Jupiters Great Red Spot (image courtesy NASA)The first probe to reach the gas giant, Jupiter, was Pioneer 10 on 3rd December 1973 with principal instruments measuring the magnetosphere and the atmosphere. A year and a day later it was followed by Pioneer 11.

The next to arrive was Voyager 1 in March 1979 followed in July by Voyager 2. The Voyagers discovered active volcanism on the moon Io.

In February 1992 Ulysses turned its instruments on Jupiter as it made a swing by to throw it into it’s solar polar orbit.

From December 1995 until 2003 the Galileo mission undertook a detailed study of the planet and it’s moons, including the sending of a probe into the atmosphere. It made many scientific discoveries including finding what is thought to be a liquid sea below the ice of Europa.

Jupiters moons (image courtesy NASA)

During this period, in December 2000, Cassini did a flyby on it’s way to Saturn