Indigenous embedded microbial filaments, bacterial cells and other microfossils were found in the Orgueil, Ivuna (CI1), Murchison, and Bells (CM2) carbonaceous meteorites. Biominerals, biofilms, framboids, magnetite platelets, and curious elemental iron ovoids covered with minute fibrils and carbon sheaths were also found. The S-4100 Hitachi Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray Analysis (EDAX) were used for in situ investigations of freshly fractured interior meteorite surfaces. EDAX x-ray spectra shows the microfossils bear signatures of the meteorite matrix and possess elemental ratios indicating they are indigenous and not recent microbial contaminants. Many of the well-preserved biogenic remains in the meteorites are encased within carbon-rich, sometimes electron transparent, sheaths. Their size, morphology and ultra microstructure are comparable to microfossils known from the phosphorites of Khubsughul, Mongolia and to some of the living cyanobacteria and other sulfur- and sulfate-reducing bacteria known from the halophilic Microcoleus mats of Sivash Lagoon, Crimea and from Mono Lake in California.

Elemental abundances (C⁶, N⁷, O⁸, Na¹¹, Mg¹², Al¹³, Si¹⁴, P¹⁵, S¹⁶, Cl¹⁷, K¹⁹, Ca²⁰, Ti²², Mn²⁵, Fe²⁶, and Ni²⁸) were obtained for a set of terrestrial fossils and the rock matrix surrounding them. Principal Component Analysis extracted five factors accounting for the 92.5% of the data variance, i.e. information content, of the elemental abundance data. Hierarchical Cluster Analysis provided unsupervised sample classification distinguishing fossil from matrix samples on the basis of either raw abundances or PCA input that agreed strongly with visual classification. A stochastic, non-linear Artificial Neural Network produced a Bayesian probability of correct sample classification. The results provide a quantitative probabilistic methodology for discriminating terrestrial fossils from the surrounding rock matrix using chemical information. To demonstrate the applicability of these techniques to the assessment of meteoritic samples or in situ extraterrestrial exploration, we present preliminary data on samples of the Orgueil meteorite. In both systems an elemental signature produces target classification decisions remarkably consistent with morphological classification by a human expert using only structural (visual) information. We discuss the possibility of implementing a complexity analysis metric capable of automating certain image analysis and pattern recognition abilities of the human eye using low magnification optical microscopy images and discuss the extension of this technique across multiple scales.

Carbonaceous meteorites are relics of ancient parent bodies from the time of formation of our solar system, approximately 4.5 billion years ago. They provide the best direct evidence for the organic inventory of the solar system prior to the evolution of habitable conditions for life on Earth and/or Mars and are often speculated as being a possible source of the organic matter from which life eventually emerged. Whether the residual organic matter in carbonaceous meteorites was derived in part from ancient extraterrestrial organisms or was entirely prebiotic in origin remains the topic of lively debate. Clearly, however, impact histories during the early stages of planet development logically point to some type of involvement of this material with respect to life's proliferation, either as a source or substrate. The compositions of CI and CM cabonaceous meteorites are assessed with respect to these two alternative scenarios.

Attempts to detect extraterrestrial life in-situ are complicated by the possibility of local geochemistry posing as biochemistry. A means is presented to discriminate biotic and abiotic signatures by the time resolved response of progressively smaller sample sizes when added to growth media. A purely geochemical response should show a linear reduction in response as the sample size decreases, however, the effects of saturation must be considered. A biochemical response should show a characteristic growth curve whose onset is progressively delayed with smaller sample sizes. Significantly, the overall shape of the growth curve would remain invariant. Potential complications include variations in growth dynamics such as short lifetimes and/or high mortality rates. A third case is also considered where both geochemical and biochemical responses are present. Experimental resulsts are presented using an electrochemical approach.

Investigation of the samples of the McArthur River complex ore deposit, one of the most zinc-lead mineral province in the world, brings us to conclusion about possibility of biogenic origin of sulfides in McArthur River ore deposit and to make supposition about formation of studied rocks in the photic zone of the sea.

