Satellite measurements of neutral composition with a velocity mass spectrometer
Document ID: 311
Philbrick, C. Russell1
Narcisi, R. S.1
Baker, D W1
Trzcinski, E.1
Gardner, M. E.1
1 USAF, Cambridge Research Laboratories, Hanscom AFB, Bedford, MA, U.S.A.
Presented: Fifteenth COSPAR Meeting
Madrid, Spain, May 10-24, 1972
Abstract
A new instrument has been designed and successfully flown which is capable of measuring the atmospheric composition by energy analysis of an incoming stream of gas at satellite velocity. At satellite velocity the energies of several species are approximately H(0.3 ev), He(l.3 ev), O(5.3 ev), and N2(9.3 ev). The operating principle is based simply on the fact that electron bombardment ionization does not impart significant energy to the ion formed in the majority of the interactions and retarding energy analysis can be used to separate the ionized stream by mass. The ion source is a modification of the Pierce type which provides a uniform sheet of electrons through a field free ionization region. The instrument was flown on the OVl-21 satellite which was launched into an 780 x 920 km polar orbit on 7 August 1971. Real time data were obtained from the experiment for a period of one month. Sample spectra obtained from the instrument are shown and some of the details of the experiment are discussed. Preliminary results from the experiment which obtained measurements of He and O are presented.