MODELING THE VARIATIONS OF DOSE RATE MEASURED BY RAD DURING THE FIRST MSL MARTIAN YEAR: 2012–2014

Journal Article · Tue Sep 01 00:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/810/1/24· OSTI ID:22525513

Guo, Jingnan; Wimmer-Schweingruber, Robert F.; Heber, Bernd; Köhler, Jan; Appel, Jan K.; Böhm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Lohf, Henning; Martin, Cesar ^[1]; Zeitlin, Cary ^[2]; Rafkin, Scot; Hassler, Donald M.; Ehresmann, Bent ^[3]; Posner, Arik ^[4]; Brinza, David E. ^[5]; Kahanpää, H. ^[6]; Reitz, Günther ^[7]

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1. Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel (Germany)
2. Southwest Research Institute, Earth, Oceans and Space Department, Durham, NH (United States)
3. Southwest Research Institute, Space Science and Engineering Division, Boulder, CO (United States)
4. NASA Headquarters, Science Mission Directorate, Washington, DC (United States)
5. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States)
6. Finnish Meteorological Institute, Helsinki (Finland)
7. Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt, Köln (Germany)

The Radiation Assessment Detector (RAD), on board Mars Science Laboratory’s (MSL) rover Curiosity, measures the energy spectra of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic-ray (GCR) induced surface radiation dose concurrently: (a) short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, (b) long-term seasonal pressure changes in the Martian atmosphere, and (c) the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activity and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analyzed and fitted to empirical models that quantitatively demonstrate how the long-term influences ((b) and (c)) are related to the measured dose rates. Correspondingly, we can estimate dose rate and dose equivalents under different solar modulations and different atmospheric conditions, thus allowing empirical predictions of the Martian surface radiation environment.

• OSTI ID: 22525513
• Journal Information: Astrophysical Journal, Vol. 810, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ATMOSPHERIC PRESSURE
COMPUTERIZED SIMULATION
COSMIC RADIATION
DAILY VARIATIONS
DOSE RATES
ENERGY SPECTRA
MAGNETIC FIELDS
MARS PLANET
MODULATION
NEUTRAL PARTICLES
PLANETARY ATMOSPHERES
RADIATION DOSES
ROTATION
SOLAR ACTIVITY
SPACE VEHICLES
SUN
SURFACES