I argue that much can be said about vision systems in general without invoking any particular instances Should astrobiology be lucky enough to encounter moderately advanced alien creatures (think salamanders not people), we will be able to understand their vision systems, however odd, as special cases of a very general procedure that any complex animal or system must use to operate in its world . Indeed, it is possible to illustrate that hypothesis with terrestrial examples of very weird visual systems that humans have created for animals. Also, many 21st Century machines exhibit primitive visual perception.

Jupiter's Icy Moons, Europa, Ganymede and Callisto, may possess energy sources, biogenic molecules, and oceans below their icy crusts, thus indicating a strong possibility that they were abodes for present or past life. Life in Earth's icy areas lives in a wide variety of habitats associated with the ice, in the water column below the ice, and on the floor of the ocean below the ice. Similar habitats may exist on JIM, have been transported to the icy crust, and be exposed in tectonic or impact features. Europa has a young, dynamic surface with many outcrops exposing older ice, fresh ice, possible materials from the subsurface ocean, and a few impact craters. Ganymede has older, darker, tectonized terrains surrounded by light ice. Callisto has a much older, heavily impacted surface devoid of significant tectonic structures. Past and present life habitats may be exposed in these features, making Europa the most favorable target while Ganymede is of interest, and Callisto seems more unlikely to have detectable life. A proper search strategy requires detailed orbital imaging and spectrometry of the likely places, and surface data collection with microscopic, spectrometric, and biochemical instruments.

We review the current state of knowledge concerning microbial extremophiles and comets and the potential significance of comets to Astrobiology. We model the thermal history of a cometary body, regarded as an assemblage of boulders, dust, ices and organics, as it approaches a perihelion distance of ~ 1AU. The transfer of incident energy from sunlight into the interior leads to the melting of near surface ices, some under stable porous crust, providing possible habitats for a wide range of microorganisms. We provide data concerning new evidence for indigenous microfossils in CI meteorites, which may be the remains of extinct cometary cores. We discuss the dominant microbial communities of polar sea-ice, Antarctic ice sheet, and cryoconite environments as possible analogs for microbial ecosystems that may grow in sub-crustal pools or in ice/water films in comets.

In January 2002 the Planetary Studies Foundation returned to Antarctica to conduct a systematic search for meteorites on the blue ice fields near the Pecora Escarpment. The Pecora Escarpment area was previously searched by two National Science Foundation (NSF) teams that collectively recovered 526 meteorites. The two primary goals of the PSF Antarctica 2002 expedition were to determine if a significant number of meteorites could be found in a previously searched area, and to collect ice core samples to determine the presence or absence of microbial life. Several days' fieldwork resulted in the recovery of 33 meteorites, which included one stony-iron, two achondrites, an enstatite chondrite, and the collection of numerous ice samples. One particularly intriguing question that needed to be answered concerned the possibility that microbial life present in the ice may contaminate the meteorites. Antarctica was once considered to be a pristine environment with little or no biological contamination. This concept was particularly significant to the study of carbonaceous chondrites in order to insure that the organic compounds present in the meteorite were truly extraterrestrial in origin and not a product of terrestrial contamination. The preliminary results of this study indicated that microbial life was present in every ice sample.

NASA has frequently stated that its highest priority is the search for extraterrestrial life. However, no life detection instruments have been sent to Mars since the Viking Mission in 1976 produced highly disputed evidence for microbial life in the Martian soil. The unfortunately lost Beagle 2 and the successfully landed Spirit and Opportunity are all devoid of means to investigate the Viking findings or otherwise to determine whether or not life exists or ever existed on the red planet. However, all of these spacecraft contain instruments that are designed to obtain data ancillary to that vital and supreme question. Imaging and spectral data have now arrived from the European Space Agency's orbiter, Mars Express, and from NASA's Mars Exploration Rovers Spirit and Opportunity. These data are discussed from the standpoint of their impact on the prospects for life on Mars, and, specifically, on the 1976 Viking Labeled Release (LR) experiments that the author claims proved the presence of active microbial life in the topsoil of Mars.

