Measurements of Space Radiation On, and On the Way To, Mars - Paper 123

Conference · Mon Sep 15 04:00:00 EDT 2014

OSTI ID:23082942

Zeitlin, Cary ^[1]

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1. MSL-RAD Science Team, Southwest Research Institute, Earth, Oceans and Space, Durham, NH (United States)

The Mars Science Laboratory (MSL) spacecraft, with the Curiosity rover inside, was launched to Mars on November 25, 2011, and landed successfully on August 6, 2012. Curiosity's science payload includes ten science instruments, one of which is the Radiation Assessment Detector, RAD. The radiation environment in deep space is harsh, and is a limiting factor in planning future human missions. RAD's measurements of the radiation environments on Mars, and on a spacecraft during transit to Mars, are important precursors to a crewed mission. RAD is a compact instrument with a mass of just 1.56 kg. Despite its small size, RAD is capable of measuring the charged and neutral particles that make up the complex environments created by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) as they traverse shielding materials. The space radiation environment consists of a continuous flux of GCRs, the intensity of which is modulated by solar activity. At or near times of solar maximum, the interplanetary magnetic field is relatively strong, and lower-energy GCRs are screened. At solar minimum, the field weakens with a corresponding increase in GCR fluxes. SEP events are sporadic, and are more likely to occur near solar maximum. Both GCRs and SEPs present potential health risks to astronauts, but the risks are of different types. The dose rate from GCRs is modest and cannot cause acute health effects. However serious late effects may arise; of particular concern are the largely unknown health effects of exposure to high-energy GCR heavy ions. There is no terrestrial analog for this exposure and this leads to large uncertainties in health risk estimates. In contrast, SEP events can be extremely intense and could potentially cause acute health effects, but they are also dominated by protons with energies below 100 MeV, which means that shielding is a practical and effective option. (authors)

• Research Organization: American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 23082942
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
ASTRONAUTS
COSMIC RADIATION
DOSE RATES
HEALTH HAZARDS
HEAVY IONS
INTERPLANETARY MAGNETIC FIELDS
MARS PLANET
MEV RANGE 10-100
NEUTRAL PARTICLES
SHIELDING
SHIELDING MATERIALS
SOLAR ACTIVITY
SPACE VEHICLES