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Hydrogen, He and oxygen ion density, and ion and electron temperatures in upper ionosphere from OGO 4 observations

Lower ionosphere measurements at solar minimum, discussing positive ion density, electron density, solar radiation optical depth, etc

Identification of regions between 65 and 120 km by different loss mechanisms - study of lower ionosphere at solar minimum based on measurements by Nike-Apache rockets

Temperature of charged particles in upper atmosphere determined by direct measurements from rockets and satellites, electron scale heights, and ground-based radar

Satellite and rocket studies of neutral atmosphere and ionosphere with emphasis on charged particle motion in gravitational and electromagnetic fields

Ionospheric electron density profiles for D, E, and F layers

Rocket and satellite investigations of ionospheric electron and ion collision frequencies, solar radiation, D, E and F regions, plasma frequency probe, etc

Ionospheric research from space vehicles, comparing experimental data with theoretical models of D, E and F regions

Electron density and temperature, ion composition and density, and effects of solar corpuscular radiation in ionosphere - satellite drag measurements

Atmospheric heating deduced from satellite drag observations compared with intensity of extreme ultraviolet radiation

Charged particle temperatures in upper atmosphere

Low energy ion density in d-, e-, & f-regions of ionosphere

Structural analysis of upper atmosphere from rocket and satellite measurements of charged particles

Space vehicle research on ionospheric d, e, and f regions, studying disturbances in charge particle temperatures and densities

Upper atmosphere temperatures derived from charged particle observations

Electron temperature measurements on the explorer viii satellite

A review is made of ionospheric data reported since the IGY from rocket and satellite-borne ionospheric experiments. These include rocket results on electron density (RF impedance probe), D-region conductivity (Gerdien condenser), and electron temperature (Langmuir probe). Also included are data in the 1000 kilometer region on ion concentration (ion current monitor) and electron temperature from the Explorer VIII Satellite (1960 xi). The review includes suggestions for second generation experiments and combinations thereof particularly suited for small sounding rockets.

Experimental data were obtained from the Explorer VIII satellite on five parameters pertinent to the problem of the interaction of space vehicles with an ionized atmosphere. The five parameters are: photoemission current due to electrons emitted from the satellite surfaces as a result of solar radiation; electron and positive ion currents due to the diffusion of charged particles from the medium to the spacecraft; the vehicle potential relative to the medium, and the ambient electron temperature. Included in the experimental data is the aspect dependence of the photoemission and diffusion currents. On the basis of the observations, certain characteristics of the satellite's plasma sheath are postulated.

Two rockets were flown to peak altitudes of 220 km in September 1959 to test various methods planned for future measurements of ionization parameters in the ionosphere, exosphere, and interplanetary plasma. The experiments used techniques which sample the ambient environment in the immediate vicinity of the research vehicle. Direct methods were chosen since indirect propagation techniques do not provide the temperatures of charged particles, are insensitive to ion densities, and cannot measure local electron densities under all conditions. Very encouraging results have been obtained from a preliminary analysis of data provided by one of the two flights. A new rf probe technique was successfully used to determine the electron density profile. This was indicated by its agreement with the results of a companion cw propagation experiment, particularly when the probe data were corrected for the effects of the ion sheath which surrounds the vehicle. The characteristics of this sheath were determined directly in flight by an electric field meter which provided the sheath field, and by a Langmuir probe which measured the total potential across the sheath. The electron temperatures deduced from the Langmuir probe data are greater than the neutral gas temperatures previously measured for the same location and season, but these measurements possibly were taken under different atmospheric conditions. Ion densities were calculated from the ion trap data for several altitudes ranging from 130 to 210 km and were found to be within 20 percent of the measured electron densities.