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Space Life Support Technology Applications to Terrestrial Environmental Problems
Many of the problems now facing the human race on Earth are, in fact, life support issues. Decline of air Quality as a result of industrial and automotive emissions, pollution of ground water by organic pesticides or solvents, and the disposal of solid wastes are all examples of environmental problems that we must solve to sustain human life. The technologies currently under development to solve the problems of supporting human life for advanced space missions are extraordinarily synergistic with these environmental problems. The development of these technologies (including both physicochemical and bioregenerative types) is increasingly focused on closing the life support loop by removing and recycling contaminants and wastes to produce the materials necessary to sustain human life. By so doing, this technology development effort also focuses automatically on reducing resupply logistics requirements and increasing crew safety through increased self-sufficiency. This paper describes several technologies that have been developed to support human life in space and illustrates the applicability of the technologies to environmental problems including environmental remediation and pollution prevention.
Active anaerobic methane oxidation and sulfur disproportionation in the deep terrestrial subsurface
Abstract Microbial life is widespread in the terrestrial subsurface and present down to several kilometers depth, but the energy sources that fuel metabolism in deep oligotrophic and anoxic environments remain unclear. In the deep crystalline bedrock of the Fennoscandian Shield at Olkiluoto, Finland, opposing gradients of abiotic methane and ancient seawater-derived sulfate create a terrestrial sulfate-methane transition zone (SMTZ). We used chemical and isotopic data coupled to genome-resolved metaproteogenomics to demonstrate active life and, for the first time, provide direct evidence of active anaerobic oxidation of methane (AOM) in a deep terrestrial bedrock. Proteins from Methanoperedens (formerly ANME-2d) are readily identifiable despite the low abundance (≤1%) of this genus and confirm the occurrence of AOM. This finding is supported by 13C-depleted dissolved inorganic carbon. Proteins from Desulfocapsaceae and Desulfurivibrionaceae, in addition to 34S-enriched sulfate, suggest that these organisms use inorganic sulfur compounds as both electron donor and acceptor. Zerovalent sulfur in the groundwater may derive from abiotic rock interactions, or from a non-obligate syntrophy with Methanoperedens, potentially linking methane and sulfur cycles in Olkiluoto groundwater. Finally, putative episymbionts from the candidate phyla radiation (CPR) and DPANN archaea represented a significant diversity in the groundwater (26/84 genomes) with roles in sulfur and carbon cycling. Our results highlight AOM and sulfur disproportionation as active metabolisms and show that methane and sulfur fuel microbial activity in the deep terrestrial subsurface.
New Analyses of Diverse Hadean Zircon Inclusions from Jack Hills, Western Australia
The geological record is the only direct source of information regarding physical/chemical processes that may have ultimately been responsible for the origin of life. Known terrestrial rocks have ages that span from present day to approx. 4.0 Ga. This leaves a time gap of more than 500 Myr between lunar formation, and preservation of the oldest terrestrial crust. What were planetary conditions like wherein the prebiotic chemistry leading to life took place? The recent discovery of up to 4.37 Ga detrital zircons from Western Australia represents the only tangible record of the time period termed the Hadean Eon (4.5-4.0 Ga). Knowledge of the paragenesis of the oldest zircons potentially contributes information regarding the origin of the atmosphere, hydrosphere, continental lithosphere and the potential for life on the Hadean Earth.
A Direct Path to Finding Earth-Like Planets
As envisaged by the 2000 astrophysics decadal survey panel: The main goal of Terrestrial Planet Finder (TPF) is nothing less than to search for evidence of life on terrestrial planets around nearby stars . Here, we consider how an optical telescope paired with a free-flying occulter blocking light from the star can reach this goal directly, without knowledge of results from prior astrometric, doppler, or transit exoplanet observations. Using design reference missions and other simulations, we explore the potential of TPF-O to find planets in the habitable zone around their central stars, to spectrally characterize the atmospheres of detected planets, and to obtain rudimentary information about their orbits. We emphasize the importance of ozone absorption in the UV spectrum of a planet as a marker of photosynthesis by plants, algae, and cyanobacteria.
