The spacecraft that flew by and photographed all four gas giants (Jupiter, Saturn, Uranus, and Neptune) is Voyager 2.

Here's a timeline of its flybys:

* Jupiter: July 9, 1979

* Saturn: August 25, 1981

* Uranus: January 24, 1986

* Neptune: August 25, 1989

Voyager 2 is still operating and is currently the farthest human-made object from Earth.