High energy astrophysical observations supported by the National Aeronautics and Space Administration will be conducted primarily from the Small Astronomy Satellites (SAS) and the High Energy Astronomy Observatories (HEAO). At the present time, three Small Astronomy Satellites have been approved for flight. The first (SAS A) will carry a set of collimated proportional counters to conduct a high sensitivity, high spatial resolution, all sky survey for X-ray sources, to search for temporal variations in the source intensity, and to measure the spectral distribution of sources in the energy range 1 to 20 keV. The spacecraft will carry two collimator systems of 1 by 10 deg and 10 by 10 deg fullwidth. The proportional counters are gas-filled beryllium window tubes. SAS A is planned for launch in late 1970.