Juno was NASA’s spacecraft that entered orbit around Jupiter in 2016 to study the planet’s interior.
Juno launched on 5 August 2011 and reached Jupiter on 4 July 2016. It travels in a highly elongated polar orbit, allowing its instruments to pass close over the cloud tops and avoid spending most of the mission inside Jupiter’s intense radiation belts.
The spacecraft measures Jupiter’s gravity and magnetic fields, maps its deep atmosphere, and investigates how the planet formed. Its observations revealed complex polar cyclones, a powerful and irregular magnetic field, and evidence that Jupiter’s core is more diffuse than scientists had expected.
Juno is powered by solar panels, unusual for a spacecraft operating so far from the Sun. Galileo was NASA’s earlier Jupiter orbiter, operating from 1995 to 2003, but it followed an equatorial orbit and ended by entering Jupiter’s atmosphere.