Chemical, mineral and morphological biomarkers and microfossils are present in a wide variety of ancient rocks and meteorites. We discuss previous results and present images of microfossils of cyanobacteria, magnetotactic bacteria, and acritarchs detected in the Orgueil, Mighei, Nogoya, and Murchison carbonaceous meteorites.

The source of carbon of Early Archean graphites of Nimnyr suite of Aldan shield was cyanobacterial mat. In the region of its development there existed eucariots of diatoms type. It confirms the earlier supposition that eucariots were as ancient gropu of microorganisms as procariots. A well developed microbiota Early Archean means that there was no time for biopoese, forming cells and further evolution of organisms on Earth and consequently there was a possibility of bringing life to the Earth from Solar objects by representatives of all the three lines of microorganisms - arphea, bacteria and eucariots. The ability of bacterial organisms to form mineral-organic cocoons in transition to anabiotic state under conditions of permafrost as well as the ability of microorganisms remnants to preserve their biochemical peculiarities and cell structure that could be revived during long periods of geological age makes this possibility even more real. The evidence of microorganisms in ancient graphites enables us to refer these highcarbon formations to the rank of prospective objects for cognition of biological diversity of the Earth biosphere at the initial stages of its development.

Carbonaceous chondrites, a class of stony meteorites that contains up to 3 weight-% of organic carbon, are subdivided into types by chemical and mineralogical characteristics. These meteorites are thought to originate from asteroidal parent bodies on which secondary processing in the early history of the solar system has altered interstellar organic precursors into more complex compounds such as amino acids and nucleobases. We have analyzed nine different carbonaceous chondrites and have compared the total and relative amino acid concentrations of hydrolyzed hot-water extracts of these meteorites. When the relative amino acid concentrations [(Beta) -alanine]/[glycine], [AIB]/[glycine] and [D- alanine]/[glycine] of meteorites are plotted against each other, a clustering of the data points of the CM and CI type carbonaceous chondrites can be observed. This signature indicates that the amino acids in the Cms were synthesized via the Strecker synthetic pathway, whereas the amino acids found in the Cis probably have a different synthetic origin.

A number of landscape features of the surface of Mars have revealed similarities of morphology which may imply similarities of development and by and large, the presence of water, ice and permafrost. A systematic comparative study between landscapes of the Earth and those of Mars may be useful for the understanding of the evolution of Mars and the possible presence of global climatic changes on Mars. The comparative study along a landscape traverse from the poles till the equator on Earth can for this purpose successfully be compared with the Mars. It is concluded that Snowball Earth Stages similar to the Mars icy global stage today occurred periodically on Earth as well. Furthermore the evidence of melting water phenomena observed on Mars images point at protracted thawing inferring a Mars Global Warming today in resonance with the Earth.

Computing of periodicities in Mars sediment time series has been successful following a spectral analysis method that first was elaborated and tested on terrestrial deposits. In this paper the terrestrial method will first be explained on basis of fossil soil stratigraphic sequences mainly obtained from loess deposits on the Loess Plateau of China and the smaller Loess Belt of Northern France and Belgium. The computation method is called ExSpect: an Expert Spectral Analysis programme for cyclicity calculation. ExSpect was used for timespans and cyclicities of geological proxydata sets/time series behaving like acoustic signals. In applying this method on sediment time series of Mars image sediment sections a large cycle of 400Ka and two smaller ones of 4Ka and 9Ka (in Mars years) are computed like on Earth.

If Mars evolved from a warm, wet, and biologically active planet to the cold desert conditions we observe today, then the last remnants of life would certainly have adapted to extreme tundra-like conditions. Such adaptation might take the form of an ability to thrive in occasional summer meltwater pools, or even the ability to subtly modify its environment to encourage the formation and persistence of such pools. Surprisingly, recent evidence of ubiquitous gullies and seeps at high latitudes suggest that such seasonal melting may have persisted even to the present day. Calculations presented here give additional credence to that suggestion by demonstrating that water is sufficiently metastable to form seasonally recurring meltwater pools under thin crusts of ice on present-day Mars. Moreover, the simplest of biological mechanisms, by affecting evaporative cooling rates and emissivity, could both encourage and prolong the lifetime of such pools.

