2.0.0 spase://SMWG/Instrument/AE-E/NACE Neutral Atmosphere Composition (NACE) NACE 2019-05-05T12:34:56Z This experiment measured in situ the spatial distribution and temporal changes of the concentrations of the neutral atmospheric species. In addition, new insight into in situ measurement techniques was obtained from comparisons of these measurements with those obtained from other onboard experiments; namely, open source spectrometer (75-107A-07), solar EUV spectrometer (75-107A-06), and atmospheric density accelerometer (75-107A-02). The mass-spectrometer sensor had a gold-plated stainless steel thermalizing chamber and ion source, a hyperbolic rod quadrupole analyzer, and an off-axis electron multiplier. When operating in the "normal" format, the analyzer measured all masses in the range 1 to 44 atomic mass units with emphasis on hydrogen, helium, oxygen, nitrogen, and argon. Another format was optimized for minor constituent studies of gas species in the measured range. Spatial resolution was determined primarily by the mode of spacecraft operation. In orbit, the presealed spectrometer was opened, and the atmospheric constituents passed through a knife-edged orifice into the thermalization chamber and ion source. Selected ions left the quadrupole analyzer through a weak focusing lens and were accelerated into an electron multiplier, where they were turned 90 deg to strike the first dynode. The spectrometer had a resolution of better than 1 u for all masses between 1 and 44, and the measurement system had a planned dynamic range of approximately 1.E8. There was provision for the instrument orifice to be covered during spacecraft thruster operations. More experiment details can be found in D. T. Pelz et al., Radio Sci., v. 8, n. 4, p. 277, 1973. spase://SMWG/Person/Alan.E.Hedin PrincipalInvestigator NSSDC's Master Catalog https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1975-107A-08 Information about the Neutral Atmosphere Composition (NACE) experiment on the AE-E mission. Radio Science Journal Article https://onlinelibrary.wiley.com/doi/abs/10.1029/RS008i004p00277 Detailed information about the neutral-atmosphere composition experiment on the AE-E mission. MassSpectrometer Neutral Atmosphere Composition (NACE) on AE-E spase://SMWG/Observatory/AE-E