Neutral gas composition of the upper atmosphere by a rocket-borne mass spectrometer

Abstract

This is a preliminary report on the night-time flight of a mass spectrometer designed to investigate the composition of the upper atmosphere. From 113 km altitude to 141.6 km, the peak of flight, on the ascent of the rocket, and from 141.6 km to 74 km on the descent, the spectrometer detected the usual constituents of air. In the vicinity of 85 km on the descent, components with mass number 46 and 23 were detected and are tentatively identified as nitrogen dioxide and sodium, respectively. The Bennett-type radio-frequency mass spectrometer was flown in Aerobee NRL-28 at 2200 MST, December 12, 1955, from White Sands Proving Ground, New Mexico. Mass spectra between 56 and 6 atomic mass units of the ambient atmospheric gas were obtained. The experiment was similar to that in Aerobee NRL-13 previously reported,1 except that increased resolution was obtained by use of a four-stage spectrometer tube and that the nose-tip of the rocket was thrown off, exposing the evacuated spectrometer tube directly to the atmosphere. Due to an instrumental difficulty, the electron emission in the ion source was less than 10 per cent of normal and peak amplitudes were generally small.