|Owner:||Mr. Mayweather sr.|
|Operator:||Earth Cargo Service|
In 2141, the Horizon encountered a Deltan ship. Travis Mayweather, who was fifteen at the time, described the Deltans as very attractive and very open. (ENT: "Bound") The Horizon once came under attack by Nausicaan pirates; it barely escaped in one piece. (ENT: "Fortunate Son")
In January 2153, the Horizon was attacked by the same pirates that attacked the ECS Constellation many weeks prior. Mayweather managed to upgrade the ship's plasma cannons by connecting them directly to the ship's impulse engines. This, combined with his expert piloting skills, allowed the Horizon to withstand the attack. (ENT: "Horizon")
Among the planets visited by the ECS Horizon were:
The assignment patch for the Horizon was created by Anthony Fredrickson, a design task provided to him by Michael Okuda. "Because this was the Horizon, I did a star dropping behind the horizon and an old-time sailing ship with a star glowing at the top of its mast," Fredrickson recalled. (Star Trek: Communicator issue 144, p. 36)
According to a deleted scene from "Fight or Flight", the Horizon made a two light year journey from a planet called Livinius to another called Belarn Prime when Mayweather was a child. The trip took the freighter almost nine months. The deleted scene can be found on ENT Season 1 DVD.
Although the capabilities of this vessel vastly limit its travel radius (not taking into account possible upgrades to its engines in the future), it has been suggested that this vessel may be the Horizon that discovered the planet Sigma Iotia II in 2168, an event established in TOS: "A Piece of the Action". This is believed, in part, due to the fact that the dialog from that episode never clarifies the origins of that Horizon, outside of being an Earth starship. In the episode, it is stated that the Horizon came "from the same outfit as" the USS Enterprise, but it is never specified if that "outfit" was Starfleet or another Earth agency. Interestingly, this connection to TOS was not lost on the set decorators of Enterprise – in "Horizon", a hard-bound copy of a book beginning with the title Chicago Gangs can be briefly glimpsed on a bookshelf in Travis' quarters aboard his old ship.
The Pocket ENT novel Kobayashi Maru states the ECS Horizon was the ship that visited Sigma Iotia II, as mentioned in "A Piece of the Action". The fate of the Horizon was unclear; by the end of the book it was deemed missing and presumed destroyed by Romulan action.