THE IO VOLCANO OBSERVER (IVO): FOLLOW THE HEAT!

IVO, a NASA Discovery mission concept for exploring Jupiter’s volcanic moon Io, will focus on understanding tidal heating as a fundamental planetary process. In an inclined Jupiter-centric orbit, IVO will make at least ten close flybys of Io. Science instruments include a narrow-angle camera, thermal mapper, magnetometers, plasma instrument, neutral mass spectrometer, and we hope to add a wide-angle stereo camera as a student collaboration instrument. Our mission is to “Follow the Heat”, from generation of tidal heat, transfer through the body, and loss at the surface through volcanism. Tidal heating is especially relevant to the early Earth–Moon system, tidally-heated ocean worlds, and exoplanets (e.g., TRAPPIST-1). How and where tidal energy is dissipated depends on and controls the distribution of melt in Io’s mantle. Either Io’s mantle is predominantly solid and heat is generated by dissipation and partial melting in the shallow and/or deep mantle, or Io’s interior includes a layer of abundant (>20%) silicate melt, perhaps a magma ocean that mechanically detaches the lithosphere. IVO’s magnetic sounding, gravity science, optical geodesy to measure libration amplitude, and global survey of heat flow, active volcanoes, and lava compositions and temperatures will distinguish between these hypotheses. IVO will also test and refine the volcanic heat pipe model, perhaps a fundamental heat-loss tectonic style (along with conduction and plate tectonics) that was important in the early evolution of the Earth, Moon, and other planets. The Laplace resonance links the thermal and orbital evolution of Io, Europa, and Ganymede; thus Io is a critical to understanding the system. For example, precise astrometry of Europa and Ganymede (from JUICE and Europa Clipper) is of little value without comparable measurements of Io. Another goal of IVO is to understand loss of volatiles as a step towards understanding how Io is evolving over time.