The ExoCube mission is designed to measure upper atmospheric global in-situ densities of light ion and neutral species (M<40). The ExoCube launched on January 31st. 2015, from Vandenberg Airforce Base, on a Delta II into a near polar ~440 x 675 km orbit. The expected six-month minimum mission lifetime will facilitate characterization and equinox-solstice comparison of the following key scientific objectives to be investigated:
- Upper atmospheric global, diurnal, and seasonal variability
- O-H charge exchange processes
- Atmospheric responses to geomagnetic storms
- Validation of empirical and climatological atmospheric models
- Constraint of aeronomical parameters of interest from airglow observations to forward radiative transfer modeling
The dual ion and neutral mass spectrometer (MS) on ExoCube was designed at Goddard Space Flight Center (GSFC), and weighs less than 1kg and uses under 2W power. It has a 20˚ field-of-view for the detection of ambient upper atmospheric fluxes that are predicted by MSIS. The neutral aperture includes an ion repeller and an ionization chamber where fluxes may be attenuated as necessary. Ionized neutrals and ions are accelerated by a ~200 Volt separation grate after which the gated time-of-flight (TOF)/ electrostatic analyzer (ESA) detector bins the TOF spectra corresponding to mass.
The TOF-MS instrument measures ion and neutral spectra continuously with a 1 second time resolution, generating data at 1.6kB/spectrum. The spacecraft then stores selected data on a 16Gb radiation hardened solid state disk before transmitting to the ground station during overpasses.
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