The study of the Solar System is fundamental to answer key questions from space agencies, as outlined in their strategic plans, about the content, origin, and evolution of the Solar System and the potential for life elsewhere. The UV spectral range is a crucial window to investigate a large area of phenomena associated with this objective, ranging from the surfaces to the atmospheres and magnetospheres of the Solar System bodies. In this White Paper, submitted to ESA in response to the Voyage 2050 call, we present a few examples of science issues that could be addressed about surfaces, atmospheres, and magnetospheres for different objects in the Solar System using UV observations. After the planned termination of the highly successful Hubble Space Telescope (HST), a new multi-objects UV observatory with UV spectro-imager to map the surfaces, atmospheres, and auroral regions of the different objects of the Solar System, and spectropolarimeter to provide measurements on the surface texture, atmospheric aerosols, surface pressure for KBOs, and magnetic field measurements, would be needed to answer the major questions presented in this paper and to open new possibilities of exploration in the Solar System and beyond.