Scientific findings and theoretical analysis over the past several years have increased the probability from extant life on Mars. Discoveries have revealed terrestrial organisms flourishing in environments thought hostile and barren of life. Experiments with extremophile organisms, including some of those newly discovered, have demonstrated their extraordinary and unanticipated hardiness, including under conditions comparable to, or approaching those on present-day Mars. Microorganisms subjected to extreme g forces survived shock as severe as meteoric impact. Calculations and experiments based on Viking data allow for water to be liquid on the surface of Mars for biologically significant periods. Direct observations of Mars by subsequent missions support this likelihood. These new developments provide a workable Panspermia model for the transport, survival and growth of terrestrial life on Mars. No insurmountable obstacles to their survival to the present have been demonstrated. Organisms transported to Mars from Earch and/or from other sources may have been responsible for the positive results returned from Mars by the Viking Labeled Release experiment in 1976. A simple robotic experiment can resolve the issue.

The possibility that the positive outcome of the Viking Labeled Release Experiment (LR) had resulted from the presence of extant Martian microorganisms in samples examined on Mars was dismissed based largely on the failure of the Viking Gas Chromatograph-Mass Spectrometer (GCMS) to demonstrate the presence of organic mole-cules. More recent findings suggesting that the Viking GCMS would have missed such molecules if present necessitates a re-evaluation of the Viking LR data as well as a continued search for organic material and life at the Martian surface. In addition to advanced mass spectrometers to look for organic signatures of biological processes, future lander missions may use biological techniques, such as immunoassay, to directly detect bio-organic molecules. Meanwhile, several decades in advance of any planned sample return missions, the examination of Mars samples already present on Earth in the form of the SNC meteorites indicates that organic matter has existed in the Martian upper crust. It is concluded that a biological interpretation of the LR on Mars cannot be dismissed and should now be considered at least as plausible as a non-biological interpretation until more complete studies of the Martian sur-face are carried out.

Did Viking Lander biology experiments detect life on Mars? The strongest evidence for biology resulted from the Labeled Release (LR) experiment1. A radiolabeled (¹⁴C) nutrient solution was added to a Martian soil sample and the subsequent evolution of radioactive gas was observed. Flight data showed an initial release of labeled gas followed by strong periodic fluctuations in amount of gas in the headspace above the soil, superimposed on a slow rise in release. Current analyses show, at steady state, these fluctuations exhibit a periodicity of 24.66+/- 0.27 hr, statistically indistinguishable from the Martian solar period. The gas fluctuation appears synchronized to a mean 2 degree(s)C periodic fluctuation in internal temperature in the experimental chamber, which in turn is synchronous with almost 50 degree(s)C daily fluctuations in ambient Mars surface temperature. Calculations based on LR data indicate that the daily gas fluctuation amplitude could be in part accounted for by change in temperature-dependent soil solubility of CO₂, but total amount of gas accumulated cannot be accounted for in this way. Recent observations of circadian rhythmicity in microorganisms and entrainment of terrestrial circadian rhythms by low amplitude temperature cycles argue that a Martian circadian rhythm in the LR experiment may constitute a biosignature.

A review of the results of the Viking Biology experiments suggests that heterogeneous chemistry between the regolith and photochemically-produced oxidants best explains the data. Laboratory and numerical studies suggested that atmospherically-derived oxidants would neither survive long, nor diffuse deeply, into the martian regolith. Even including mechanical mixing, the total depth of the superoxidizing zone is likely to be no more than a few meters. Review of additional literature suggests that some of the species responsible for the Viking experiments may also have formed in situ, directly on the regolith material. These complexes form rapidly and abundantly when stimulated with UV photons, but significantly they can apparently form in lower abundances without UV stimulation from species known to be present in the martian atmosphere. This may help explain the small amounts of oxidant seen in the subsurface sample acquired by Viking. Critical laboratory data must now be gathered on the surface diffusion of chemisorbed O₂ radicals in multimineralic fines, in order to assess the potential mobility of this strongly oxidizing species at depth. In addition, adsorbents above and beyond TiO₂ must be examined for their interactions with a Mars-like chemical environment. If the mobility of the chemisorbed oxidants is low enough, relict organics could persist in regolith materials that would appear superoxidizing in Viking-like tests.

