Lower thermosphere studies from tether

Experiments planned for a low-altitude tethered satellite mission, which is being planned for studies on the composition, concentrations, and wave structure of the neutral and ionized components of the lower thermosphere (i.e., from 100 to 130 km heights), are discussed. One goal of these studies is to measure total hydrogen content (H, H2, H2O, and CH4) and use these data to improve the estimate of the global escape flux of hydrogen. The instrument that is being designed for this purpose is a neutral gas/ion magnetic sector mass spectrometer that has a mass range that extends from 2 through 65 amu in its three channels, and has a retarding voltage (RV) grid incorporated into the ion beam path within the instrument. The RV grid will be used to separate ambient gas molecules from contaminant species, and in the analysis of the distribution velocity of the ambient gas molecules along the satellite flight path.