessels disappeared. The USS Enterprise was dispatched to investigate. Captain James T. Kirk was aware that the inventor of warp drive, Zephram Cochrane, and The Companion lived on nearby Gamma Canaris N, so he asked Cochrane for help. The warp expert devised engine modifications that would allow the Enterprise to reach hyperwarp speeds. Before they could be implemented, however, The Companion herself accelerated the starship, protecting it and its crew as they emerged into a starless universe. The missing ships were located, but their personnel had all died during the transition. (TOS comic: "A Warp in Space")
- These events took place between May and November 2267 according to dates cited in ST novel: Federation.
In 2311, hyperwarp was considered a fictional technology based on transwarp. It was used to confuse the Federation's enemies in 2311. The USS Universe was used as a test bed for this 'technology'. (TLE novel: Serpents Among the Ruins)