NASA's Juno spacecraft has successfully completed its extensive mission to explore Jupiter and its moons, concluding its operational life as of September 2025. Launched in 2011, Juno arrived in Jupiter's orbit in 2016. Its mission, initially planned for a shorter duration, received multiple extensions, most recently through September 2025, allowing for in-depth investigations of the Jovian system.
During its mission, Juno conducted close flybys of Jupiter's major moons, including Ganymede, Europa, and Io. These encounters provided critical data on the moons' geology, atmospheres, and chemical compositions. Ganymede, the solar system's largest moon, was studied for its grooved terrain and potential subsurface ocean. Juno also measured the rate of oxygen production on Europa, finding it to be approximately 12 kilograms per second, a figure lower than some prior estimates. For Io, the most volcanically active body in the solar system, Juno gathered data suggesting its volcanoes are powered by individual magma chambers.
The spacecraft also meticulously studied Jupiter's subtle ring system, offering new perspectives on its composition and formation. Furthermore, Juno mapped Jupiter's magnetic and gravitational fields with exceptional precision, revealing insights into its complex internal structure and a dilute core. In April 2025, Juno briefly entered safe mode during its 71st close flyby due to Jupiter's intense radiation, a known hazard, but mission control successfully restored operations.
The vast amount of data collected by Juno over nearly a decade has significantly expanded our understanding of Jupiter's atmosphere, magnetosphere, and its system of satellites. These findings are instrumental for future missions, such as NASA's Europa Clipper, which is scheduled to arrive at Jupiter in 2030. Juno's discoveries have challenged existing theories on Jupiter's formation and evolution, contributing to a deeper comprehension of our solar system's origins. The data gathered will continue to inform scientific research for years to come.