## 2 Radiation in Space and Its Effects on Electronic Components
### Methods for Assessing Radiation Exposure in Space Missions  
NASA AE8 (Electron Fluxes) and AP8 (Proton Fluxes) radiation models, which were developed in the 1960s using data from 43 satellites, are still widely used in the space industry despite being several decades old (their last revision dates back to the 1980s). Indeed, some researchers have pointed out serious problems with these models, such as errors in coordinate calculations, discrepancies in dose estimates between different NASA models, absurd results in some cases, errors in source code [18], lack of directional models, and over-prediction of electron flux [19]. To address the need for an improved model with better time resolution, three empirical models were developed based on data from the CRRES mission [20]. These models are CRRES-PRO, CRRES-ELE, and CRRES-RAD [21]. However, the major limitation of these models was that they were based on data collected during solar maxima and only covered14 months. To extend the CRRES-RAD model further, the APEX mission was launched, which gave birth to the APEXRAD model [22]. Also, several alternative models have been developed for modeling geostationary electron flux, such as POLE V1 and POLE V2. Radiation experts utilize a variety of tools, including computational models, particle accelerator experiments, on-orbit radiation monitoring systems, and software and databases, to accurately estimate the expected radiation levels. These tools, which we summarize below, provide essential information for the safe and successful operation of spacecraft systems. 1. Computational Models, such as the Space Environment Information System (SPENVIS--[[https://www.spenvis.oma.be/](https://www.spenvis.oma.be/)]([https://www.spenvis.oma.be/](https://www.spenvis.oma.be/)), accessed on 1 July 2023) and the NASA Space Radiation Analysis Group (SRAG--[[https://srag.jsc.nasa.gov/](https://srag.jsc.nasa.gov/)]([https://srag.jsc.nasa.gov/](https://srag.jsc.nasa.gov/)), accessed on 1 July 2023) models, use algorithms and simulations to estimate the radiation levels in an LEO based on the current and predicted space weather conditions. 2. Particle Accelerator Experiments and \({}^{60}Co\) radiation sources, such as the total ionizing dose test facilities [9], are conducted in laboratory settings to simulate the effects of radiation on electronic components and other materials. These experiments provide valuable data that can be used to improve computational models and the design of radiation-hardened components. 3. On-Orbit Radiation Monitoring Systems have been installed on the International Space Station (ISS) and the MIR Space Station, as well as on other satellites including NOAA's Polar Orbiting Environmental Satellites (Space Environment Monitor) and CubeSats, to measure radiation levels in space. The data collected by these systems can be used to validate computational models and improve our understanding of the space environment in an LEO. 4. Software and Databases: Radiation experts use various software tools and databases, such as AE8-AP8, SPENVIS, STK, etc., to analyze and interpret the data collected by on-orbit radiation monitoring systems and particle accelerator experiments. This study compares the dosimetry data of various LEO missions to gain a better understanding of the radiation environment in this space region. The comparison provides useful information for improving the accuracy of radiation prediction models and for the design of future radiation-hardened spacecraft. System Design for Space Missions: Applying RDM (Radiation Design Margin) to Overcome the Challenges of Space Radiation  
The design of electronic and electrical systems for space missions is governed by various standards and guidelines to ensure safety, reliability, and interoperability. In Europe, the European Cooperation for Space Standardization (ECSS) provides a framework for space program management (M series), quality (Q series), engineering (E series), and sustainability (U series).