Many of the rocks on the surface of Mars that have been imaged by the Viking and Mars Pathfinder Landers display dark shiny surface coatings resembling Mn-rich terrestrial rock varnish. On our planet, these thin (5 um - 1 mm) coatings can be the result of a combination of various weathering processes combined with microbial precipitation of mineral oxides over a wide variety of geographical locations but most commonly in those with arid and semi-arid conditions. Terrestrial Mn-rich rock varnish is produced by a wide variety of microorganisms including epilithic and edolithic cyanobacteria, bacteria and microcolonial fungi. As these microorganisms absorb trace amounts of Mn and Fe from atmospheric dust, rain and fog, they slowly precipitate 'reddish' iron and 'brown to black' manganese oxides as well as magnetite particles. These microbial communities then produce secretions that cement the Mn/Fe mix together with clay particles in a process involving time periods of perhaps thousands of years for a thin 5 um layer. Mn-rich rock varnish has been found to form on the surfaces of undisturbed desert fragments and even sand grains. Both Mn and Fe would serve as a UV shield for any microflora residing beneath and within the layers of varnish thus protecting against high UV irradiation, dissication, and widely varying temperature extremes. Recent research on rock varnish has led to the discovery that some microbial communities that produce dark ferromanganese varnishes also precipitate biogenic magnetite. In view recent independent evidence put forth by D. McKay and E.I. Friedmann et al for indigenous biogenic magnetite-chains in ALH 84001 along with meteorological models showing the possibility for small quantities of liquid water on the surface of Mars in combination with data obtained from the Viking LR experiment 27 years ago, recommendations are made to elucidate on whether or not the shiny dark-coatings covering some Martian rocks have been produced by living or extinct microbial communities.

The new approach to search of traces of water on a surface of Mars is suggested based on variation of a water index obtained from the ratio of the images in close spectral ranges outside of and inside a band (940-980 nm) of absorption of water in vicinity of obertone of valence H-O vibrations, which previously was used for estimation of amount of water in leaves of terrestrial plants. It is revealed anomalously large (up to 1.2) value of water index in the region of a dark spot (181W37N) in Arcadia Platinia by the analysis of the ratio of the image of Mars at wavelengths 1042 and 953 nm, obtained with the help of the Hubble Space Telescope. The observed anomaly, which corresponds to almost 100 % contents of water in leaves on the Earth, is interpreted as result of the increased humidity of a surface or presence of a layer of liquid/bound water in this area of Mars resulting in reduction of efficiency of scattering of solar light with wavelength 953 nm due to increase of absorption in a band of obertone of vibrations of molecules of water.

Ever since the Viking Mission landed on Mars, a hypothetical film of highly oxidizing material has been applied to the Red Planet by a host of articles in the scientific literature. This putative chemical is credited with destroying all organic matter and preventing extant life. The only 'evidence' cited for the oxidant is a re-interpretation of the Viking biology experiments. On the other hand, direct experimental evidence from Mariner 9, Viking, Pathfinder, and Kitts Peak clearly demonstrate that Mars does not have a highly oxidative surface. This should remove the primary reason commonly cited against the Viking LR experiment having detected microorganisms in the Martian soil. For those requiring further evidence, an unambiguous test is proposed for the next Mars lander.

Direct detection of organic biomarkers for living or fossil microbes on Mars by an in-situ instrument is a worthy goal for future lander missions. We are developing a prototype instrument based on immunological reactions to specific antibodies to cause activation of fluorescent stains. We expect to propose a fully developed version of the instrument for inclusion on the 2007 Mars landing mission.

