The Effects of Spacecraft Potential on Ionospheric Ion Measurements

The energetic electrostatic analyzer has been developed to act as a miniaturized, rugged, and low-cost instrument capable of providing in situ measurements of ion or electron energy and subsequent derived density, temperature, and spacecraft potential. We present laboratory calibration results using a magnetically filtered low-Earth-orbit plasma simulator to quantify the effects of spacecraft charge on laminated analyzer ion energy distribution measurements and the resulting impact on the derived temperature and density values. The calibration results are then applied as an empirical correction method to Space Test Program Satellite-3 integrated miniaturized electrostatic analyzer data to present corrected temperature and density values. Application of the empirical correction factor improved the agreement between in situ measurements and the international reference ionosphere model in terms of ion temperature by 0.01 eV and in terms of density to within 20%.