High-energy radiations from space.

Survey of past, current, and planned U.S. high-energy astronomy observation (HEAO) experiments in space, and review of their significance. It is shown that astronomical observations from spacecraft during the first decade of space flight, though they be few and modest, have provided a wealth of new results that are most exciting, and that suggest that the next 20 or 30 years of space exploration may write a new chapter in the history of astrophysics and astronomy as important as the chapters initiated by Galileo or by the five-meter telescope on Mount Palomar. Special attention is given to the planned HEAO-A and HEAO-B experiment series.