Rocket measurments of the upper lonosphere by a radio propagation technique

High altitude measurements of the electron density distributiom have been performed well above the F2 peak of the ionosphere by using. the two-frequency rocket-borne propagation experiment of Seddon. An example of a measurement of the electron-density profile up to 620 km by means of the c.w. propagation technique is presented, including the inferred scale height and temperature of the upper ionosphere. For the anticipated measurements up to an altitude of one earth radius using. the c.w. propagation experiment, the variation of the ionosphere below a vehicle must always be considered in order to arrive at reliable locat electron density data. A correction for this time variation can be made by using recorded information on the ordinary and extraordinary propagation modes at two harmonically related frequencies. This correction procedure is briefly outlined.