Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements

• DOI: 10.1007/s00159-021-00136-5
• Publication Date: 2021-09-21T09:02:59Z
• Authors: Jingnan Guo; Cary Zeitlin; Robert F. Wimmer-...; Donald M. Hassler; Bent Ehresmann; Scot Rafkin; Johan L. Freiherr...; Salman Khaksarighiri; Weihao Liu; Yuming Wang
• Keywords: 13. Climate action; 0103 physical sciences; 01 natural sciences; 7. Clean energy

Abstract Potential deleterious health effects to astronauts induced by space radiation is one of the most important long-term risks for human missions, especially future planetary missions Mars which require a return-trip duration about 3 years with current propulsion technology. In preparation exploration, Radiation Assessment Detector (RAD) was designed detect and analyze biologically hazardous energetic particle on Martian surface as part Science Laboratory (MSL) mission. RAD has measured deep field within spacecraft during cruise cosmic ray since Curiosity’s landing in August 2012. These first-ever data have been continuously providing unique direct assessment environment Mars. We temporal variation Galactic Cosmic Ray (GCR) observed Solar Energetic Particle (SEP) events from launch MSL until December 2020, i.e., pre-maximum solar cycle 24 throughout its minimum initial year Cycle 25. Over long term, Mars’s GCR increased 50% due declining activity weakening heliospheric magnetic field. At different time scales shorter also detected dynamic variations present quantify changes are mainly caused by: (a) influences include both temporary impacts transients evolution, (b) atmospheric daily thermal tide seasonal CO $$_2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msub> </mml:math> well altitude change rover, (c) topographical along rover path-way causing addition structural shielding finally (d) occur sporadically may significantly enhance short period. Quantification allows estimation accumulated return trip under various conditions. The dose equivalent, via Hohmann transfer, $$0.65 \pm 0.24$$ <mml:mrow> <mml:mn>0.65</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.24</mml:mn> </mml:mrow> sievert $$1.59 0.12$$ <mml:mn>1.59</mml:mn> <mml:mn>0.12</mml:mn> maximum periods, respectively. fields periods rather efficient reducing total GCR-induced mission, more than 50%. However, further contributions SEPs must be taken into account. future, advanced nuclear thrusters fast we estimate that equivalent can reduced 0.2 0.5 addition, examined factors reduce discuss many uncertainties interpreting biological effect based measurement.