An Earth Starfleet ship of the 2150s, smaller than the NX class, that helped drive off the Klingon Duras as Enterprise reached home after the Xindi attack.
The Intrepid was one of the ships of Earth's Starfleet at the time of Enterprise NX-01, a smaller and slower design than the NX class, used for defence of the home system.
In The Expanse, Enterprise returns to Earth after the Xindi probe attack of 2153 with the Bird-of-Prey of the Klingon Duras in pursuit. The Intrepid and two other Starfleet ships come out to meet it and force Duras to break off.
The ship has a larger part in the alternate future of Twilight, where it is commanded by Captain Carlos Ramirez. After the Xindi destroy Earth, the Intrepid is one of the few ships left guarding the last human settlement on Ceti Alpha V.