- Количество слайдов: 19
Wide Angle Laser Imaging (W. A. L. I. ) for Mars Astrochemistry : Economic and Operational Advantages of a Pan. Cam triage system for organics & life detection Jan-Peter Mullard Space Science Laboratory, UCL, UK Michael C. Storrie-Lombardi Kinohi Institute, Pasadena, California USA http: //www. kinohi. org Evaluating fluorescence in regolith extruded by drill. Wide angle search mode.
Organic Deposition On Mars from Meteorites, Micrometeorites, and Dust • Even in the absence of an ancient or modern biosphere, significant quantities of organic material in the form of polycyclic aromatic hydrocarbons (PAH) from the interplanetary medium arrive daily on the Mars surface. • Viking chromatography/mass spectrometry failed to detect organic material including PAH at ppb levels. • The result led to a series of putative mechanisms for radiation destruction of organics on the regolith surface. • Theoretical calculations predict increased PAH survival as a function of depth in the regolith. Flynn, G. J. (1996) "The delivery of organic matter from asteroids and comets to the early surface of Mars. " Earth Moon Planets 72(1 -3): 469474. Biemann, K. , J. Oro, P. Toulmin III, L. E. Orgel, A. O. Nier, D. M. Anderson, P. G. Simmonds, D. Flory, A. V. Diaz, D. R. Rushneck, J. E. Biller and A. L. Lafleur ( 1977) "The search for organic substances and inorganic volatile compounds in the surface of Mars. " J. Geophys. Res. 82: 4641 -4658. Dartnell, L. R. , L. Desorgher, J. M. Ward and A. J. Coates (2007) "Modelling the surface and subsurface Martian radiation environment: implications for astrobiology. " Geophy. Res. Ltrs. 34: L 02207.
Organic Deposition On Mars from Meteorites, Micrometeorites, and Dust • ESA’s planned Exo. Mars mission will be first to sample regolith for organics at depths offering significant protection from surface radiation • The mission will include multiple technologies for detecting organics. However, all technologies either require sample preparation, expend limited consumables, and/or destroy targets of interest • Native autofluorescence is the single most sensitive method to detect aromatic organic compounds that does not require sample preparation or consumables or target destruction • PAH detection limit of <10 picogram. Storrie-Lombardi, M. C. , W. F. Hug, G. D. Mc. Donald, A. I. Tsapin and K. H. Nealson (2001) "Hollow cathode ion lasers for deep ultraviolet Raman spectroscopy and fluorescence imaging. " Rev. Sci. Ins. 72(12): 4452 -4459. Nealson, K. H. , A. Tsapin and M. Storrie-Lombardi (2002) "Searching for life in the universe: unconventional methods for an unconventional problem. " International Microbio. 5: 223 -230.
Science and Economic Drivers for Adding UV Laser Fluorescence Imaging Capability to Pan. Cam • PRIMARY SCIENCE DRIVER: Constrain models for organic infall and subsequent destruction as a function of depth into the Mars regolith • SECONDARY SCIENCE DRIVER: Sequential time series monitoring can detect biological UVphoto-damage and metabolic activity (NAD/FAD, photosystem pigments) -> Search for extant life Evaluating fluorescence in regolith extruded by drill. • ECONOMIC DRIVERS: - Optimize the use of precious expendables, thus lowering the mass requirement for these resources - Extend organic search capability to the maximum life of mission - Survey unsafe or unreachable targets of opportunity at a distance -> diminished risk to rover
Pan. Cam Epifluorescent Laser/LED Probes Pan. Cam currently provides several biological signatures using Absorption (Vis-NIR) • Motion 50 um Antarctic Cryptoendoliths 224, 248, 325 nm PAHs 365 nm 1 mm Suboceanic Basalts 325 nm 3 mm Cyanobacteria Mars Analog Basalt 375 nm Exo. Mars • Morphology • Complexity (Structural & Broad Chemical) Pan. Cam can provide more fundamental Astrochemical Signatures using Fluorescence Imaging (UV-Vis-NIR) • Ring Structures [PAHs, RNA, DNA, ATP] • Polymers [RNA, DNA, proteins, lipids] • Organosynthesis [chlorophyll, bacteriochlorphyll, accessory pigments] • Energy Transfer [NAD/NADH, FAD/FADH] • Diagenesis [porphyrins, kerogens]
