Exploring a planetary king
Exploration of Jupiter has seen much progress – not as much as Earth,
Mars or Venus, but it’s a close fourth. If a spacecraft can make it past the asteroid belt beyond Mars, then Jupiter is there to welcome it.
Jupiter has been able to act as a valuable gravitational slingshot, also known as a gravity assist, which takes advantage of its intense gravity to alter a spacecraft's speed or path.
The king of the Solar System has bestowed gravity assists to many spacecraft that aim to venture to the outer regions of our cosmic backyard, such as NASA’s Pioneer 10 and 11, the two Voyager spacecraft and the New Horizons mission, as well as NASA and the European Space Agency’s (ESA) Ulysses and Cassini-Huygens. The first to meet Jupiter was Pioneer 10 in 1973. It wasn’t just a slingshot that Jupiter gave these missions; it also gave them a chance to test their instrumentation ahead of their destination, and these tests sent back data on the gas giant.
There have also been two main missions sent to Jupiter, however. Engineers were able to place them into orbit and gather continuous information on the mysterious workings of the Jovian king.
On 8 December 1995, NASA’s Galileo spacecraft entered the orbit of Jupiter - and for nearly eight years - collected remarkable data about the planet and its moons, including observations of the
Comet Shoemaker-Levy 9 collision beginning on 16 July 1994 that revealed unknown details about the planet’s composition.
The second mission, still in operation, is NASA’s Juno. Equipped with a finely tuned instrumental suite, Juno has been studying the interior and exterior of Jupiter since its orbital insertion on 5 July 2016.
There are plans to head back to the Jovian system in the near future, but it is to study its Galilean moons, hopefully revealing the presence of subsurface oceans. ESA’s Jupiter Icy Moons Explorer (JUICE) and NASA’s Europa Clipper are due to begin their journeys in June 2022 and by 2025, respectively.