Study of the lower ionosphere using a rocket-borne riometer

A rocket-borne riometer was used to derive the electron density profile by measuring the changes in cosmic noise absorption in the lower ionosphere. Two additional experiments have been included in the same payload to measure electron density, a propagation experiment and a Langmuir probe. The principle and feasibility of the new technique are described and the instrumentation and the design considerations are discussed. The flight performance and data analysis are presented. It is found that the changes in cosmic noise absorption with altitude are consistent with the absorption changes measured by the propagation experiment in the 60-80 km altitude region. Above 85 km altitude the large electron densities cause impedance changes of the riometer-antenna. The antenna detuning is utilized to estimate the electron densities in this region.