One of the most enigmatic discoveries made by the NASA Mars Exploration Rover Opportunity (MER-B) at the Meridiani Planum landing site are the ubiquitous spherules referred to as "blueberries" by the science team. They cover the entire landing area and can be seen in every direction within view of the rover cameras. Subsequent analysis of a small grouping of the spherules laying on top of a rock outcrop by Mossbauer spectroscopy showed an intense hematite signature not found on the rock or in the surrounding basaltic soils. Spherules were also found attached to and embedded within sedimentary sulfate rock outcrops found at the landing area that have been determined by the MER science team as having been formed in an acidic liquid water environment. The appearance of most of the Meridiani spherules is strikingly similar to the morphology and size of terrestrial accretionary lapilli and show similarities to terrestrial tektites. Accretionary lapilli are spherical balls and fragments with a concentric layered structure that are formed by a variety of mechanisms including hydrovolcanic eruptions, geysers and large meteorite impacts in water. Tektites are glassy impact spherules that form as a result of large meteorite impacts and also seem apparent in some of the rover images. Tektites can be perfectly spherical or have teardrop and dumbbell shapes. A lack of a visible volcanic source capable of producing high volumes of accretionary lapilli as seen in the MER-B images, in combination with the strong spectral signature of hematite, that some of the spherules display, led the MER science team to favor a concretion hypothesis thus far. All of these types of spherules involve interaction of with surface water or ice to form. Problems exist in explaining how the Martian “concretions”, if that is indeed what they are, are of such uniform size and have such a wide distribution. Evidence from Martian orbit and on the surface indicate that the Meridiani Planum landing ellipse is located within an ancient 800 km diameter impact structure with another 140 km crater under the site. Estimated hydrothermal output from this size of an impact would be equivalent to 38 times Yellowstone over a 15,000 year time period. Life as we understand it is dependent on a source of liquid water, energy, and nutrients. Hydrothermal energy can originate from either internal volcanic sources or through the action of large bolide impact. A 25 km diameter fluidized ejecta (rampart) crater named Victoria is located 50 km to the southwest of the Opportunity rover landing site and might explain how the Meridiani Planum region is covered with such an enormous abundance of spherules.

In January of 2004 NASA was directed by the President of the United States to setting a goal to establish a permanent human tended scientific outpost on the Moon by 2015-2020. Discussions on what kind of facilities on the Moon would be most beneficial to science have already begun. One of the highest priority goals for the NASA Mars exploration program has been how to proceed with the return of Martian soil and rock samples directly to Earth for extensive laboratory analysis. However scientific debates exist on how to obtain pristine samples from Mars without introducing terrestrial contaminants and also for preventing the back contamination of the Earth’s biosphere by putative Martian microbes. In 1976, the Viking Labeled Release experiment provided peer-reviewed scientific evidence for possible microbial activity in the upper soil layers of Mars in two different locations on the planet. Although the LR evidence is not considered as absolute proof of life on Mars by many in the scientific community, the Viking LR data should be taken seriously as an important signpost that life, either as dormant endospores (which may have been revived on the addition of the LR nutrient solution), or found as a currently thriving microbial community, might pose a serious risk to the terrestrial biosphere in the event of a sample return spacecraft failure. Examples of spacecraft technological failures include most recently the British built Beagle 2 lander, the NASA Mars Climate Orbiter and Mars Polar Lander. These examples show there is no guarantee of a 100% foolproof spacecraft. In 2001 the Space Studies Board of the National Research Council published that the likelihood of life on Mars is low, "but it is not zero" and proposed the construction of a level-4 biohazard containment facility "like no other on the Earth". Since at this time we cannot guess whether any putative Martian organisms would be toxic or pathogenic to Earth life, every effort should be made to ensure that the terrestrial biosphere is not contaminated. Recent Mars Sample Return (MSR) scenarios have focused on a direct return to the surface of the Earth by means of a passive reentry capsule similar to the Stardust sample capsule but designed to use atmospheric friction and ablating to slow its decent instead of a parachute. This scenario offers less planetary protection than LEO examination by a specially trained scientific crew aboard the ISS or space shuttle. While a number of Mars Sample Return strategies have been published since the 1976 Viking mission, probably the most comprehensive concerning examination in LEO is the 1981 The Antaeus Report: Orbiting Quarantine Facility (NASA SP-454). Although the Antaeus Report demonstrated the feasibility of examining planetary samples in LEO it did not offer Earth's biosphere maximum protection against back contamination hazards due to possible catastrophic failure and reentry of the orbiting quarantine facility or space shuttle. A human tended Planetary Quarantine Laboratory as part of a scientific outpost on the Moon would offer 100% protection of Earth's biosphere against any toxic or pathogenic bioactive materials from Mars or any other solar system samples returned.