Pan. Cam Fluorescence Astrochemical Targets Nominal Pan. Cam Filters Laser Excite (nm) • • 375 408 • 532 • 660 Napthalene Pyrene Perylene Anthracene Benzene Phenylalanine phycoerythrin Tyrosine phycocyanin - - Tryptophan Carotinoids - - -(Ribo)flavin- NADH (but not NAD) Chlorophyll a Chlorophyll b 250 300 350 400 450 500 550 600 650 Excite Wavelength (nm) 700 Absorption/Excitation Optima for Abiotic and Biotic Targets 750 800 850
Initial organic fluorescence experiments with single 365 nm LED & Beagle 2 filter wheel • Experiments performed in biotech laboratory (Gaia. Corp, San Diego, CA, 11/12/07) and in a desert environment (at Silver Lake, CA, 13/12/07) using 16 -bit digital camera and Beagle 2 flight-spare spectral filter-wheel (vis/NIR) • Organics (PAH, 2, 3, 4 benzene ring structures) determined at ppb (<µL concentrations) on bare rock using 365 nm LED at 50 -100 cm distance Muller and Storrie-Lombardi with the Beagle 2 flight-spare filter wheel at sunset at Silver Lake, Death Valley California for field tests
Fluorescence spectral signature of PAHs • Three PAH samples were doped on solid and ground Mars analogue rocks at different concentrations • Spectro-radiometric measurements performed of fluorescence signatures compared to Beagle 2 filters All Results from : Storrie-Lombardi, Muller, Fisk, Coates, Griffiths (GRL, 35, L 12201, 2008)
Fluorescence imaging signature of PAHs usingle 365 nm LED An 3 D surface representations of fluorescence in Red, Green, Blue Beagle 2/Pan. Cam filters for Anthracene, Pyrene, Perylene Py Pe B G R • detection limit for pyrene of 1. 5 ug at a camera-to-target distance of 1 meter in granular peridotite doped at pyrene levels of ~50± 5 ppm with single UV LED All Results from : Storrie-Lombardi, Muller, Fisk, Coates, Griffiths (GRL, 35, L 12201, 2008)
Fluorescence detection of PAHs in Death Valley • Assessed potential of UV fluorescence to detect PAHs in drill cuttings in Death Valley simulation. Very strong signature with starry night background. Digital 10 -bit camera (Foculus FO 432 SB) with Beagle 2 flight-spare filter-wheel under representative lighting conditions All Results from : Storrie-Lombardi, Muller, Fisk, Coates, Griffiths (GRL, 35, L 12201, 2008)
Fluorescence imaging detection limits of PAHs using 375 nm laser diode • We have now implemented the laser version of our UV fluorescence imaging system using a 375 nm Nichia laser diode. * • <3 gm • <1 cm 3 • no moving parts • Our initial detection limit experiments were performed on 3 PAH species doped onto granular peridotite with laser excitation at 375 nm, collection time 65 s, distance to target 2 metres PAH Rings DL (ppm) [green band] anthracene 3 69 pyrene 4 184 perylene 5 27 * Storrie-Lombardi, M. C. , Muller, J. -P. , Fisk, M. R. , Griffiths, A. D. , Coates, A. J. & Hoover, R. B. (2008) Epifluorescence surveys of extreme environments using Pan. Cam imaging systems: Antarctica and the Mars regolith Instruments, Methods, and Missions for Astrobiology XI (eds. Hoover, R. B. , Levin, G. V. & Rozanov, A. Y. ) 7097 (25): 1 -10 SPIE, San Diego.
Impact of Target Area on Detection Limits For any photonic probe sensitivity is directly dependent on the target area normal to the line of sight Experiment • Target: crystal pyrene • Excitation: 375 nm laser diode • Exposure time: 13 seconds • Pan. Cam green band detection Result: Detection fall off as a function of apparent area can be described by a second order polynomial: y = -0. 0029 x 2 + 48. 182 x - 2966. 6 R 2 = 0. 9998 The results underline the fact that we can expect increased sensitivity for W. A. L. I. if a target first imaged by Pan. Cam is then imaged by rover cameras with higher spatial resolution such as HRC or CLUPI.
