The Special Sensor Ultraviolet Limb Imager (SSULI) and Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instruments operate aboard the US Defense Meteorological Satellite Program Block 5D3 series satellites for space situational awareness environmental sensing. Ultraviolet remote sensors can specify space environment specification of both the ionosphere and the neutral atmosphere.
Combining simultaneous observations from complementary limb- and nadir-viewing sensors improves measurement resolution and signal-to-noise and enables full-orbit atmospheric reconstructions. High fidelity ionospheric reconstructions can accurately characterize atmospheric gradients to constrain DoD operational global ionosphere data assimilation models and increase the accuracy of slant-TEC values important for various ray-tracing applications. Space-based UV remote sensing is the only effective approach to provide neutral thermospheric composition, density, and temperature profiles on global scales. Operational space weather modeling is poised to move beyond nowcasting into forecasting using next-generation full-physics assimilation models. Since tomorrow’s ionosphere is better predicted by today’s neutral atmosphere than by today’s ionosphere, space-based UV sensors will be an essential data type for future physics-based global ionospheric assimilation model forecast. We present new full-orbit tomographic retrievals of UV emissions using limb and nadir UV sensors, which include the important feature of extinction along the lines-of-sight.