Io (moon) - Observational History - Subsequent Observations

Subsequent Observations

Following Galileo's deliberate demise in Jupiter's atmosphere in September 2003, new observations of Io's volcanism came from Earth-based telescopes. In particular, adaptive optics imaging from the Keck telescope in Hawaii and imaging from the Hubble telescope have allowed astronomers to monitor Io's active volcanoes. This imaging has allowed scientists to monitor volcanic activity on Io, even without a spacecraft in the Jupiter system.

The New Horizons spacecraft, en route to Pluto and the Kuiper belt, flew by the Jupiter system and Io on February 28, 2007. During the encounter, numerous distant observations of Io were obtained. These included images of a large plume at Tvashtar, providing the first detailed observations of the largest class of Ionian volcanic plume since observations of Pele's plume in 1979. New Horizons also captured images of a volcano near Girru Patera in the early stages of an eruption, and several volcanic eruptions that have occurred since Galileo.

There are currently two forthcoming missions planned for the Jupiter system. Juno, launched on August 5, 2011, has limited imaging capabilities, but it could provide monitoring of Io's volcanic activity using its near-infrared spectrometer, JIRAM. The Jupiter Icy Moon Explorer (JUICE) is an European Space Agency mission to the Jupiter system that will end up in Ganymede orbit. JUICE has a launch scheduled for 2022 with an arrival at Jupiter planned for January 2030. JUICE will not flyby Io, but it will use its various instruments, such as a narrow-angle camera, to monitor Io's volcanic activity and measure its surface composition during the two-year, Jupiter-tour phase of the mission prior to Ganymede Orbit Insertion. The Io Volcano Observer was a proposal for a Discovery-class mission that would launch in 2015. It involved multiple flybys of Io while in orbit around Jupiter; however, this mission was not selected for Phase A study by NASA, and remains a mission concept.