The Mars exploration strategy calls first for the detection from orbit of minerals indicative of environments conducive to the support of life or the preservation of biomarkers. That information would then be used for astrobiology landing site selection. The near-term search will be conducted by the 1996 Global Surveyor Thermal Emission Spectrometer (TES) and the 2001 Mars Odyssey 9-band radiometer Thermal Emission Imaging System (THEMIS). This places the productivity of TES and THEMIS in the critical path of the Mars astrobiology strategy. Most predictions of mineral detection limits for TES and THEMIS are based on laboratory spectra of fresh mineral surfaces. However, standard laboratory measurements of fresh mineral surfaces generally do not reproduce all the spectral effects of weathering and surface roughness that are very apparent in field spectra, and these differences can critically affect interpretations of TES and THEMIS data. Here we examine causes of variations in spectral contrast, and differences in spectral signatures recorded in the field and in typical laboratory measurements, and show what the results indicate for the search for minerals and landing sites using TES and THEMIS. We conclude that for TES and THEMIS to attain their predicted mineral detection limits, minerals must be present under specific conditions: well-crystalline, smooth-surfaced at several scales, and low atmospheric downwelling radiance contribution. As a result, TES and THEMIS should not necessarily be used to exclude landing sites that are of interest for other reasons (e.g. geomorphology), but that exhibit no clear detections of minerals of interest to astrobiologists.

The Astrobiology Explorer (ABE) is a MIDEX mission concept under study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp. ABE will conduct IR spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Cassegrain telescope and two moderate resolution (R equals 2000-3000) spectrographs covering the 2.5-16 micron spectral region. Large format (1024x1024 pixel or larger) IR detector arrays and bandpass filters will allow each spectrograph to cover an entire octave of spectral range or more per exposure without any moving parts. The telescope will be cooled below 50 K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to ~8K. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the ~1-2 year mission lifetime.

In this paper we review our current state of knowledge regarding the identity of organic and related compounds in the interstellar medium (ISM). The remote detection and identification of organics is ideally suited to the technique of infrared spectroscopy since such data can be obtained telescopically and this spectral range encompasses the fundamental vibrational modes of common molecular bonds. Despite recent advances in our knowledge of the organic component of the ISM, we are still far from understanding the distribution, abundance and evolutionary inter- relationship of these materials within our galaxy and the universe as a whole. Many of these issues can be addressed by the acquisition of new infrared spectra. We briefly describe a potential new Explorer-class space mission capable of obtaining such data, the AstroBiology Explorer (ABE) which consists of a space observatory capable of obtaining spectra in the 2.5-16.0 micrometers range at a spectral resolution of (Delta) $lamda/(lambda) equals 2000-3000. ABE would be capable of addressing outstanding problems in Astrochemistry and Astrophysics that are particularly relevant to Astrobiology and addressable via astronomical observation. ABE would have approximately one year lifetime during which it would obtain a coordinated set of infrared spectroscopic observations of large numbers of galaxies, stars, planetary nebulae, interstellar clouds, young star planetary systems and objects within our own Solar System.

Air samples collected aseptically over tropical India at various stratospheric altitudes ranging from 20 to 41 km using cryosampler assemblies carried on balloons flown from Hyderabad have shown evidence of living microbial cells. Unambiguous evidence of living cells came from examining micropore filters on which the samples were recovered with the use of voltage sensitive lipophilic dyes that could detect the presents of active cells. Clumps of viable cells were found at all altitudes using this technique, and this conclusion was found to be consistent with images obtained from electron microscopy. Since the 41 km sample was collected well above the local tropopause, a prima facie case for a space incidence of these microorganisms is established. Further work on culturing, PCR analysis and isotopic analysis is in progress.

It is suggested that life originated in a three-step process referred to as the jigsaw model. RNA, proteins, or similar organic molecules polymerized in a dehydrated carbon-rich environment, on surfaces in a carbon-rich environment, or in another environment where polymerization occurs. These polymers subsequently entered an aqueous environment where they folded into compact structures. It is argued that the folding of randomly generated polymers such as RNA or proteins in water tends to partition the folded polymer into domains with hydrophobic cores and matching shapes to minimize energy. In the aqueous environment hydrolysis or other reactions fragmented the compact structures into two or more matching molecules, occasionally producing simple living systems, also knows as autocatalytic sets of molecules. It is argued that the hydrolysis of folded polymers such as RNA or proteins is not random. The hydrophobic cores of the domains are rarely bisected due to the energy requirements in water. Hydrolysis preferentially fragments the folded polymers into pieces with complementary structures and chemical affinities. Thus the probability of producing a system of matched, interacting molecules in prebiotic chemistry is much higher than usually estimated. Environments where this process may occur are identified. For example, the jigsaw model suggests life may have originated at a seep or carbonaceous fluids beneath the ocean. The polymerization occurred beneath the sea floor. The folding and fragmentation occurred in the ocean. The implications of this hypothesis for seeking life or prebiotic chemistry in the Solar System are explored.