Siliceous Shrubs in Yellowstone's Hot Springs: Implications for Exobiological Investigations
Potential relict hot springs have been identified on Mars and, using the Earth as an analog, Martian hot springs are postulated to be an optimal locality for recognizing preserved evidence of extraterrestrial life. Distinctive organic and inorganic biomarkers are necessary to recognize preserved evidence of life in terrestrial and extraterrestrial hot spring accumulations. Hot springs in Yellowstone National Park, Wyoming, U.S.A., contain a wealth of information about primitive microbial life and associated biosignatures that may be useful for future exobiological investigations. Numerous siliceous hot springs in Yellowstone contain abundant, centimeter-scale, spinose precipitates of opaline silica (opal-A). Although areally extensive in siliceous hot spring discharge channel facies, these spinose forms have largely escaped attention. These precipitates referred to as shrubs, consist of porous aggregates of spinose opaline silica that superficially resemble miniature woody plants, i.e., the term shrubs. Shrubs in carbonate precipitating systems have received considerable attention, and represent naturally occurring biotically induced precipitates. As such, shrubs have great potential as hot spring environmental indicators and, more importantly, proxies for pre-existing microbial life.
Water as a Solvent for Life
"Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.
Editorial: Revisiting the limits of plant life - plant adaptations to extreme terrestrial environments relating to astrobiology and space biology
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Terrestrial central station array life-cycle analysis support study
Plant elements evaluated included designs for module, panel and array structures, as well as balance-of-plant systems. Installation and maintenance procedures and the impact of site environment were also evaluated. In terms of the cost of energy produced, the horizontal array configuration was found to be less expensive than the tandem array at latitudes less than 40 deg. Both of these configurations are less expensive than the rack design. However, the costs of energy for all three configurations are within approximately ?10 percent of each other. For flat plate panels, the seasonally adjusted and tracking array configurations are not economically attractive when compared to the three other designs. Balance-of-plant costs are approximately equal to (goal) module costs. The array structures and foundations are the most expensive items in the balance-of-plant costs.
Lunar base CELSS: A bioregenerative approach
During the twenty-first century, human habitation of a self-sustaining lunar base could become a reality. To achieve this goal, the occupants will have to have food, water, and an adequate atmosphere within a carefully designed environment. Advanced technology will be employed to support terrestrial life-sustaining processes on the Moon. One approach to a life support system based on food production, waste management and utilization, and product synthesis is outlined. Inputs include an atmosphere, water, plants, biodegradable substrates, and manufacutured materials such as fiberglass containment vessels from lunar resources. Outputs include purification of air and water, food, and hydrogen (H2) generated from methane (CH4). Important criteria are as follows: (1) minimize resupply from Earth; and (2) recycle as efficiently as possible.
The Search for Extant Life on Mars as a Focusing Scientific Goal for Future Human Exploration Missions
A search for evidence of extant life on Mars provides a focusing goal for human exploration missions that are planned for the 2030s. Finding an example of extant life beyond Earth would be one of the greatest scientific discoveries of all time. Human exploration brings extraordinary improvements over robotic missions in both payload and analytical capability. Environments that may be habitable for modern life on Mars include salts and brines, ground ice, caves, and deep subsurface aquifers [Carrier et al. 2020]. The habitability case for each environment is reviewed as well as how human missions may enable the search. It is important to determine if life exists on Mars prior to human exploration activities to prevent both the risk to Earth of inadvertently bringing potentially harmful organisms from Mars, risks to astronaut health, and the complication of recognizing Mars life once terrestrial contamination has occurred.
