DREAM: An integrated space radiation nowcast system for natural and nuclear radiation belts

The natural space environment continues to surprise us. We recently witnessed the quietest solar minimum in the past 100 years, casting huge uncertainties on our expectations for approach to Solar Maximum. The overall space environment is made up of many related but independent parts. The Dynamic Radiation Environment Assimilation Model (DREAM) focuses on the spacecraft charging environment. DREAM-RB (Radiation Belt) covers the internal charging (penetrating radiation) environment and DREAM-RC (Ring Current) covers the external, surface charging environment. A third component of DREAM is an electron source model (ESM) that calculates the trapped electron environment produced by high altitude nuclear explosions (HANE). All three major components of DREAM have undergone accelerated development over the past 18 months and now comprise an integrated code system for realtime “nowcasting”, for retrospective analysis of events, and for assessing threats from nuclear scenarios. DREAMESM has many similarities to the legacy SNRTACS code system but was developed to give us a modern code architecture with well-understood physics that could be integrated into the full DREAM system. The core of that system is the radiation belt model that uses data assimilation from geosynchronous, GPS, and other radiation measuring platforms to provide a highly accurate nowcast of the penetrating electron environment. DREAM includes codes that implement spacecraft tracking using the space catalog to calculate the specific internal charging and dose rate conditions at a specific satellite of interest. Targeted applications include alerts/warnings, anomaly resolution for more reliable operations, and attack/anomaly assessment for space situational awareness. The DREAM system is written to be fully compliant with Service Oriented Architecture standards and even has an iDREAM Space Weather app for the publicly-available space weather services.