Transformation of organic and inorganic material in the atmosphere has been presumed to be caused by physical and chemical processes in the gas phase and in aerosol particles. Here we show that bacterial metabolism can play a measurable role in the production and transformation of organic carbon in cloud droplets collected at high altitudes, even at temperatures at or well below 0 degree(s)C. Although bacterial abundance and biomass in cloud water is low, compared to other oligotrophic aquatic environments, growth and carbon production rates per cell are approximately as high as in aquatic ecosystems. We hypothesize that microorganisms could play a crucial role in the transformation of airborne organic matter and the chemical composition of snow and rain. It has been recognized, the microbes can act as cloud condensation nuclei but we consider the impact on the global climate as low. With an increasing trend in cloudiness cloud systems can be seen as an ecosystem for active microbes with a seeding effort both for aquatic and terrestrial realms. Furthermore, air currents can distribute microbes over long distances to remote areas e.g. like ice caps and snow fields.

In this work the general conditions for some bodies of a solar System (Mars atmosphere, high Earth's atmosphere, the near-surface atmosphere of comets) at which one is possible formation of ordered structures in dusty plasma of lightning's. Existence of discharges in a dust-atmosphere of comets and at dust storms on Mars while only conjecture, but, despite of it the author has found possible to discuss conditions of formation of ordered structures from charged microparticles on these bodies of a solar System. The estimations of dusty plasma parameters originating at such discharges are made. On the basis of these estimations is drawn a conclusion that the dusty plasma in conditions of a Mars atmosphere, gas-dusty atmosphere of comets and in high layers of a Earth's atmosphere, will have properties, close to properties of laboratory dust plasma, in which one the ordered structures from charged microparticles are supervised.

Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Jo to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of To. There are extreme temperature variations on Jo' S surface - ranging from -130 °C to over +2000 °C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Jo. Hence Jo may have great significance to Astrobiology. Earth' s life forms that depend on sulfur respiration are members of two domainsBacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: a. the sulfur oxidizing process (occurring at aerobic conditions) and b. the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorinecontaining phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deep-sea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earths early evolutionary period.

An excess red emission of interstellar dust observed over the waveband 5000-8000A is well fitted in terms of photoluminescence of biologically derived chromophores. The redness of the class of Edgeworth-Kuiper belt objects and of areas of the Martian surface may have a similar explanation.

Azolla is an aquatic fern that contains a permanent endosymbiotic prokaryotic community (cyanobacteria and bacteria) inside of the cavity in the leaf dorsal lobe of the pteridophyte. This is a unique situation and can be seen as a microcosm inside of an organism and also can be considered a good example of a living model for biological and environmental studies. These symbionts are specific of this symbiosis and lives immobilized in a mucilaginous fibrillar network, which fills part of the cavity. The symbionts works as immobilized organisms in a natural system that can be used as a model for biotechnological research and in biologically based life support systems. The nature and the complexity of this system is simultaneously a reference and a challenge for the research in the communication between the two levels of nature organization (microcosm and mesocosm), and can also be used as a reference for the design of new environmental engineered symbiotic systems that include man as a prelude to life in space.

Extreme cold environments on Earth, such as polar regions or deep ocean harbor a variety of life forms that have developed unique molecular mechanisms that allow them not only to survive, but also to proliferate under hostile conditions. Such organisms are specially relevant to astrobiology studies because they help determine the environmental limits within which life can exist. They can also have a huge potential for biotechnological applications, because of the unique properties of their macromolecules. In this study we focused on a newly isolated bacterium from the Fox Permafrost Tunnel, FTR1, that grows anaerobically at +2 degree(s)C. We describe the molecular phylogenetic analysis of this microorganism, through the cloning, sequencing and analysis of its 16S ribosomal RNA gene. Our results suggests that FTR1 is a novel species belonging to the Carnobacterium genus.