IVGen Mini Techport May 2024
Intravenous (IV) fluids are an important treatment modality for multiple medical conditions that have the potential to occur during Mars missions and that may lead to adverse crew health and mission outcomes without appropriate treatment. However, carrying sufficient volumes of IV fluids with adequate shelf life to support such missions is currently not feasible due to anticipated mass and volume constraints of future vehicles and the relatively short shelf-life of terrestrial IV fluids. The goal of the IntraVenous Fluid Generation for Exploration Missions, Miniaturized, (IVGen Mini) project is to develop a low mass and volume IV fluid generation device that can produce IV fluids in situ and that reduces the need to launch and store large quantities of IV fluids. It builds on the original IVGEN system developed by the Human Research Program’s Exploration Medical Capability Element that successfully demonstrated the capability to produce in-situ IV fluids aboard the ISS in 2010 using an ISS potable water source. Flight demonstration objectives for this system included purification via packed bed resin, bubble removal, sterilization, passive mixing in microgravity, and United States Pharmacopeia (USP) tested compliance. The project will culminate in a flight technical demonstration on the ISS in 2025/2026.
Microbial Diversity in Surface Iron-Rich Aqueous Environments: Implications for Seeking Signs of Life on Mars
The success of selecting future landing sites on Mars to discover extinct and/or extant extraterrestrial life is dependent on the correct approximation of available knowledge about terrestrial paleogeochemistry and life evolution to Martian (paleo) geology and geochemistry. It is well known that both Earth and Mars are Fe rich. This widespread occurrence suggests that Fe may have played a key role in early life forms, where it probably served as a key constituent in early prosthetic moieties in many proteins of ancient microbes on Earth and likely Mars. The second critical idea is the premise that Life on Mars could most likely have developed when Mars experienced tectonic activity [1] which dramatically decreased around 1 bin years after Martian creation. After that Martian life could have gone extinct or hibernated in the deep subsurface, which would be expensive to reach in contrast to the successful work of Martian surface rovers. Here we analyze the diversity of microbes in several terrestrial Fe rich surface environments in conjunction with the phylogeny and molecular timing of emergence of those microbes on Earth. Anticipated results should help evaluate future landing sites on Mars in searches for biosignatures.
The cratering record in the inner solar system: Implications for earth
Internal and external processes have reworked the Earth's surface throughout its history. In particular, the effect of meteorite impacts on the early history of the earth is lost due to fluvial, aeolian, volcanic and plate tectonic action. The cratering record on other inner solar system bodies often provides the only clue to the relative cratering rates and intensities that the earth has experienced throughout its history. Of the five major bodies within the inner solar system, Mercury, Mars, and the Moon retain scars of an early episode of high impact rates. The heavily cratered regions on Mercury, Mars, and the Moon show crater size-frequency distribution curves similar in shape and crater density, whereas the lightly cratered plains on the Moon and Mars show distribution curves which, although similar to each other, are statistically different in shape and density from the more heavily cratered units. The similarities among crater size-frequency distribution curves for the Moon, Mercury, and Mars suggest that the entire inner solar system was subjected to the two populations of impacting objects but Earth and Venus have lost their record of heavy bombardment impactors. Thus, based on the cratering record on the Moon, Mercury, and Mars, it can be inferred that the Earth experienced a period of high crater rates and basin formation prior to about 3.8 BY ago. Recent studies have linked mass extinctions to large terrestrial impacts, so life forms were unable to establish themselves until impact rates decreased substantially and terrestrial conditions became more benign. The possible periodicity of mass extinctions has led to the theory of fluctuating impact rates due to comet showers in the post heavy bombardment period. The active erosional environment on the Earth complicates attempts to verify these showers by erasing geological evidence of older impact craters. The estimated size of the impactor purportedly responsible for the Cretaceous-Tertiary mass extinctions is 10 km in diameter. Thus impactors greater than or equal to the size postulated for K-T impactor are rare within the inner solar system since the end of heavy bombardment.
