High Altitude Observatories for Cosmic Rays and Other Purposes

Abstract

The original proof that cosmic radiation was of extra-terrestrial origin came from balloon flights made by Hess and others, in the early years of this century. Since the cosmic radiation was attenuated by the atmosphere, it was clear that to study this radiation one should go up as high as feasible. From the first, balloon flights were used, but these can carry only limited loads and have hard-to-control trajectories and flight characteristics. We discuss these below. Aircraft could not attain high altitudes in the early years and only since about 1940 have been much used for high altitude studies. For example, a flight made by the present author in 1936, in the original DC-2, broke the then South American altitude record, reaching over 30000 feet, and this record stood for a number of years.