Abstract：Since 2012, the European Space Agency is working on a L-class mission for exploration of Jupiter system, with focus on Ganymede, Europa, and Callisto. The broader science topics revolve around life and habitability in the Solar System: Exploring in situ the surface and subsurface of the solid bodies in the Solar System that are most likely to host – or have hosted – life.  In this talk I will focus in particular on the Submillimetre Wave Instrument being developed at Max Planck Institute for Solar System Research; the science on Jupiter and the icy moons.