A permanent ice covered water body, called Lake Paula, was detected in Patriot Hills in the West Antarctic and sampled for the first time ever for microbial life. The ice sheet measured approximately 2,5m thickness and the water body has a depth of about 10m. The lake is situated near a moraine which partly ablates from snow and provides meltwater from the slopes to the lake during austral summer. These running waters which are kept liquid by the heating up of the dark soil are penetrating the lower ice cover and thus softening up the lakeside part if the ice core. It is inoculated by nutrients, active microbes and diatoms of terrestrial origin. A distinct gradient concerning bacterial numbers, biomass and production which is 10 fold at the ice-water interface compared to the exposed part is observable. Temperature sensitivity of the embedded microbes reflect the gradient as well: Bacteria isolated from the upper part showed growth optima at 10°C, the lower part at 25°C, phylogenetic properties done by 16s rDNA reveal distinct communities depending on their vertical position, some clones are similar to those retrieved in Lake Vostok ice cores. These results offer the conclusion that even in this harsh environment like the Antarctic continent a dynamic system like microbial ice aggregates can be sustained as long as the supply of liquid water which is essential for an active bacterial metabolism is provided at least for a small time frame.

Psychrotolerance, as an adaptation for surviving in extreme environments, is widespread among mesophilic microorganisms. Physico-chemical factors such as pressure, red-ox potential, pH and salinity could significantly alter the features of ecosystems by providing liquid water at subzero temperatures. Furthermore, organisms can respond to temperature changes by several known mechanisms, including changing the conformation capacities of constitutional proteins or by the synthesis of mucopolysaccharides around the cell wall and membrane. Such protective mechanisms make it possible for cells to not only passively survive low temperatures in a state of anabiosis, but also to be capable of actively metabolizing substrates and reproducing normally. The physiological and biochemical characteristics of the species, as well as genetics, could be remarkably changed due to adaptation and surviving in extreme environments. The cold shock genes of some of the studied strains of psychrotolerant facultative anaerobes were reported previously. In this paper we present experimental data for psychrotolerant, non spore-forming, facultative anaerobes isolated from geographically different cold regions of our planet. We show the growth response on changing from anaerobic conditions to aerobic with cultivation at low temperatures.

Hydrogenase is the key enzyme of energetic metabolism in cells, catalyzing the converse reaction of hydrogen oxidation and responsible for the consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins, most of which contain either nickel and iron or iron alone in their active center. Hydrogenases have been found in many microorganisms, such as methanogenic, acetogenic, nitrogen-fixing, sulfate-reducing, photosynthetic bacteria, and algae that use the hydrogen as an energy source or as an electron sink. Hydrogenases are the subject of wide physiological, biochemical, physico-chemical and genetic studies due to their abilities to produce molecular hydrogen as an alternative source of energy. Despite the large quantity of work dealing with the intracellular and extracellular enzymes of halophilic bacteria, the data about the response of hydrogenases to salts are practically absent. The study of hydrogenase in cell-free extracts of the extremely halophilic eubacterium Acetohalobium arabaticum showed a dramatic increase in the activity of the enzyme at high concentrations of NaCl and KCl (near saturated solutions). Here we present data about hydrogenase in a free-cell extract from the new halo-alkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grows on a highly mineralized carbonate-bicarbonate medium in the salinity range from 1 to 7 % NaCl and at pH 8.0-10.0. The studied enzyme was active in concentration range from 0.0 to 4.3 M NaCl with the optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme expressed 20 % additional activity, with NaCl concentration changing from 2.1 M to 3.4 M, and then the activity decreased and reached a constant level. Although sodium bicarbonate decreases the hydrogenase activity, the enzyme still showed activity at 60 % of the maximum level at concentration in a near saturated solution (1.2 M NaHCO₃). The maximum enzyme activity was observed at pH 9.5 with limits of 7.5 and 11.5, which is practically equal to the pH optimum of bacterial growth. Therefore the hydrogenase of D. thiodismutans is extremely tolerant to high concentrations of sodium salts and resistant to high pH, which makes it a unique subject for biochemical research with the possibility of important biotechnological applications.

