NASA’s Juno spacecraft has been orbiting Jupiter since 2016. It entered orbit on July 4, 2016, after a nearly five-year journey from Earth, becoming the first spacecraft designed to study Jupiter primarily from a polar orbit.
Juno investigates the planet’s deep atmosphere, powerful magnetic field, auroras, gravity, and internal structure. Its measurements help scientists understand how Jupiter formed and how the early solar system developed. The spacecraft’s orbit carries it close to Jupiter’s cloud tops before taking it far away, reducing the time it spends in the planet’s intense radiation belts.
A common mix-up is Galileo, which also orbited Jupiter, but much earlier: NASA’s Galileo spacecraft entered orbit in 1995 and operated until 2003. Voyager and Cassini performed Jupiter flybys rather than becoming long-term Jupiter orbiters. Juno is powered by solar panels, an important engineering achievement because Jupiter receives much less sunlight than Earth.