Long term variations of galactic cosmic radiation on board the International Space Station, on the Moon and on the surface of Mars

Abstract

<div class="abstract"> <p> <div><div class="abstract"> <div><p>The radiation environment in free space and the related radiation exposure is seen as one of the main health detriments for future long-duration human exploration missions beyond Low Earth Orbit (LEO). The steady flux of energetic particles in the galactic cosmic radiation (GCR) produces  a low dose-rate radiation exposure, which is heavily influenced by several factors including the solar cycle, the presence of an atmosphere, relevant magnetic fields (as on Earth) and of course by the relevant spacecraft shielding. Investigations of the GCR variations over the course of a solar cycle provide valuable data for exploration mission planning and for the determination of the radiation load received due to the GCR environment. Within the current work these investigations have been performed applying three datasets generated on board the International Space Station (ISS) with the DOSTEL instruments in the frame of the DOSIS and DOSIS-3D projects, with the CRaTER instrument in a Moon orbit and with the MSL-RAD instrument on the way to and on the surface of Mars. To derive GCR dose contributions on board the ISS two procedures have been developed separating the contributions from GCR from passing’s through the South Atlantic Anomaly (SAA), as well as ways to extrapolate the GCR dose measured on board the ISS to free space based on various ranges of the McIlwain <em>L</em>-shell parameter. At the end we provide a dataset spanning the timeframe for GCR measurements on the ISS (2009 – 2011 & 2012 – 2019), Moon (2009 – 2019) and Mars (2012 – 2019), thereby covering the time span from the deep minimum of solar cycle 23, the ascending phase and maximum of solar cycle 24, and the descending phase of cycle 24, which is ongoing at the time of this writing.</p> </div> </div></div> </p> </div>

The Responses of the Black Fungus Cryomyces Antarcticus to High Doses of Accelerated Helium Ions Radiation within Martian Regolith Simulants and Their Relevance for Mars

“…In the present experiment, we only considered the effects of accelerated He ions, which make up 12% of GCR spectrum [42]. The fluxes of He ions on the Martian surface were measured by the Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover over two distinct periods [39,42]; the GCR fluxes on Martian surface depends on the thickness of the atmosphere and the modulation by heliosphere, both of which vary periodically [47,50,51], and are not composed exclusively of α particles (similar to He ions), they also includes gamma rays and a large proportion of protons, as well as some heavier nuclei. However, a simplified model may be proposed which gives an approximation of the time that would be required by each fungal cell to be hit by as many particles (He ions) as used in the present experiment.…”

Galactic Cosmic Ray Modulation at Mars and beyond measured with EDACs on Mars Express and Rosetta

“…With this instrument, Semkova et al (2018) observed changes in the GCR-related dose rate in accordance with the declining phase of the solar cycle. The GCR radiation dose has also been measured at the Martian surface by the MSL-RAD instrument, where the solar cycle modulation was observed (Berger et al 2020). The dose rate was found to be fairly similar to that on the Moon, although the presence of the Martian atmosphere shields the surface from lower-energy GCRs, resulting in a reduced modulation effect.…”

Iron Ion Particle Radiation Resistance of Dried Colonies of Cryomyces antarcticus Embedded in Martian Regolith Analogues

“…Through the LET value of the accelerated iron ions (200 keV/µm), it is possible to calculate the number of the particles that hit every sample at each exposure dose [36]. However, depending on the solar modulation and differences in atmospheric depth, CRs fluxes on the Martian surface can vary over time [37,38]. Therefore, an accurate estimation of the time frame required to absorb similar numbers of particles is not possible.…”