Radiation Environments on Mars and Their Implications for Terrestrial Planetary Habitability

摘要

The understanding of the surface and subsurface radiation en-vironments of a terrestrial planet such as Mars is crucial to its potential past and/or present habitability. Despite this, the subject of high energy radiation is rarely contemplated within the field of Astrobiology as an essential factor de-termining the realistic parameter space for the development and preservation of life.Furthermore, not much is known of the radiation environment on the sur-face of Mars due to the fact that no real data exist on this contribution. There are no direct measurements available as no surface landers/probes have ever carried nuclear radiation detection equipment to characterize the interactions arising from cosmic ray bombardment, solar particle events and the atmosphere striking the planetary surface. The first mission set to accomplish this task, the Mars Science Laboratory, is not scheduled to launch until 2011.Presented here are some of such simulations performed with the HZETRN NASA code offering radiation depth profiles as well as a characterization of the diverse radiation environments. A discussion of the implications that these pro-jected doses would have on terrestrial planetary habitability on Mars is presented as well as its implications for the habitability of terrestrial planets elsewhere. This work does not provide an estimate of the UV radiation fields on the Mar-tian surface instead it focuses on the high energy radiation fields as composed by galactic cosmic rays (GCRs).