2.3.1 spase://CNES/Instrument/CDPP-AMDA/MAVEN/NGIMS NGIMS Neutral Gas and Ion Mass Spectrometer 2017-03-01T22:37:00Z The Neutral Gas and Ion Mass Spectrometer (NGIMS) measures the composition and isotopes of thermal neutrals and ions. Goals: *Determine structure and variation of neutral atmosphere and ionosphere with altitude over the globe from the homopause to above the exobase where the neutral gas can escape *Provide a basis for the study of thermospheric energetics, transport, circulation and formation of the ionosphere *Reveal the effects of lower atmospheric effects on the composition of the upper atmosphere and escape Observations: *Basic structure of the upper atmosphere (major species He, N, O, CO, N2, NO, O2, Ar, and CO2) and ionosphere from the homopause to above the exobase *Stable isotope ratios, and variations Technical details and heritage: *Quadrupole Mass Spectrometer with open and closed sources *Open source: neutrals and ions *Closed source: non-reactive neutrals *Mass Range: 2 – 150 Da *Mass Resolution: 1 Da *Modes: scan entire spectra or adapt to fixed masses *Sensitivity: 10-2 (counts/s)/(particles/cm-3) *Heritage from Galileo GPMS, Pioneer Venus ONMS, CASSINI INMS, Contour NGIMS spase://SMWG/Person/Paul.R.Mahaffy PrincipalInvestigator NGIMS web page, Summary sheet http://lasp.colorado.edu/home/maven/science/instrument-package/ngims/ MassSpectrometer 2013-11-18T13:28:00 Mars arrival : 2014-09-28T19:24:00 spase://CNES/Observatory/CDPP-AMDA/MAVEN