For the first time ever an irradiation test was performed on a complete satellite. This was made possible by the use of the CERN CHARM facility which allows testing full systems thanks to the widespread radiation field in the irradiation room. In addition, the CHARM facility allows replicating the particle spectra environment of the Earth's proton radiation belt, which is the most critical for LEO missions, with a high acceleration factor. This satellite, named Celesta, was realized as joint collaboration among CERN, Université de Montpellier and ESA. Its payload is a small-size replica of the RadMon, the radiation monitor which is used in many LHC installations.