Enhancement of the Geomagnetic Cutoff Models inside SIRE2 (SIRE2-Real)

The Space Ionizing Radiation Environment and Effects (SIRE2) toolkit was developed to provide the space radiation environment and effects community with state-of-the-art models that can be used not just for satellites but also for arbitrary trajectories. In this Phase II effort, the SIRE2-Real capabilities will be tested and integrated into the SIRE2 toolkit. SIRE2-Real will provide benchmarking of space environments to historical measurements and spacecraft anomalies. The SIRE2-Real capabilities will allow the user to select a historical time range for SIRE2-Real to determine the peak flux, flux-time series, and mission-integrated fluence for the solar energetic particle (SEP) environment. SIRE2-Real will also use the historical Dst value for the geomagnetic activity at Earth during the userrsquo;s historical time range and be able to perform geomagnetic cutoff calculations using the historical International Geomagnetic Reference Field (IGRF) epoch that is closest to the userrsquo;s mission.The Mission Specific Solar Radiation Environment Model (MSSREM) and the Smart-Shea 2022 geomagnetic cutoff model will need to be updated, tested, and integrated into SIRE2 to provide the SIRE-Real capability. The MSSREM model will provide the user with historical peak flux, flux time series, and mission-integrated fluence for a userrsquo;s mission. The Smart-Shea 2022 geomagnetic cutoff model will need to be extended to allow the user to select between multiple IGRF epochs in the calculation.The Fifth Gait team will also be looking to enhance the geomagnetic cutoff models inside of SIRE2. The first thing that will be examined is the use of the 20 km vs 450 km world cutoff grids in the Smart-Shea model to determine if there is any significant difference between using the two different grids. Penumbral transparencies and analysis of the October 20, 1989 shock interval are other areas of improvement in the geomagnetic cutoff models that will be examined during the Phase II effort.