The experiment Sileye-3/Alteino is constituted by a cosmic-ray silicon detector and an electroencephalograph. The main scientific aims include the investigation of the Light Flash phenomenon, the study of astronaut brain activity in space when subject to cosmic rays, the measurement of cosmic rays and the radiation environment inside the International Space Station. The experiment was operating on board the station from 27 April to 5 May 2002. The cosmic-ray detector is composed of eight silicon strip planes triggered by two scintillators placed on top and bottom of the stack. The detector is capable of identifying nuclei from B to As in the energy range above ≃60 MeV/n. Also protons and lighter particles are registered although with a reduced efficiency. The instrument was active in the Pirs module of the station for 130 h. In this work, we describe the silicon strip detector characteristics and its calibration performed using cosmic-ray nuclei.