2016-07-282016-07-282016-07-10ICES_2016_59http://hdl.handle.net/2346/67500United StatesUniversity of Tennessee503ICES503: Radiation Issues for Space FlightVienna, AustriaNatalie A. McGirl, University of Tennessee, USAA.J. Pawel, University of Tennessee, USADaniel P. Schappel, University of Tennessee, USAJacob Shamblin, University of Tennessee, USATimothy R. Younkin, University of Tennessee, USALawrence W. Townsend, University of Tennessee, USAThe 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.Some recent analyses of potential radiation exposures to crews on the surface of Mars focused solely on exposures from extremely large solar particle events (SPE). These analyses estimated radiation doses to critical organs, as well as effective doses, and compared them to crew permissible exposure limits. Contributions to crew exposures from galactic cosmic rays (GCR) were not addressed. In this work we present results for crew exposure estimates from GCR particles, as well as SPE protons. We assume a 200-day transit between Earth and Mars, a 500-day stay on the surface of Mars, and a 200-day transit from Mars back to Earth. For the transit phases of the mission we assume that the crew is protected by a spacecraft having 20 g cm-2 aluminum or 40 g cm-2 aluminum shielding. For the stay on the surface of Mars, we assume a habitat shielded by 40 g cm-2 aluminum within the Martian atmosphere at altitudes of 0 km and -7 km – the former corresponding to the mean surface elevation, and the latter to the depth of the Hellas Impact Basin. The mission is assumed to begin 450 days prior to solar maximum and to end 450 days after solar maximum. The maximum for solar cycle 23 is used and assumed to have occurred on May 15, 2000. Radiation exposure estimates are obtained utilizing the Online Tool for the Assessment of Radiation in Space (OLTARIS) computational tool developed at NASA Langley Research Center. For the SPE contributions, the maximum SPE proton fluences that can be tolerated without exceeding career radiation limits are estimated, after accounting for the contribution to the total mission effective dose from the chronic GCR background exposures.application/pdfenggalactic cosmic raysolar particle eventdoseeffective dosePresentation