In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data with the rates of hydrogen productivity for S. americana ASpG1 isolated from soda Mono Lake in California.

Due to the highly stringent requirements on planet-detecting nulling interferometers, many approximations made for standard imaging systems are no longer valid. Analyses using scalar electric fields must be modified to employ vector (polarized) electric fields. In this paper, we present definitions of Stokes-related vectors, Mueller matrices, and the responses (scalar and vector) of single- and dual- Bracewell instruments. We study systematic errors due to instrumental polarization, discussing mismatched elliptically polarized arms, misaligned mirror trains, and beam non-uniformities. Also, we consider systematic errors due to interstellar polarization and polarized starspots. Last, we briefly discuss ancillary science projects that are possible with a space-based interferometer and polarimeter.

This overview paper describes the system design of the structurally-connected interferometer (SCI) concept studied for the Terrestrial Planet Finder (TPF) project. This paper covers progress since August 2003 and serves as an update to a paper presented at that month's SPIE conference, "Techniques and Instrumentation for Detection of Exoplanets". SCI trade studies conducted since mid-2003 have focused on key factors driving overall flight segment mass and performance, including launch vehicle packaging, structural design, and instrument layout. This paper summarizes the results of the recent design trades, with discussion of the primary requirements that drive the baseline design concept.

One of NASA's two planet-finding missions will be an optical coronagraph. Due to the stringent science requirements, i.e., detecting a planet that is more than a billion times fainter than its parent star, effects that normally do not enter into instrument design must now be considered. One such effect is polarization. This paper has several goals. First, we review scalar diffraction theory (PSFs and Strehl ratios) and extend it to include polarization. Second, we employ a systems-engineering approach to subdivide and categorize instrumental effects, ultimately concentrating on polarizing non-coronagraph components (mirrors). Third, we push the limits of Code-V commercial optical-engineering software to model the polarization behavior for on- and off- axis configurations, using protected-silver and bare-gold mirror coatings at four wavelengths. Last, we present a brief discussion of future tasks: easing polarization requirements, source polarization, and coronagraph masks and stops.

The optical telescope for a spaceborne coronagraph to detect terrestrial to Jovian-sized planets has unusually stringent phase and amplitude requirements - far exceeding a "conventional" telescope like Hubble or the James Webb Space Telescope. The key engineering requirements will be summarized based on probable mission science objectives and an engineering solution with a monolithic primary mirror on the order of 6 meters by 4 meters. We will also present an optical design for a sub-scale coronagraphic simulator as a logical and essential step in examining the system sensitivities. Testbed simulations will include F, G, and K stars and companion planets ranging in size from earth-like up to Jovian-like.

Proposed geochemical histories for the evolution of Mars offer the possibility that the planet may have experienced conditions remarkably similar to those faced by life on Earth during Archean and Proterozoic eons. For almost two billion years microbial mat communities dominated by photosynthetic cyanobacteria were the dominant life forms on Earth. Descendents of these complex communities and the fossil remnants of their ancestors can be found today in Northwestern Australia. These sites offer a unique testing ground for developing integrated remote and in situ methods for identifying sites of geobiological interest during exploration of Mars, the Jovian or Saturnian satellites, or neighboring extra-solar planetary systems. We are currently performing remote and in situ analyses of spectral and image data from the Trendall locality of NW Australia, an area rich in geobiological targets including hydrothermally altered basalts, fossil stromatolites and pillow basalts. We discuss the early results of employing cluster analysis, Bayesian probabilistic estimators, and complexity analysis techniques to analyze remote and in situ photographic and spectral data. The techniques presented offer a systematic methodology for both the remote selection of landing sites most likely to contain targets of geobiological interest and the in situ identification of aqueous or biologically altered samples.

