To unlock the secrets of Io's volcanism and, therefore, the story of the formation and evolution of the jovian system, observations must continue to extend the time-series data that have proven to be so valuable up to now. Taking a broader view, no other body in the Solar System is subject to as much tidal heating as Io, but tidal heating does play an important dynamic role in heating other planetary satellites, such as Europa and Enceladus. To better understand the process, it is therefore logical to study Io, where tidal heating is at its most extreme. Observations of Io can be made from spacecraft and from telescopes, both on the ground and in space. It will be interesting to see how Io changes over the next 20, 50, and 100 years in observations at increasing temporal and spatial resolutions.

Spacecraft observations

At the time of this writing, the only high-spatial-resolution spacecraft observations of Io that are likely in the next decade will be in February, 2007 from the NASA New Frontiers Program New Horizons spacecraft, as it passes at high velocity through the jovian system on its way to a rendezvous with Pluto in 2016. The following is a description of planned Io observations as presented by John Spencer, a New Horizons Science Team Member, at a meeting of the ad hoc Io Working Group in June, 2006.