Which spacecraft made the first flyby of Neptune in 1989?

Voyager 2 made the first spacecraft flyby of Neptune on 25 August 1989.

NASA launched Voyager 2 in 1977 to study the outer planets. Its carefully planned trajectory used gravity assists at Jupiter, Saturn, and Uranus before carrying it onward to Neptune. During the encounter, the spacecraft photographed Neptune’s atmosphere, rings, moons, and the Great Dark Spot, a huge storm system.

Voyager 2 remains the only spacecraft to have visited Neptune at close range. Its observations revealed active weather, powerful winds, a faint ring system, and the unusual moon Triton, which has nitrogen geysers and a retrograde orbit.

Voyager 1 followed a different trajectory after Saturn and headed toward interstellar space, so it never flew past Neptune. Voyager 2’s Neptune encounter completed the first spacecraft tour of all four giant planets.