Correct color calibration of images sent from Mars is essential to their usefulness in providing mineralogical, geochemical, chemical and, possibly, biological information. This paper demonstrates the impact of correct calibration on the Viking Mission images. The color charts imaged by the Viking Landers are compared to the color chart on the duplicate Viking Lander at the Smithsonian. When the R, G and B levels obtained from the gray panels are aligned, good agreement is found with the Martian red color panel. The B and G color panels in the Viking image "raw data" as published, however, appear greatly dissimilar to the actual panels viewed on Earth. An excess of red is found on all of the Martian blue and green panels. Limits on the multiplicative intensity properties are derived showing that only extreme red illumination could change the Martian B and G color charts so dramatically. Such extreme illuminations are shown to be incompatible with the gray panels. It appears that the true raw image data have been modified prior to publication to convert the blue and green pixels to gray, rendering a grossly changed image.

The controversy about color Mars lander image calibration, begun in 1976 during the Viking mission, continues with the 2004 Spirit and Opportunity missions. Officially released color images at web site "Photojournal.JPL.NASA.Gov" continue to show wide variation. Two sets of filters are used by NASA to produce color images from Spirit. One conventional set of red, green and blue filters has been used for images of the calibration chart alone and small pieces of the soil. Another set of infra-red, green and blue filters is used for larger panoramic images. While most objects in the Martian scene are not affected by this change, the appearance of the color calibration chart changes drastically. An extreme example of this can be found in the comparison of the blue color panel using the two different sets of filters. When the blue panel is seen in the panorama images, it appears to be bright red. Small blue wire ties on the rover also appear to be bright red in the panoramas. NASA claims that the blue color panel is unusually reflective in the near infra-red. This makes inspection of the color balance more difficult and many problems exist in published "true color" images. This paper will round up this and other issues involving Spirit color image calibration.

The science capabilities and features of an innovative and revolutionary approach to remote sensing imaging systems aimed at increasing the return on future planetary science missions many fold are described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional space telescopes, by integrating advanced optical imaging interferometer technologies into a multi-functional remote sensing science payload. MIDAS acts as a single front-end actively controlled telescope array for use on common missions, reducing the cost, resources, complexity, and risks of developing a set of back-end science instruments (SIs) tailored to each specific mission. By interfacing to multiple science instruments, MIDAS enables either sequential or concurrent SI operations in all functional modes. Passive imaging modes enable remote sensing at diffraction-limited resolution sequentially by each SI, as well as at somewhat lower resolution by multiple SIs acting concurrently on the image, such as in different wavebands. MIDAS inherently provides nanometer-resolution hyperspectral passive imaging without the need for any moving parts in the SI's. Our optical design features high-resolution imaging for long dwell times at high altitudes, <1m GSD from the 5000km extent of spiral orbits, thereby enabling regional remote sensing of dynamic planet surface processes, as well as ultra-high resolution of 2cm GSD from a 100km science orbit that enable orbital searches for signs of life processes on the planet surface. In its active remote sensing modes, using an integrated solid-state laser source, MIDAS enables LIDAR, vibrometry, surface illumination, ablation, laser spectroscopy and optical laser communications. The powerful combination of MIDAS passive and active modes, each with sequential or concurrent SI operations, increases potential science return for space science missions many fold. For example, on a mission to the icy moons of Jupiter, MIDAS enhances detailed imaging of the geology and glaciology of the surface, determining the geochemistry of surface materials, and conducting seismic and tidal studies.

