Jupiter’s dominance of the solar system has led to many spacecraft missions, beginning with Pioneer 10’s 1973 flyby. A year later, Pioneer 11 passed the great planet. But sophisticated, close-up study of the giant planet began with the twin flybys of NASA’s Voyagers in 1979.
Voyager 1 and 2 increased our jovian knowledge immensely. They mapped the planet’s moons, took detailed images of Jupiter’s complex atmosphere, and even discovered a faint set of rings.
NASA's Galileo mission, which entered jovian orbit in 1995, gave scientists another windfall. Even as it approached Jupiter in 1994, Galileo witnessed one of the greatest events in solar system history — Comet Shoemaker-Levy 9’s spectacular crash into the giant planet. Galileo sent a probe plummeting into Jupiter’s atmosphere. The probe sampled the atmosphere directly and returned much information before immense pressure deep below Jupiter’s clouds crushed it. In 2003, at mission end, Galileo itself met the same fate.
In July 2016, NASA’s Juno spacecraft entered orbit around Jupiter to begin a new round of scientific observations. With Juno, researchers have precisely mapped Jupiter’s gravitational and magnetic fields, learned a great deal about the planet’s cluster of polar cyclones, and discovered that the gas giant surprisingly rotates like a solid body just below its chaotic cloud tops. Although Juno was initially slated to cease scientific operations in February 2018, the mission was recently extended and is now expected to run through July 2021.