Analysis of tectonics and cryovolcanism on Ganymede: possible observations with JGO-EJSM

Voyager data revealed that the Jovian moon Ganymede, the biggest satellite in the solar system, consists of ancient heavily cratered dark terrain and younger resurfaced and tectonically deformed bright terrain (groove lanes and polygons). These terrains seem to have undergone an intense resurfacing and several models were developed. However both Voyager data and successively in 1996 Galileo SSI (Solid State Imager) images did not have a spatial resolution high enough to define the most likely resurfacing phenomena. In particular Galileo data coverage is not global (fig. 1) and there is a great heterogeneity in the spatial resolution going from more than 500 m/pixel in some areas to 100 m/pixel in a very few areas. The WAC (Wide Angle Camera), which should be on board the ESA mission JGOEJSM, will provide a global coverage of Ganymede's surface with a constant spatial resolution of 150 m/pixel to perform in-depth geologic studies. Fig. 1: Plot of the resolutions of image data across the surface of Ganymede (Patterson et al. 2010 [3]). Higherresolution data: dark tones < 0.5 km/pixel, lower resolution data: light tones >5 km/pixel.