Life on Mars
The Viking biology experiments are examined. It is noted that the Viking missions did not find a terrestrial type of life at either of the two landing sites. This evidence may suggest that Mars is lifeless, but science demands a more rigorous proof; thus, it is still not known whether life exists on Mars. It is suggested that the Martian polar regions must be explored before a conclusive answer is possible; the permanent polar caps of Mars are frozen water and would act as a 'cold finger' of the planet to trap organic molecules.
Constraining Venus Cloud Habitability: Earth's Aerobiosphere as an Analogue Environment
The potential habitability of Venus's cloud and haze layers has been debated for decades, with interest fueled by observations including disequilibria in atmospheric chemistry, strongly UV-absorbing particles, and (most recently) a controversial phosphine detection. Venus cloud temperature and pressure are clement by Earth standards; however, the calculated high acid activity and low water activity may exceed the limits of Earth biochemistry, based on observed life in extreme environments. A significant challenge in understanding Venus's habitability is the lack of an appropriate terrestrial analogue environment. Life has not been found in hydrothermal systems approaching Venus aerosol acidities, but these systems also contain high levels of other harsh solutes. Earth's stratospheric sulfate layer is a partial match in terms of acidity, desiccation, size, and isolation from the surface, but the few samples returned from these altitudes have yielded only sparse, inactive cells. Earth's tropospheric cloud droplets have an active microbial presence, but are larger and far more water-rich than Venus aerosols; tropospheric times aloft are also similar to microbial generation times, making Earth's aerobiosphere dependent on continuous surface replenishment. Direct detection of potential biosignatures from a single transect is challenging; Earth's cloud microbiota yields 102 - 108 viable cells per mL, equivalent to one per 103 - 109 particles, with highly dynamic and heterogeneous distribution. The most important in situ measurement for Venus cloud habitability is detailed aerosol composition: confirmation of acid and water activity, presence of potentially bioavailable nutrients and energy, and potential presence of organic matter. Modeling Venus cloud aerosol residence time in comparison to periodic influxes of water and photochemical energy, and thus the ability of an ecosystem to maintain itself over time, would also address a significant habitability constraint particular to aerobiospheres.
Building a virtual planet
The virtual Planetary Laboratory (VPL) is a recently funded 5-yr project, which seeks toimprove our understanding of the range of plausible environments and the likely signatures for life on extrasolar terrestrial planets. To achieve these goals we are developing a suite of innovative modeling tools to simulate the environments and spectra of extrasolar planets. The core of the VPL IS a coupled radiative transfer/climate/chemistry model, which is augmented by interchangeable modules which characterize geological, exogenic, atmospheric escape, and life processes. The VPL is validated using data derived from terrestrial planets within our own solar system. The VPL will be used to explore the plausible range of atmospheric composittions and globally averaged spectra for extrasolar planets and for early Earth, and will improve our understanding of the effect of life on a planet's atmospheric spectrum and composition. The models will also be used to create a comprehensive spectral catalog to provide recommendations on the optimum wavelength range, spectral resolution, and instrument sensitivity required to characterize extrasolar terrestrial planets. Although developed by our team, the VPL is envisioned to be a comprehensive and flexible tool, which can be collaboratively used by the broader planetary science and astrobiology communities. This presentation will describe the project concept, the tasks involved, and will outline current progress to date. This work is funded by the NASA Astrobiology Institute.
Heterococcus endolithicus sp. nov. (Xanthophyceae) and other terrestrial Heterococcus species from Antarctica: morphological changes during life history and response to temperature
Strains of Heterococcus endolithicus sp. nov., H. pleurococcoides Pitschmann, H. caespitosus Vischer, and H. protonematoides Vischer isolated from terrestrial habitats in Antarctica were studied in culture. Morphology of the algae changes with stage in life history. The characteristic branching patterns are not present in very young or old cultures. Filament formation is suppressed when cultures are grown outside their optimal temperature range.