Microbial activity in subsurface basalts produces characteristic alteration in the volcanic glass readily observed in petrographic microphotographs. Basalts containing volcanic glass cored from three different sites beneath the ocean floor along a mid-ocean ridge exhibiting such alteration was determined to also exhibit co-registered regions of elemental abundance alteration. Further investigation one of these sites presenting examples of all three states (unaltered glass and glass altered to produce clays by abiotic and biotic processes) now reveals that lossless compression analysis of the RGB photomicrographs detects significant differences between altered and unaltered basalt glass. The technique can distinguish images of all three groups without knowledge of the opinion of the expert human observer. Electron microprobe elemental abundance measurements were obtained from sites in all three regions. Principal Component Analysis using eleven elements as input (Na¹¹, Mg¹², Al¹³, Si¹⁴, P¹⁵, Cl¹⁷, K¹⁹, Ca²⁰, Ti²², Mn²⁵, and Fe²⁶) extracted two factors accounting for more than 75% of the data variance. When these same elements were used as inputs to a Hierarchical Cluster Analysis algorithm to provide unsupervised sample classification all samples clustered as predicted both by human visual observation and complexity analysis prediction. Finally, the PCA components extracted were used as inputs to a stochastic, non-linear and Artificial Neural Network to produce a Bayesian probability of correct classification. The technique provides a quantitative methodology for discrimination of biotic and abiotic alteration of sub-ocean basalt glass using both structural and chemical information.

Ribose readily makes complexes with borates, silicates, and calcium. Borate and silicate complexes stabilize and preserve ribose under simulated prebiotic conditions. We report here the C-13 NMR study of the ribose calcium complexes. Calcium ions form complex with teh beta-furanose form of ribose, which is biologically relevant, in the following way. The C-2 and C-3 hydroxyl groups get involved in making the complex, while the C-1 OH remains uninvolved. This allows the C-1 OH, which is the most reactive, anomeric hyroxyl, to react further to make prebiotic nucleosides. Thus, the complexation of calcium with ribose may be responsible for the selection of the beta-furanose form in biology.

Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which the rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of the polymerization of silicic acid with the biooganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the natural ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly on Mars.

Diagenetic hematite concretions are common in the eolian Jurassic Navajo Sandstone in southern Utah (and some correlative units in Arizona and Nevada). The zones of alteration formed by structurally and stratigraphically influenced subsurface groundwater flow and localized iron oxide precipitation within porous sedimentary rocks. In many geologic systems on Earth, iron is a sensitive fluid flow indicator1. Mobilization and precipitation of iron oxides and sulfides requires specific variations in fluid chemistry. Precipitation of iron oxides in discrete concretionary zones further requires specific host rock characteristics. These characteristic color variations and zones of mineralization in the Jurassic Navajo Sandstone occur in a variety of cementation patterns with structural and stratigraphic relationships that have been well documented. Iron for the concretions is likely sourced internally from hematite grain coatings. Near surface, meteoric waters and processes of weathering commonly distribute disseminated iron films that impart a pink to orange-red color to the sandstone early in the depositional or burial history. The disseminated iron oxides are commonly mobilized and removed by reducing fluids, leaving the sandstone white. When these fluids mix with oxidizing groundwater in the Utah example, concentrated hematite precipitates, typically in the form of spherical balls. Many other concretion geometries commonly occur where anisotropy and preferential fluid flow pathways exist. Some of these shapes include pipes, sheets, bulbs, angular bricks, and repetitive bands. The differing geometries appear to be primarily a function of permeability barriers and pathways. Both sandstone coloration and the presence of hematite concretions (+/- other iron oxide minerals) record evidence of past fluid flow and reactions in subsurface sedimentary rocks. These are products of low-temperature, near-surface, hydrologic, chemical diagenetic reactions. Biomediation can also enhance the diagenetic precipitation of cements. In addition to elucidating a complex history of fluid flow in Utah subsurface, analysis of these concretions can help us to better understand the recently discovered hematite concretions on Mars. The NASA Mars Exploration Rover (MER), Opportunity has discovered spherical nodules in Meridiani Planum, that have been identified to be predominately hematite in composition5,6. These Mars concretions bear a remarkable resemblance to hematite-cemented concretions in sandstones of southern Utah. Hematite is one of few minerals currently found on Mars that can be genetically linked directly to water-related processes7. Although the general process of chemical precipitation has been proposed, diagenetic concretionary precipitation, or ferruginization, has been previously overlooked as a potential formation mechanism. This terrestrial analog in Utah has important implications for biomediated precipitation and for subsurface and potentially atmospheric chemical conditions on Mars.