We review the development of Bacterial Paleontology and consider its relevance of the rapidly emerging field of Astrobiology. We present electron microscopic images of fossil bacteria in different states of preservation in Earth rocks and Astromaterials.

Astrobiology is a new multi-disciplinary field of knowledge concerned with the study of the origin, distribution, and destiny of life in the universe and, naturally, in our planet. For this goal we must introduce and develop the adequate tools for teaching this science in schools and universities. New curricula, with a more open mind, must be established for the formation of the present and future generations of students and also, in our point of view, of teachers. One example of this effort can be seen in the Portuguese project A Journey to the Origins. Astrobiology in the Lab, where secondary school students recreate experiments regarding the Origin of Life and Cellular Evolution. The work will be widened to the educational community through the carrying out of Open Laboratory Sessions, conferences and the drawing up of a digital portfolio compiling all of the material developed by students and teachers throughout the project. A proposal will be made to restructure the curriculum to include a new unit entitled 'Astrobiology and Cellular Evolution'. The repercussions of this innovative paradigm could be seen in the future, not only in the educational community, but also in the society in general.

In January 2000, the Planetary Studies Foundation (PSF) of Algonquin, Illinois USA chose to extend its meteorite collecting efforts to the Thiel Mountains of Antartical, an area of known meteorite concentrations. The goal of this mission was to expand the previously searched blue ice areas at the Moulton Escarpment and to collect as many meteorites as possible. Two previous National Science Foundation search teams collectively recovered 36 meteorites. In five days of searching the PSF team collected 19 confirmed stone meteorites and two possible achondrites. Later evaluation and analyses of these specimens indicated that one of the original 19 stone meteorites, TIL 99002, was actually a rare achondrite and that the other two possible achondrites were not. Preliminary analyses indicate that TIL 99002 is either an acapulcoite or a lodranite, while the other two are terrestrial dacite or porphyritic andesite.

Microorganisms preserved within the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, asteroids, comets or other frozen worlds in the Cosmos. The psychrophilic and psychrotolerant microbes of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to where and how we should search for evidence of life elsewhere in the Universe. For this reason, the cold-loving microorganisms are directly relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years. Permafrost, ice wedges, pingos, glaciers, and polar ice sheets may contain intact ancient DNA, lipids, enzymes, proteins, genes, and even frozen and yet viable ancient microbiota. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below 0 degree(s)C. Complex microbial communities live in snow, ice-bubbles, cryoconite holes on glaciers and ancient microbial ecosystems are cryopreserved within the permafrost, glaciers, and polar caps. In the Astrobiology group of the NASA Marshall Space Flight Center and the University of Alabama at Huntsville, we have employed advanced techniques for the isolation, culture, and phylogenetic analysis of many types of microbial extremophiles. We have also used the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in ancient permafrost and ice. We discuss several interesting and novel anaerobic microorganisms that we have isolated and cultured from the Pleistocene ice of the Fox Tunnel of Alaska, guano of the Magellanic Penguin, deep-sea sediments from the vicinity of the Rainbow Hydrothermal Vent and enrichment cultures from ice of the Patriot Hills of Antarctica. The microbial extremophiles recovered from permafrost, ice, cold pools and deep-sea sediments may provide information relevant to the question of how and where we should search for evidence of extant or extinct microbial life elsewhere in the Cosmos.

The probable role of comets in formation prebiotic conditions on the Earth and Mars is analyzed. The exclusiveness of the Earth position in a solar System is considered from the point of view of interaction with comets and cometary head. As the intensive excretion begins with a surface of comets begins on a distance, comparable with spacing interval from the Earth up to the Sun, quantity of cometary gas and dust able to fall on the Earth and Mars can differ more than on the order. In particular, it concerns to substances accepting active participation in formation prebiotic conditions and synthesis of prebiological compounds (HCN, CH₃OH, H₂CO, CS, H₂S, HNC, CO). On an example of a Hole-Bopp comet in the work is made the comparison of quantity of a cometary's matter, which would drop out on a surface of the Earth and Mars in case of transiting a similar comet near to planets. It means that in case of influence of cometary's matter to forming prebiotic conditions on terrestrial planets, this influence for the Earth is much more, than for Mars.

