Advances in NAIRAS Atmospheric and Space Radiation Nowcast and Forecast

The Nowcast of Aerospace Ionizing RAdiation System (NAIRAS) model is composed of coupled physics-based models that transport ionizing radiation through the heliosphere, Earth’s magnetosphere, the neutral atmosphere, and aircraft and spacecraft shielding. The three sources of ionizing radiation included in the model are: (1) the ubiquitous galactic cosmic rays (GCR) with origins outside the solar system, (2) solar energetic particles (SEP), including heavy ions, arising from transient solar eruptive storm events, and (3) the inner radiation belt trapped protons (TRP). The transmission of GCR and SEP ions through the geomagnetic field includes the dynamical influence of the interplanetary plasma and magnetic field. The NAIRAS model predicts dosimetric quantities and differential and integral flux and fluence quantities for assessing human radiation exposure and single event effects (SEE) in vehicle electronic systems from the Earth’s surface to the space environment. The recent NAIRAS version 3.0 is running at the Community Coordinated Modelling Center (CCMC). Some recent improvements in NAIRAS nowcast capabilities include SEP heavy-ions during solar storm events and quasi real-time predictions of the radiation environment at the International Space Station (ISS). Preliminary results of SEP dose forecasts are shown by coupling the University of Malaga Solar Energetic Particle (UMASEP) model of integral proton flux forecasts with the NAIRAS model. NAIRAS predictions of the ionizing radiation environment are shown for various space weather conditions in the atmosphere and in low-Earth orbit (LEO), medium-Earth orbit (MEO), and cislunar orbit. NAIRAS model comparisons with dosimeter measurements are shown for commercial and high-flying aircraft, stratospheric balloons, and various spaceflight platforms.