Upper air pressure and density measurements from 90 to 220 kilometers with the Viking 7 rocket

Abstract

The density and pressure of the atmosphere from 90 to 220 km above White Sands, New Mexico, were determined from the Viking 7 rocket flight on 7 August 1951 at 11:00 a.m. MST. A Philips ionization gage was used to measure pressure and pressure changes on the side of the nose cone of the rolling rocket. Measured pressure in the 90 to 105 km region were corrected for velocity ram and residual gas, and were approximately one-fourth of the Rocket Panel values. The derived pressure of 3×10−7 mm Hg at 220 km is twice the corresponding Rocket Panel value. Densities were measured from 120 to 185 km and at 220 km. The 220 km density value of 9×10−8 gm/m3 agrees with the Rocket Panel value. However, the density values at the lower altitudes are one-fourth to one-half those of the Rocket Panel. These lower density values in the 100 to 130 km region are in good agreement with values obtained from X-ray absorption experiments. Scale heights, (RT/Mg), derived from the density data above 140 km, are approximately a factor of two higher than Rocket Panel values.