Acritarchs are organic-walled cysts of unicellular protists that cannot be assigned to any known group of organisms. Most acritarchs are probably the resting cysts of marine eukaryotic phytoplankton. Some acritarchs are thought to be dinoflagellate cysts but lack the requisite morphology to make a positive attribution. Others, however, can be confidently assigned to the chlorophytes (green algae), but for convenience, are still commonly included in the acritarchs. Thus, acritarchs are a heterogeneous, polyphyletic collection of organic-walled microfossils of unknown or uncertain origin. Acritarchs vary in size from < 10 microns to more than 1 mm, but the majority of species range from 15 to 80 microns. Because of their small size, abundance and diversity, as well as widespread distribution, acritarchs are very useful in biostratigraphic correlation, as well as paleobiogeographic and paleoenvironmental studies. Acritarchs are found throughout the geologic column but were most common during the Late Proterozoic and Paleozoic. Because they represent the fossil record of the base of the marine food chain during the Proterozoic and Paleozoic, acritarchs played an important role in the evolution of the global marine ecosystem.

To produce definitive and unambiguous results, any life detection experiment must make minimal assumptions about the nature of extraterrestrial life. The only criteria that fits this definition is the ability to reproduce and in the process create a disequilibrium in the chemical and redox environment. The Life Detection Array (LIDA), an instrument proposed for the 2007 NASA Mars Scout Mission, and in the future for the Jovian moons, enables such an experiment. LIDA responds to minute biogenic chemical and physical changes in two identical 'growth' chambers. The sensitivity is provided by two differentially monitored electrochemical sensor arrays. Growth in one of the chambers alters the chemistry and ionic properties and results in a signal. This life detection system makes minimal assumptions; that after addition of water the microorganism replicates and in the process will produce small changes in its immediate surroundings by consuming, metabolizing, and excreting a number of molecules and/or ionic species. The experiment begins by placing an homogenized split-sample of soil or water into each chamber, adding water if soil, sterilizing via high temperature, and equilibrating. In the absence of any microorganism in either chamber, no signal will be detected. The inoculation of one chamber with even a few microorganisms which reproduce, will create a sufficient disequilibrium in the system (compared to the control) to be detectable. Replication of the experiment and positive results would lead to a definitive conclusion of biologically induced changes. The split sample and the nanogram inoculation eliminates chemistry as a causal agent.

The objective of the NASA Ames Kepler mission is the detection of extrasolar terrestrial-size planets through transit photometry. In an effort to optimize the Kepler system design, Ball Aerospace has developed a numerical photometer model to simulate the sensor as well as stars and hypothetical planetary transits. The model emulates the temporal behavior of the incident light from 100 stars (with various visual magnitudes) on one CCD of the Kepler focal plane array. Simulated transits are inserted into the light curves of the stars for transit detection signal-to-noise ratio analyses. The Kepler photometer model simulates all significant CCD characteristics such as dark current, shot noise, read out noise, residual non-uniformity, intrapixel gain variation, charge spill over, well capacity, spectral response, charge transfer efficiency, read out smearing, and others. The noise effects resulting from background stars are also considered. The optical system is also simulated to accurately estimate system optical point spread functions and optical attenuation. In addition, spacecraft pointing and jitter are incorporated. The model includes on-board processing effects such as analog-to-digital conversion, photometric aperture extraction, and 15-minute frame co-addition. Results from the model exhibit good agreement with NASA Ames lab data and are used in subsequent signal-to-noise ratio analyses to assess the transit detection capability. The reported simulations are run using system requirements rather than predicted performance to guarantee that mission science objectives can be attained. The Kepler Photometer Model has given substantial insight into the Kepler system design by offering a straightforward means of assessing system design impacts on the ability to detect planetary transits. It is used as one of the various tools for the establishment of system requirements to ensure mission success.