Jupiter and its 67 moons might be regarded as a miniature Solar System. Knowing more about this gas giant, its powerful magnetic field and, most importantly, its four large 'Galilean' satellites is important for our understanding of certain fundamental processes in the Solar System. In 2022, ESA's JUICE (Jupiter icy moon explorer) will be launched for Jupiter, a mission in which DLR is strongly involved. Next to the planet itself, the mission will focus on three of its large moons, Ganymede, Callisto, and Europa. Under their thick ice shields, oceans of water are suspected to exist, and even life might have evolved there. The probe is scheduled to arrive at Jupiter in 2030. After three years of observation, JUICE will probably end in 2033.