Earth's first starship class capable of warp five, which carried humanity's first deep space explorers in the 2150s.
The NX-class was the first Earth starship design able to reach warp five, built around the engine developed at Starfleet's Warp Five Complex. Its compact saucer and twin nacelles housed a crew of around eighty, and the ships relied on polarized hull plating rather than deflector shields for protection.
The first ship of the class, Enterprise (NX-01), launched in 2151 under Captain Jonathan Archer, its departure brought forward after a Klingon courier crash-landed on Earth. A second ship, Columbia (NX-02), launched in 2154 under Captain Erika Hernandez.
Enterprise's voyages produced first contacts with many species and a mission into the Delphic Expanse to stop the Xindi superweapon. The experience of the NX-class crews helped prepare the way for the Coalition of Planets and, later, the founding of the United Federation of Planets.