The Radiation Assessment Detector (RAD) Investigation

Hassler, Donald M.; Zeitlin, C.; Wimmer‐Schweingruber, R. F.; Böttcher, S.; Martı́n, César; Andrews, John P.; Böhm, E.; Brinza, D. E.; Bullock, M. A.; Burmeister, Soenke; Ehresmann, Bent; Epperly, M.; Grinspoon, David; Köhler, Jan; Kortmann, Onno; Neal, K.; Peterson, Joseph; Posner, A.; Rafkin, S. C.; Smith, K. D.; Tyler, Y.; Weigle, Gerald; Reitz, Günther; Cucinotta, Francis A.

doi:10.1007/978-1-4614-6339-9_15

Cited by 27 publications

(44 citation statements)

References 71 publications

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“…To investigate the extent by which the upstream space weather activity impacted the Martian ionosphere down to the surface, observations from MAVEN, MEX, Mars Odyssey, and/or MSL can be used together. For example, MAVEN observations for event periods in which SEPs and/or CMEs impacted Mars can be compared with the surface measurements of the radiation dose rates by the MSL Radiation Assessment Detector (RAD) [Hassler et al, 2012] to examine and characterize the observations for Forbush decreases and dose rate enhancements [Hassler et al, 2014] ( Lee et al, manuscript in preparation).…”

Section: Discussionmentioning

confidence: 99%

MAVEN observations of the solar cycle 24 space weather conditions at Mars

et al. 2017

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The Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has been continuously observing the variability of solar soft X‐rays and EUV irradiance, monitoring the upstream solar wind and interplanetary magnetic field conditions and measuring the fluxes of solar energetic ions and electrons since its arrival to Mars. In this paper, we provide a comprehensive overview of the space weather events observed during the first ∼1.9 years of the science mission, which includes the description of the solar and heliospheric sources of the space weather activity. To illustrate the variety of upstream conditions observed, we characterize a subset of the event periods by describing the Sun‐to‐Mars details using observations from the MAVEN solar Extreme Ultraviolet Monitor, solar energetic particle (SEP) instrument, Solar Wind Ion Analyzer, and Magnetometer together with solar observations using near‐Earth assets and numerical solar wind simulation results from the Wang‐Sheeley‐Arge‐Enlil model for some global context of the event periods. The subset of events includes an extensive period of intense SEP electron particle fluxes triggered by a series of solar flares and coronal mass ejection (CME) activity in December 2014, the impact by a succession of interplanetary CMEs and their associated SEPs in March 2015, and the passage of a strong corotating interaction region (CIR) and arrival of the CIR shock‐accelerated energetic particles in June 2015. However, in the context of the weaker heliospheric conditions observed throughout solar cycle 24, these events were moderate in comparison to the stronger storms observed previously at Mars.

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Section: Discussionmentioning

confidence: 99%

MAVEN observations of the solar cycle 24 space weather conditions at Mars

et al. 2017

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“…To evaluate the radiation risks for future human exploration of Mars, the Radiation Assessment Detector (RAD, Hassler et al, ) was designed to detect and analyze the most biologically hazardous energetic particle radiation during the cruise to Mars and on the Martian surface as part of the Mars Science Laboratory (MSL, Grotzinger et al, ). Since August 2012, MSL/RAD has provided the first assessment of the radiation environment on the Martian surface (Hassler et al, ) which is fundamental for evaluating the radiation risks and the consequent biologic effects likely to be encountered during a typical Mars mission.…”

Section: Introductionmentioning

confidence: 99%

Subsurface Radiation Environment of Mars and Its Implication for Shielding Protection of Future Habitats

et al. 2020

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In order to quantify the optimal radiation shielding depth on Mars in preparation for future human habitats on the red planet, it is important to understand the Martian radiation environment and its dependence on the planetary atmospheric and geological properties. With this motivation we calculate the absorbed dose and equivalent dose rates induced by galactic cosmic ray particles at varying heights above and below the Martian surface considering various subsurface compositions (ranging from dry rock to water‐rich regolith). The state‐of‐the‐art Atmospheric Radiation Interaction Simulator based on GEometry And Tracking Monte Carlo method has been employed for simulating particle interaction with the Martian atmosphere as well as subsurface materials. We calculate the absorbed dose in two different phantoms: a thin silicon slab and a water sphere. The former is used to validate our model against the surface measurement by the Radiation Assessment Detector on the Curiosity rover, while the later is used to approximate a human torso, also for evaluation of the biologically weighted equivalent dose. We find that the amount of hydrogen contained in the water‐rich regolith plays an important role in reducing the equivalent dose through modulation of neutron flux (below 10 MeV). This effective shielding by underground water is also present above the surface, providing an indirect shielding for potential human explorations at this region. For long‐term habitats seeking the Martian natural surface material as protection, we also estimate the optimal shielding depth, for different given subsurface compositions, under maximum, average, and minimum heliospheric modulation conditions.

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“…To support the RAD measurements [ Hassler et al , ; Zeitlin et al , ], it is necessary to perform numerical simulations of the cosmic ray transport to the surface of Mars. The solar activity and the Martian atmospheric profile, both highly variable, are responsible for the radiation fluctuations at ground level, and the simulations need to explore the whole parameter space.…”

Section: Introductionmentioning

confidence: 99%

Influence of dust loading on atmospheric ionizing radiation on Mars

2014

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Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

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The Radiation Assessment Detector (RAD) Investigation

Cited by 27 publications

References 71 publications

MAVEN observations of the solar cycle 24 space weather conditions at Mars

MAVEN observations of the solar cycle 24 space weather conditions at Mars

Subsurface Radiation Environment of Mars and Its Implication for Shielding Protection of Future Habitats

Influence of dust loading on atmospheric ionizing radiation on Mars

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