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Janessa Buhler

Publications and source records attributed to Janessa Buhler.

Commercial Crew Program (CCP) Post-flight Reference Radiation Environments

The Nowcast of Aerospace Ionizing RAdiation System (NAIRAS) model version 3 is a coupled physics-based model that transports ionizing radiation through the heliosphere, Earth’s magnetosphere, the neutral atmosphere, and aircraft and spacecraft shielding. Ionizing radiation sources included in the model are: 1) galactic cosmic rays, 2) solar energetic particles including protons and heavy ions, and 3) the inner radiation belt trapped protons and electrons. NAIRAS predicts dosimetric quantities and differential and integral flux and fluence quantities for assessing human radiation exposure and single event effects in vehicle electronic systems from the Earth’s surface to the space environment.

Christopher J Mertens

NAIRAS Ionizing Radiation Model: Extension from Atmosphere to Space

The Nowcast of Aerospace Ionizing RAdiation System (NAIRAS) model is a real-time, global, physics-based model originally developed to predict exposure from cosmic radiation to air travelers from both galactic and solar sources. A prototype operational NAIRAS model has provided tabular and graphical data products via its public web site for about ten years. A new version of the NAIRAS model has been developed that incorporates an extension of the model domain from the atmospheric ionizing radiation environment to the space radiation environment, with the addition of the trapped inner belt proton source and altitude-dependent and rigidity-dependent geomagnetic shielding of the galactic cosmic rays (GCR) and solar energetic particle (SEP) protons. New output products of differential and integral particle flux have been developed for the characterization of single-event effects (SEE), expanding the application of NAIRAS from human radiation exposure assessment to allowing end-users to quantify radiation environment risks to aviation and spacecraft microelectronic systems. The NAIRAS model has transitioned to prototype operations at the Community Coordinated Modeling Center (CCMC) where the model now operates in two modes: (1) real-time global predictions of the atmospheric radiation environment and (2) a run-on-request (RoR) service allowing the user to select a specific time period for the global dosimetric calculations, or to upload an aircraft, balloon, or spaceflight trajectory file to provide predictions of the dosimetric and particle flux quantities along the flight path. The new features of NAIRAS version 3.0 are described in this paper and example results of the new output products for low-Earth orbit (LEO), medium-Earth orbit (MEO), and free-space radiation environments are presented

Christopher J. Mertens

NAIRAS Model transition to the CCMC: real-time dosimetric output and low-Earth orbit applications

NASA’s Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is areal-time, global, physics-based model originally developed to predict exposure to cosmic radiation to air travelers from both galactic and solar sources. A prototype operational NAIRAS model has provided tabular and graphical data products via its public web site for a number of years. We present the advances in the transition of NAIRAS to operations at the Community Coordinated Modeling Center (CCMC), located at NASA Goddard Space Flight Center, where global NAIRAS products are available for a real-time space weather version of the model. In addition, a runs-on-request version provides model output along user selected flight trajectories. We show the global dosimetric output from the model that are available in real-time as well as the new products developed to support commercial spaceflight missions to low-Earth orbit(LEO) and the International Space Station (ISS).

Guillaume Gronof

NAIRAS Model Updates and Improvements to the Prediction of the Ionizing Radiation Environment from the Earth's Surface to Geospace

- NAIRAS Model Description - Nowcast of Aerospace Ionizing RAdiation System (NAIRAS) Model - Running in real-time on LaRC computer cluster since 2011, results hosted on Space Environment Technologies server/website - Running in real-time at CCMC since 2020 - Key Model Features - Global ionizing radiation environment model - Physics-based HZETRN (High Charge (Z) and Energy TRaNsport) code - Real-time inclusion of solar energetic particle (SEP) radiation - Real-time solar-magnetospheric effects on radiation (cutoff model by Kress et al. [2004, 2010]) - New/Current Model Development - Improved SEP dose nowcast and forecast - Extend to low-Earth orbit (LEO) environment - Single-Event Effects (SEE) radiation risk assessment quantities - Run-on-Request (RoR) @ CCMC

Christopher J. Mertens