UV Laser Diode Proposal • Attach a 375 nm UV laser diode next to each of the WAC filter wheels (shown here is the analogy with the Beagle 2 LED torch): • Wires to join filter wheel wires to PIU • Primary target : drill cuttings • Secondary targets: shadowed regions (under rocks, in crater overhangs) • Need laser (NOT LED) to obtain sufficient power for long range illumination • Multi-instrument examination possible (Pan. Cam, HRC, CLUPI) Beagle 2 showing LED “torch” UV location
UV Laser Diode (Nichia NDU 1113 E) • Class 3 UV laser diode • Diode weighs 0. 33 g • Diode control circuit weighs ≈1. 19 g • Mechanical support + heater ? ? ? • Tube+lenses ? ? g • Diode output power 20 m. W (max) • Diode requires a nominal power of 0. 3 W • Built-in photodetector to be used to maintain constant output
UV laser diodes: TRL 5 Readiness • Entire work funded and resourced from non-Pan. Cam resources as STFC requested • Mars chamber used to test laser diode survivability to -130ºC and 6 h. Pa pressure (N 2) Red laser: 4 thermal cycles tested over full T range UV laser: XX thermal cycles tested over range from -55ºC to +30ºC • Optical rig used to assess strength of fluorescence signature with PAH samples
Summary • This non-destructive organic detection technique searches the drill-cuttings as they first emerge to the surface • Rapid assessment (~60 s) does NOT require sample preparation or use of consumables (water, other solvents, reagents, stains) • Results will help allocate use of precious consumable resources required for more detailed organic assay • Optimizing consumable resources decreases mass requirement for these materials • Extends organic search capability to life of mission • Allows search of difficult targets (e. g. shadowed outcrops) while minimizing risk to rover • Could answer the most fundamental astrochemical paradox of the Mars regolith: Where are the organics?
Engineering Presentations on PDR assessment • • Electrical design (Kerrin Rees) Mechanical/thermal design (Chris B-B) Optical design for focusing (Dave Walton) Thermal cycling tests (Alex Rousseau)
Way Forward - Next Steps SCIENCE 1. 2. 3. 4. Development of a fluorescence database for anticipated Mars soil/PAH combinations - American collaborators Storrie-Lombardi and Fisk have applied for NASA Exobiology support for this effort. Muller plans UK project also. Development of a multivariate statistical and artificial neural network pattern recognition technique for target identification in real time - leverages off technique 1 for galaxy recognition; employed 2 for automated identification of biotic weathering of sub-oceanic basalts using elemental abundance distributions; will be implemented for W. A. L. I. as part of exobiology effort Development of automated fluorescent signature detection in Pan. Cam images using non neural network machine vision techniques developed at MSSL and CGI simulation using database results from US for determination of minimal detectability limits and optimum sampling strategies Data fusion by MSSL of Pan. Cam daylight multispectral images with fluorescent dusktime images to aid interpretation 1 Storrie-Lombardi, M. C. , Lahav, O. , Sodre, L. , and Storrie-Lombardi, L. J. (1992) Mon. Not. Roy. Astro. Soc. 259, 8 -12. Lahav, O. , Naim, A. , Buta, R. J. , Corwin, H. G. , de Vaucouleurs, G. , Dressler, A. , Huchra, J. P. , van den Bergh, S. , Raychaudhury, S. , Sodré Jr. , L. , and Storrie-Lombardi, M. C. (1995) Science 267, 859 -961 2 Storrie-Lombardi, M. C. and M. Fisk (2004). "Elemental abundance distributions in sub-oceanic basalt glass: evidence of biogenic alteration. " Geochem. Geophys. Geosys. 5(10): 1 -15, Q 10005, doi: 10. 1029/2004 GC 000755.
Way Forward ENGINEERING • Evaluation of temperature operational constraints • Design, construction and testing of heaters for focused and unfocused WALI • Thermal cycling through sufficient numbers of cycles to satisfy TRL 5 constraints • Modification of Pan. Cam PIU to accommodate needs of WALI • Modification of WAC optical bench CAD mechanical design to accommodate WALI-narrow & wide angle systems • Manufacture of 2 WALI systems and test up to TRL 5/6 • Integration of WALI in Pan. Cam optical bench and geometric calibration of system • Safe operation procedures for on ground system AIV testing with Class 3 UV lasers • Funding for all of the above including the UK science parts