while the population of energetic protons trapped in the earth's radiation belt has been investigated in considerable detail, only a few experiments have been designed to search for heavy particles. We present in this report the first observations of alpha particle fluxes and pitch angle distributions at high altitudes (3.1 ≤ L ≤ 5.2) near the geomagnetic equatorial plane. Included in the scientific payload of the S3-A satellite is a heavy ion telescope, which measures the fluxes of ions with Z ≥ 2. This telescope consists of two surface barrier solid-state detectors of thickness 3.4 and 100 microns (μ). The properties of such thin detectors, including the S3-A 3.4-μ unit, are discussed in detail by Wilken and Fritz (unpublished manuscript, 1972). This telescope uniquely identifies the presence of alpha particles (Z = 2) and two groups of heavier ions, 3 ≤ Z ≤ 5 and 6 ≤ Z ≤ 8.