Jupiter Has Been Visited 8 Times By Spacecraft
By using automated spacecraft to make up-close studies, Jupiter has been explored. It started in 1973 with the entry of Pioneer 10 into the Jovian system and has since continued with eight further spacecraft missions as of 2016. The National Aeronautics and Space Administration (NASA) carried out each of these missions, and all but two were flybys that collected extensive data without making a landing or entering orbit. Since all missions to the outside Solar System have employed flybys of Jupiter, this makes Jupiter the Solar System's outer planet that has been visited the most. The second spacecraft to ever accomplish so, Juno arrived and entered the planet's orbit on July 5, 2016. Large fuel consumption and the impacts of Jupiter's severe radiation environment are the main reasons why sending a probe there is challenging.
Pioneer 10 was the first spacecraft to reach Jupiter in 1973, and Pioneer 11 followed a year later. The probes not only captured the planet's first up-close images but also its magnetosphere and mainly fluid interior. The Voyager 1 and Voyager 2 spacecraft visited the planet in 1979 and investigated its moons and ring system, learning about Io's volcanic activity and Europa's water ice blanket. Ulysses conducted additional research on Jupiter's magnetosphere in 1992 and 2000. In 2000, as the Cassini spacecraft got closer to the planet, it captured incredibly precise pictures of its atmosphere. Improved measurements of Jupiter's characteristics and those of its satellites were made in 2007 by the New Horizons spacecraft when it sailed by Jupiter.
The first object to orbit Jupiter was the Galileo spacecraft, which arrived in 1995 and continued to observe Jupiter until 2003. Galileo obtained a lot of data about the Jovian system at this time by making near passes to all four of the major Galilean moons and discovering evidence of thin atmospheres on three of them as well as the potential for liquid water beneath their surfaces. A magnetic field was also found to surround Ganymede. It also witnessed the collision of Comet Shoemaker-Levy 9 as it got closer to Jupiter. It was the only spacecraft to accomplish so up until that point, sending an atmospheric probe into the Jovian atmosphere in December 1995.
