Atmospheric density measurement in the middle atmosphere. Annual report 1 May 1976--30 June 1977. [20 to 90 km]

A density gauge for use in the 20-90 km range of the atmosphere was developed. It is based on beta-ray forward scattering and uses a Pm-147 beta source. Estimated accuracy is +- 6% or better for launch on an Arcas having apogee near 90 km. The flight model will be ready for integration into the Arcas by March, 1978. A flight program for the sonde is recommended, and techniques offering potential for application of the method up to 100 km are discussed.