Mars and the Mystery of the Missing Organics
We have previously demonstrated that the PanCam filter system combined with a single Nichia 365 nm LED can detect as little as 1.5 ug of pyrene at a distance of 1 meter in 65 seconds. Preliminary studies with 375 nm laser diodes indicate it would possible to equip any rover or lander RGB camera system with a photonic probe capable of rapidly interrogating drill cuttings at 2-20 meters. A L.I.F.E. system such as this could also scan inaccessible regions such as the cracks and crevices of rugged outcrops. As an additional capability, these UV excitation wavelengths would produce fluorescence in exobiological analogues to ubiquitous metabolic compounds like nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD); photosynthetic pigments such as bacteriochlorophyll and the quinones; and diagenetic products of microbial life. FAD and NADH fluorescence changes with oxidation state making possible in situ remote sensing of metabolic activity.
References
Storrie-Lombardi, M.C., Muller, J.-P., Fisk, M.R., Cousins, C., Sattler, B., Griffiths, A.D. and Coates,
A.J. (2009) Laser induced fluorescence emission (L.I.F.E.): searching for Mars organics with a UV
Enhanced PanCam. Astrobiology 9(10): 953-964.
Storrie-Lombardi, M. C., J.-P. Muller, M. R. Fisk, A. D. Griffiths, and A. J. Coates (2008), Potential for non-destructive astrochemistry using the ExoMars PanCam, Geophys. Res. Lett., 35, L12201, doi 10.1029/2008GL034296.
Storrie-Lombardi, M. C., Hug, W. F., McDonald, G. D., Tsapin, A. I. and Nealson, K. H. (2001) Hollow cathode ion lasers for deep ultraviolet Raman spectroscopy and fluorescence imaging. Rev. Sci. Ins. 72:(12), 4452-9. Abs_UV_Raman_2001.pdf
Fisk, M. R., Storrie-Lombardi, M.C., Douglas, S., McDonald, G.D. (2003) Popa, R. Evidence of biological activity in Hawaiian subsurface basalts. Geochemistry, Geophysics, and Geosystems 4, 1-24, 2003. Abs_DeepLife_2003.pdf
Dorn, E. D., McDonald, G. D., Storrie-Lombardi, M. C., and Nealson, K. H. Principal component analysis and neural networks for detection of amino acid biosignatures Icarus 166 (2): 403-409. Abs_PCA_ANNs_AmAc_2003.pdf
Nealson, K.H., Tsapin, A., and Storrie-Lombardi, M. (2002) Searching for life in the Universe: unconventional methods for an unconventional problem. Int. Microbiol. 5:223-230.
Fisk, M. R., R. Popa, O. U. Mason, M. C. Storrie-Lombardi and Vicenzi, (2006) E. P. Iron-magnesium silicate bioweathering on Earth (and on Mars?). Astrobiology 6, 48-68. Abs_Nakhla_2006.pdf
Storrie-Lombardi and Fisk, M. R. (2004) Elemental abundance distributions in sub-oceanic basalt glass: evidence of biogenic alteration. Geochem. Geophys. Geosys., 5 (10), 1-15, Q10005, doi:10.1029/2004GC000755. Abs_Elements_2004.pdf
McDonald, G. D. and Storrie-Lombardi, M. C. (2006) Amino acid distribution in meteorites: diagenesis, contamination, and standard metrics in the search for extraterrestrial biosignatures. Astrobiology 6, 17-33. Abs_Meteorites_ANN_2006.pdf
Storrie-Lombardi, M. C., Lahav, O., Sodre, L., and Storrie-Lombardi, L. J. (1992) Morphological classification of galaxies by artificial neural networks Mon. Not. Roy. Astro. Soc. 259, 8-12. Abs_Galaxies_NeuralNetworks.pdf
Viking Lander 2 at Utopia Planitia in 1977. Scanning Camera
image of water ice frost and panoramic view .
Lat/Lon (deg) 47.57N, 225.74W Images: NASA/Viking Team
Pathfinder at Ares Vallis (1998).
Sojourner interrogating Moe with APXS and panoramic view .
Lat/Lon (deg) 19.33N, 33.55W Images: NASA/Pathfinder Team
Artistic Rendition of ExoMars rover [Credit:
ESA/ExoMars Team]modified to depict possible placement of 2 UV lasers for PAH detection using the Wide Angle Cameras.
Broad infrared spectral emission features characteristic of PAHs are found in the interstellar medium (ISM) of nearby star forming regions, protoplanetary disks, our Milky Way galaxy , neighboring galaxies, and Titan’s atmosphere. In Solar system meteorites, including carbonaceous chondrites and Mars meteorites, the most common PAH species are 2-, 3-, and 4-ring structures such as naphthalene, phenanthrene, anthracene, pyrene, and chrysene. Comets, meteorites, micrometeorites, and ISM dust daily deliver large quantities of PAHs to the surface of Mars. However, the Viking mission failed to detect organic compounds in the upper few centimeters of the regolith at ppb levels. Current theories postulate destruction of in-fall material by direct or indirect damage from ionizing radiation. However, simulations predict attenuation of damage as a function of depth and survival of organics ~1-2 meters below the Mars surface.
The European Space Agency (ESA) is developing the ExoMars rover mission to search for evidence of past or present biological activity in the near subsurface of the Mars regolith. Unfortunately, the presently planned organic detection intruments require either sample destruction and/or consumption of limited chemical resources. Fortunately, ExoMars instrumentation includes a mast-mounted PanCam with a wide variety of filter bands collecting visible to near infrared images. In exploration of extreme environments on Earth it is useful to do preliminary triage using optical probes requiring only renewable energy (Storrie-Lombardi, 2005). We have previously proposed native fluorescence as a Mars in situ survey tool since it is the most sensitive active imaging probe for detecting aromatic organics that does not require sample preparation, expenditure of limited reagents, or target destruction (Storrie-Lombardi et al., 2001; Nealson et al., 2002). Near UV (350-380 nm) excitation of small aromatic organic molecules including 3-, 4-, and 5-ring PAHs produces fluorescence in the visible spectrum making PanCam fluorescence imaging feasible.
Mars Exploration Rover Spirit at Columbia Hills (2004). PanCam images of layered rock at Columbia Hills and panoramic view of Gusev crater landing site. Images: NASA/Cornell/MER Team
Beagle PanCam Tests, Death Valley, Califronia (2008).
Visible Image
Fluorescence Image
Drill simulation with PAH-doped peridotite fluorescence excited by 365 nm Nichia LED. Images: Kinohi Institute
