1. Title page Life on Mars? Modeling the subsurface radiation environment Lewis Dartnell CoMPLEX University College London Andrew Coates, MSSL John Ward, Biochemistry Laurent Desorgher, Bern

2. Summary Astrobiology & Mars Radiation environment My research & computer model

3. Mars today 6 mbar atmosphere, freezing surface temperatures, bone- dry surface sterilised by UV and cosmic radiation

4. Refugial Life Could extremophile life persist beneath the surface, within pockets of liquid water…? Deep hot Biosphere on Earth. Methane plumes detected seeping out of ground.

5. Space radiation

6. Secondary cascades CGR primary produces extensive shower of secondary particles, with a core of hadrons (nuclear fragments, protons, neutrons) and pions within a spreading cone of the electromagnetic cascade (gamma and electrons) mediated by muon decay. Pfotzer maximum in Earth’s atmosphere at an altitude of ~60,000ft Flux diminished to ~1% at sea-level

7. Biological effects Direct & Indirect, [O 2 ] & Temp. dependence E. coli B. subtilis D. radiodurans

8. The Model

9. Sites of interest

10. Results I

11. Results II

12. Results III

13. Results IV

14. Final Goal Which sites should we send our landers to? How deep would they need to drill? Coming up… Persistence time of biomarkers Optically-Stimulated Luminescence (OSL) dating Lab work

15. … questions ?