Analysis of the charged particle radiation effect for a CubeSat transiting from Earth to Mars

This paper presents a computational estimation of the total ionizing dose from protons and electrons in the Earthʹs magnetosphere and interplanetary space for a hypothetical CubeSat transiting from Earth to Mars. An initial hyperbolic escape of the spacecraft from Earthʹs gravitation is assumed, followed by an elliptical transfer from Earth to Mars under the Sunʹs gravitation. The rapid traversal of the Earthʹs radiation belt yields a smaller ionizing dose, whereas high-energy solar protons in the interplanetary space have the greatest effect on the ionizing dose during the transfer between the planets. Variation in the heliocentric distance of the spacecraft is considered in the calculation. Calculation of the shielding distributions with Geant4 and the transport of the ionizing particles across the obtained distributions yields an estimation of the total ionizing dose as a function of position within the spacecraft as well as statistical confidence levels. With a moderate confidence level, this calculation shows that a practical exploration of Mars with a CubeSat is possible in terms of the expected total ionizing dose.