An experimental study of the interaction of heavy, highly charged, and energetic ions (52 MeV 58 Ni 13+ ) with pure H 2 O, pure CO 2 and mixed H 2 O:CO 2 astrophysical ice analogs is presented. This analysis aims to simulate the chemical and the physicochemical interactions induced by heavy cosmic rays inside dense and cold astrophysical environments, such as molecular clouds or protostellar clouds. The measurements were performed at the heavy ion accelerator GANIL (Grand Accélérateur National d'Ions Lourds in Caen, France). The gas samples were deposited onto a CsI substrate at 13 K. In-situ analysis was performed by a Fourier transform infrared (FTIR) spectrometer at different fluences. Radiolysis yields of the produced species were quantified. The dissociation cross sections of pure H 2 O and CO 2 ices are 1.1 and 1.9 ×10 −13 cm 2 , respectively. For mixed H 2 O:CO 2 (10:1), the dissociation cross sections of both species are about 1 × 10 −13 cm 2 . The measured sputtering yield of pure CO 2 ice is 2.2 × 10 4 molec ion −1 . After a fluence of 2−3 × 10 12 ions cm −2 , the CO 2 /CO ratio becomes roughly constant (∼0.1), independent of the initial CO 2 /H 2 O ratio. A similar behavior is observed for the H 2 O 2 /H 2 O ratio, which stabilizes at 0.01, independent of the initial H 2 O column density or relative abundance.