This article describes the nowcast of aerospace radiation system (NAIRAS) model, which is now publicly available at the Community Coordinated Modeling Center (CCMC). NAIRAS predicts dosimetric and radiation flux quantities for assessing human radiation exposure and radiation effects to flight vehicle electronic systems from the surface of the Earth to deep space. 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 presented for aircraft and various spaceflight platforms.