HR: 16:30h
AN: SH54A-03 INVITED     [Abstracts]
TI: Radiation and the Exploration of the Moon and Mars: Current Knowledge, Challenges, and Required Measurements
AU: * Delory, G T
EM: gdelory@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Zeitlin, C
EM: cjzeitlin@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 74-0103B, Berkeley, CA 94720 United States
AU: Luhmann, J G
EM: jgluhman@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Gorguinpour, C
EM: camron@ssoar.org
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Brain, D A
EM: brain@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Lee, C O
EM: clee@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Mitchell, D
EM: mitchell@apollo.ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AB: The NASA Exploration Initiative calls for a long term human presence on the Moon and eventually Mars, and radiation is among one of many environmental factors that may affect both system and human safety in this endeavor. The importance of radiation in spacecraft operations was recently underscored by a host of anomalies and failures occurring throughout the solar system during the Halloween storms in 2003. A combination of measurements, modeling, and predictive capabilities should provide a framework to mitigate this threat for a variety of future space and planetary missions. Here we consider the energetic, highly penetrating ionizing radiation found in Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) in the context of the exploration of the Moon and Mars. The high-Z and energy GCR spectra have been fairly well characterized, while the occurrence of SEPs is still an active area of current research. SEP composition is primarily protons and usually limited to $<$ GeV energies, yet their intensity and variability make these events an important consideration when compared to the relatively low-flux but constant GCR background. SEP events may be especially relevant for operations on the lunar surface, while only exceptionally intense and energetic SEPs may impact the surface of Mars due to the presence of an atmosphere. For both GCR and SEP radiation fields, a major uncertainty for exposure on the surface or in transit is the interaction of these particles with the atmosphere, shielding materials and subsurface regolith, since secondaries can represent a large contribution to the absorbed dose in a given location. We will discuss the current state of knowledge regarding the radiation environment on the Moon and Mars, some specific examples of system failures, and the need for experimental validation of radiation transport models through strategically chosen measurements on future human precursor missions.
DE: 7513 Coronal mass ejections
DE: 7514 Energetic particles (2114)
DE: 7594 Instruments and techniques
DE: 7807 Charged particle motion and acceleration
DE: 7894 Instruments and techniques
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting