Juno Mission Nearing Io, Jupiter's Moon.

NASA's Juno spacecraft will fly past Jupiter's volcanic moon Io on May 16, marking the closest flyby to date at an altitude of about 22,060 miles. Juno has performed 50 flybys of Jupiter and collected data during close encounters with three of the four Galilean moons. Io is the most volcanic celestial body in our solar system, and Juno's sensors will study its volcanoes and how volcanic eruptions interact with Jupiter's powerful magnetosphere and auroras.