Voyager 3, a probe made with the exact purpose of reaching outer space and explore beyond the solar system. To achieve this objective the probe had a nuclear based propulsion system, with a fusion based main propeller and a fission based ignitor which also served as an auxiliary engine.

However, during the maneuver to reach full speed, a combination of events caused it to switch dimensions and to impact with Equestria…interacting with it's magic field in a way not even Discord ever thought of…

Equestrians and humans alike started coming together…for the better and for the worse…