NASA launched the Juno probe to Jupiter

On August 5, 2011, NASA’s Juno spacecraft lifted off from Cape Canaveral aboard an Atlas V 551 rocket, beginning a five-year, roughly 1.7-billion-mile journey to the solar system’s largest planet.

Juno was built to peer beneath Jupiter’s swirling clouds rather than just photograph them. Its instruments map the planet’s gravity field, magnetic field, and deep atmosphere to reveal how much water it holds and whether it hides a solid core. The answers bear on a bigger question: how Jupiter, and the planets around it, first came together.

Juno reached Jupiter on July 4, 2016, slipping into a looping polar orbit that skims just above the cloud tops.

Running on three giant solar arrays rather than nuclear power, Juno proved that a spacecraft could gather sunlight even five times farther from the Sun than Earth. Its findings since suggest Jupiter’s core is diluted and fuzzy rather than neat and compact.