This investigation utilizes a Solar Wind Ion Composition Spectrometer (SWICS) to determine the elemental and ionic composition, temperatures, and mean speeds of all major solar wind ions from H through Fe. The range of wind speed covered is 145 through 1350 km/s, and the energy/charge (E/Q) range is 110 eV/Q through 66.7 keV/Q. Collimated ions first enter an electrostatic analyzer and are post-accelerated, after exit, by a fixed 30-kV potential (V) into a time-of-flight (T) chamber and then into a solid state detector which measures the energy, E+V. From the measured values of E/Q, T, and E+V, the energy, charge, and mass of an entering ion are fully determined. The instrument has a mass of 5.6 kg, uses 3.6 W mean and 4.7 W peak power, and has a data rate of 44 bps in storage mode and 88 bps in tracking mode.