In addition, you may want to check out AeroSpaceGuide. This site has some interesting facts as well as mission summaries.

The first probe to visit Jupiter was the Pioneer 10. This probe was the first probe to ever penetrate the Asteroid Belt. This probe was launched in May of 1972 and passed the orbit of Pluto in June of 1983.

Pioneer 11, identical to Pioneer 10, was launched in May of 1973. The encounter of Jupiter was in December of 1974 and a visit of Saturn occurred in September of 1979. Contact was lost in November of 1995.

The most infamous of all probes, the Voyager series, was also designed to study the gas giants. Voyager 2 (launched before Voyager 1) was launched in August of 1977. The Jupiter flyby was in July 1979, the Saturn flyby was in August 1981, the Uranus flyby was in January 1986, and the Neptune flyby was in August 1989. The Voyager 2 has left the Solar System but is still in operation.

The Voyager 1 probe, launched in September of 1977, would only visit Jupiter and Saturn. The Voyager 2 probe was launched first after discovering the orbital positions of all four gas giants would allow the probes visit. Voyager 1 was launched as planned.

The most remarkable Jupiter mission was the Galileo probe. Launched in October of 1989, this probe provided some of the best views of the moons of Jupiter, and also inspired a flurry of protest. The Galileo probe used planetary flyby's (including Earth) to adjust trajectory and velocity. The power plant within the probe uses radioisotope thermoelectric generators or RTG's which is nothing new. This type of power was also used in the Pioneer and Voyager series as well. The protest came in two forms:

• Concern over impact with Earth during its flyby
• Concern over burn-up in the Jupiter atmosphere

There was actually several doomsday programs here in the Bay Area voicing concerns over the probes intentional impact with the Jovian atmosphere. It was suggested that the RTG in Galileo would be enough to initiate nuclear fusion within the core of Jupiter. There are a few reasons why this is not possible:

• The amount of material in Galileo's RTG was depleted and not enough top produce an atomic weapon
• The core of Jupiter is rock, not hydrogen like the heart of a star
• While its been suggested Jupiter is a failed star, the lowest mass of a body that could initiate fusion is a body with 0.8 solar masses

The probe was burned up, safely, on September 21, 2003.

While not a Jupiter probe, the Ulysses is in a very elongated orbit to study the Sun. Its orbit passes Jupiter for the purpose of gravity assist.

Also not a Jupiter probe, the Cassini-Huygens probe past Jupiter on its way to Saturn. Some of the clearest images of Jupiter were produced by the Cassini-Huygens probe.

The Future:

There is only one mission planned for a return to Jupiter. Still in the design stages, Prometheus One will study Jupiter in depth and will also orbit three of its moons: Callisto, Ganymede and Europa. Continual study of the presence of water will be performs. The mission is only proposed and has not entered design stages so call your Congressman! Launch is proposed for 2015.

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