Modeling the Radiation Environment of a Mission to Mars
Résumé
Detecting life in the Solar System is one of the great challenges of new upcoming space missions. It implies to send new sophisticated devices to bodies of interest (like Mars) to try to perform in-situ measurements which will give hints of the presence, or lack, of organic matter. One of those devices could be a biological sensitive system called biochip that our team is developing. The main concern is to ensure the survival of such a device during a full space mission. Space radiation appears clearly as a critical parameter requiring a detailed investigation. In this abstract, we present our simulation work to define the radiation environment a biochip would face during a typical mission to Mars. First results were obtained with two computing tools based on the Geant4 Monte Carlo toolkit : GRAS and Planetocosmics. Calculations on Earth-Mars travel have been performed with the GRAS tool: we focused on ionizing dose and fluences inside a rudimentary aluminum rover. For the Mars journey, we adopted a two-step simulation strategy. The first step consisted in simulating, with Planetocosmics, the interaction of GCR (Galactic Cosmic Rays) and SEP (Solar Energetic Particles) spectra with Mars atmosphere and soil in order to quantify the radiation environment at soil level. In a second step, we studied the impact of these particle fluxes on a biochip placed inside a rover exploring the Mars surface for a period of one month. As simulations revealed a large abundance of neutrons backscattered by the Mars soil, we've obtained beam time at the French AIFIRA facility in order to irradiate biochip constituents with neutrons very soon.