What spaceships have been to Neptune?

Answer 1

Voyager 2.

There haven't been any specific space probes sent to Neptune for mapping or exploration, like Cassini for Saturn and Galileo for Jupiter. However, the Voyager 2 space probe passed by Neptune in 1989 on its way out of the solar system and sent back pictures and information showing it to be an odd planet indeed.

Voyager 1 and 2 were originally programmed to visit Saturn and Jupiter, but Voyager 2's trajectory was altered to visit Neptune and Uranus also, and remains the only spacecraft to have visited either planet. (Voyager 1 was flown past Saturn's moon Titan instead.)

The Voyager Interstellar Mission, controlled by the Jet Propulsion Lab in Pasadena, CA, is still in contact with the Voyager spacecraft via the Deep Space Network, a huge array of globally interlinked radio telescopes that use their combined capability to communicate with them.

Answer 2

To date, no spacecraft has been to Neptune. However, the Voyager 2 spacecraft performed a flyby of Neptune in 1989, providing valuable data and images of the planet and its moons. The New Horizons spacecraft, known for its Pluto flyby, is currently on its way to explore other objects in the Kuiper Belt and beyond, but it is not scheduled to visit Neptune.