Title page

Life on Mars?Modeling the subsurface radiation environment

Lewis DartnellCoMPLEX

University College London

Andrew Coates, MSSL John Ward, Biochemistry Laurent Desorgher, Bern

SummaryAstrobiology & Mars

Radiation environment

My research & computer model

Mars today• 6 mbar atmosphere, freezing surface temperatures, bone-

dry surface sterilised by UV and cosmic radiation

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.

Space radiation

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

Biological effectsDirect & Indirect, [O2] & Temp. dependence

E. coli

B. subtilis

D. radiodurans

The Model

Sites of interest

Results I

Results II

Results III

Results IV

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

… questions ?