What Is the Radiation Impact of Extreme Solar Energetic Particle Events on Mars?

Abstract

Solar Energetic Particles (SEP) are one of the major sources of the Martian radiation environment. It is important to understand the SEP‐induced Martian radiation environment for future human habitats on Mars. Due to the lack of a global intrinsic magnetic field, Solar Energetic Particles (SEPs) can directly propagate through and interact with its atmosphere before reaching the surface and subsurface of Mars. Mars has many high mountains and low‐altitude craters where the atmospheric thickness can be more than 10 times different than one another. The SEP‐induced surface radiation level may therefore be very different from one location to another. We thus consider the influence of the atmospheric depths on the Martian radiation levels including the absorbed dose, dose equivalent, and (human‐)body effective dose induced by SEPs at varying heights above and below the Martian surface. The state‐of‐the‐art Atmospheric Radiation Interaction Simulator based on GEometry And Tracking Monte‐Carlo method has been employed for simulating particle interactions with the Martian atmosphere and terrain. We find that even the thinnest Martian atmosphere reduces radiation dose from that in deep space by at least 65%, and the shielding effect increases for denser atmosphere. Furthermore, we present a method to quickly forecast the SEP‐induced radiation in different regions of Mars with different surface pressures.

Conceptual Architectural Response to Radiation on Mars

“…GCR is of galactic and extra-galactic origin, like supernova remnants [10], and remains relatively stable, except for supernova flares. The energy spectrum of galactic protons may reach 10 21 GeV (gigaelectron volt) with very rare particles of high energy (the energy of particles lower than ~10 6 GeV is considered to be low energy); at an energy ~10 GeV their flux is 1 particle/m 2 s, in PeV (petaelectron volt)-area ~1 particle/m 2 year [11]. SCR originates from the Sun, mostly from coronal ejections.…”

“…On the other hand, Rojdev and Atwell [24] claim that nanoporous carbon composites (CNTs) outperform aluminium as a shielding material, remaining material with good structural properties at the same time. Also, Naito et al [25] theoretically proved much higher anti-radiation shielding efficiency of 6 Li 10 BH 4 (enriched lithium borohydride), 6 LiH (lithium-6 hydride), NH 3 BH 3 (ammonia borane, a ring structure of boron and nitrogen bound via conjugated double bonds), carbon fibre reinforced plastic and SiC composite plastic, compared to aluminium. However, efficiency will only really be proved in the real conditions of cosmic travel and Mars inhabitance.…”

“…875 Pa at Gale Crater [5]. The thin atmosphere of Mars can even significantly increase the problem of radiation due to the production of secondary particles, mainly neutrons [6]. It should be mentioned that some of the solutions used for the protection of humans on spacecraft could potentially be adapted and subsequently applied in the architecture of the settlements on the planet.…”