We propose to observe the Jupiter Satellites Europa, Callisto and Ganymede and 
the Saturn satellite Iapetus in order to search for atmospheric components. 
Recent Galileo observations (Kliore et al., Barth et al.) have shown that 
atmospheres exists at least on Europa and Ganymede and also suggest that similar
 
processes, interactions of charged particle radiation with water ice, should be 
observable at Callisto as well. On all targets we expect some mixtures 
consisting of H2O, H, OH, O2, O, SO2 and O3. The observations will provide 
answers on the respective abundances and their mixing ratios.