A study of SPEs ​and the consequences of radiation exposure

Abstract: With thorough literature studies as well as simulations, a way to minimize the exposure to radiationthat astronauts are at risk of encountering during a solar proton event is sought. The understanding ofwhere these particles come from, as well as the random nature of solar particle events is of importancein order to predict their occurrence. Different models used for predicting solar particle events based on aPoisson possibility distribution are presented, as well as real-time forecasts which give a warning of anapproaching event. Although the models used for real-time forecasts have a high accuracy rate, the averagewarning time is only approximately one hour. The downside with the predicted possible occurrence isthat this only gives a statistical probability of events that could possibly occur. For the real-time forecaststhe downside is that with an average warning time of only one hour, they do not give a lot of time forseeking shelter during the onset of an event. With simulations it is shown that the best way to minimizethe radiation dose obtained by astronauts is to use different materials of shielding. It is also shown that alower shielding thickness when encountering SPEs, for example when in a space suit, is useful as longas the total amount of time spent in this suit during the duration of a mission is planned thoroughly inorder to stay below the radiation dose limits. If an astronaut would be caught in an event with the samemagnitude and intensity as the solar particle event of August 1972, it is shown that the astronaut onlyhas nine minutes to seek shelter before exceeding the radiation dose limits and thereby risking radiationinduced sickness.