Implementation of real-time high-resolution extended EUV solar spectral irradiance forecast

ABSTRACT: Thermospheric densities are critical in determining orbital drag for providing collision avoidance warnings for manned and unmanned spaceflight, accurately cataloging orbiting objects, predicting reentry times, and estimating satellite lifetimes, on-board fuel requirements, and attitude dynamics. One of the critical drivers to thermospheric density models is the extreme ultraviolet (EUV) solar spectral irradiance (SSI), and shortfalls in satellite drag prediction have been, in large part, due to inadequate prediction capability of the EUV SSI variations. This proposal is to provide forecasts of one of the most important drivers of neutral density variations, and thereby provide more accurate prediction of satellite drag than what is currently available. The Solar EUV Radiation Forecast System (SERFS) produces the best available forecast by using near- and far-side images of the solar surface to determine the distribution and evolution of the active regions, and previously computed emitted spectra from the components. SERFS combines the most recent detailed observations of the sources of the solar radiation spectrum with the previous knowledge of these sources. The technique has been demonstrated and the work in Phase II shall produce an operational prototype for forecast of indices and EUV spectra useful for existing and future thermospheric and ionospheric forecast modeling. BENEFIT: The daily forecasts produced by SEFS will substantially improve existing empirical thermospheric forecasts using the JB2008 indices and other indices, sophisticated thermospheric forecast modeling based on Global Circulation (GCM), and make possible even more sophisticated physical modeling in the future. Commercial applications of the SERFS operational system are expected to be of interest to US government agencies concerned with space operations such as the USAF and NASA, collaborative science teams and 3rd party engineering application Value-Added Resellers, and the science and engineering communities in physical modeling solar influences on the thermosphere and ionosphere. When the physical forecast modeling acquires maturity, we expect that operations by government agencies and satellite operators will migrate from the empirical to the physical models and utilize the full spectrum UV SSI that SERFS provides by using to the fullest potential the existing and future solar imaging and spectral observations. Keywords: Solar Spectral Irradiance, Solar Extreme Ultraviolet, Thermospheric Modeling, Ionospheric Modeling, SSI Variations, EUV Forecast.