High-Altitude Measurements of X Rays and Far Ultraviolet Radiation

Since 1946, the Naval Research Laboratory has conducted basic research in the physics of the upper atmosphere by means of high-altitude rockets. The program has emphasized all areas of research, including atmospheric structure and composition, the ionosphere, airglow and aurora, meteors, cosmic rays, and rocket astronomy. In the last area, which includes X ray and ultraviolet radiation measurements, NRL scientists have contributed a major portion of the experimental information available today. These comprise all the existing data on solar X rays, the X ray and ultraviolet emissions of solar flares, the first spectrogram of the sun covering the ultraviolet region below 3000 A and subsequent extensions of the spectrum into the extreme ultraviolet, the first quantitative measurements of solar Lyman-α, and the discovery of ultraviolet nebulosities and the Lyman-α glow of the night sky. A recent success in photographing the profile of Lyman-α with very high resolution opens the way to the use of optical resonance absorption as a gauge of atmospheric composition. This method may prove to be a most powerful technique for analysis of the very high atmosphere, well beyond the range of satellite drag measurements. The purpose of this paper is to describe the experimental approach used in accomplishing the radiation measurement program just outlined.