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Atmospheric methane has been increasing since the beginning of the industrial era due to anthropogenic emissions. Methane has many sources, both natural and anthropogenic, and there continues to be considerable uncertainty regarding the contribution of each source to the total methane budget. Thus, remote sensing techniques for monitoring and measuring methane emissions are of increasing interest. Recently, the Airborne Visible-Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG) has proven to be a valuable instrument for quantitative mapping of methane plumes. Despite this success, uncertainties remain regarding the sensitivity of the retrieval algorithms, including the influence of albedo and the impact of surfaces that may cause spurious signals. To explore these sensitivities, we applied the Iterative Maximum a Posterior Differential Optical Absorption Spectroscopy (IMAP-DOAS) methane retrieval algorithm to synthetic reflected radiances with variable methane concentrations, albedo, surface cover, and aerosols. This allowed for characterizing retrieval performance, including potential sensitivity to variable surfaces, low albedo surfaces, and surfaces known to cause spurious signals. We found that dark surfaces (below 0.10 μWcm^(−2)nm^(−1)sr^(−1) at 2139 nm), such as water and green vegetation, and materials with absorption features in the 2200–2400 nm range caused higher errors in retrieval results. We also found that aerosols have little influence on retrievals in the SWIR. Results from the synthetic scene are consistent with those observed in IMAP-DOAS retrievals for real AVIRIS-NG scenes containing methane plumes from a waste dairy lagoon and coal mine ventilation shafts. Understanding the effect of surface properties on methane retrievals is important given the increased use of AVIRIS-NG to map gas plumes from a diversity of sources over variable landscapes.

Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit [Formula: see text] 2 kg/h to 5 kg/h through [Formula: see text] 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. With the observed confirmation of a lognormal emission distribution, this airborne observing strategy and its ability to locate previously unknown point sources in real time provides an efficient and effective method to identify and mitigate major emissions contributors over a wide geographic area. With improved instrumentation, this capability scales to spaceborne applications [Thompson DR, et al. (2016) Geophys Res Lett 43(12):6571-6578]. Further illustration of this potential is demonstrated with two detected, confirmed, and repaired pipeline leaks during the campaign.

Emissions estimates of anthropogenic methane (CH 4 ) sources are highly uncertain and many sources related to energy production are localized yet difficult to quantify. Airborne imaging spectrometers like the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) are well suited for locating CH 4 point sources due to their ability to map concentrations over large regions with the high spatial resolution necessary to resolve localized emissions. AVIRIS-NG was deployed during a field campaign to measure controlled CH 4 releases at the Rocky Mountain Oilfield Testing Center (RMOTC) in Wyoming, U.S. for multiple flux rates and flight altitudes. Two algorithms were applied to AVIRIS-NG scenes, a matched filter detection algorithm and a hybrid retrieval approach using the Iterative Maximum a Posteriori Differential Optical Absorption Spectroscopy (IMAP-DOAS) algorithm and Singular Value Decomposition. Plumes for releases as low as 14.16 m 3 /h (0.09 kt/year) were consistently observed by AVIRIS-NG at multiple flight altitudes and images of plumes were in agreement with wind directions measured at ground stations. In some cases plumes as low as 3.40 m 3 /h (0.02 kt/year) were detected, indicating that AVIRIS-NG has the capability of detecting a wide range of fugitive CH 4 source categories for natural gas fields. This controlled release experiment is the first of its kind using AVIRIS-NG and demonstrates the utility of imaging spectrometers for direct attribution of emissions to individual point source locations. This is particularly useful given the large uncertainties associated with anthropogenic CH 4 emissions, including those from industry, gas transmission lines, and the oil and gas sectors.

We introduce a retrieval algorithm to estimate lower tropospheric methane (CH4) concentrations from the surface to 1 km with uncertainty estimates using Hyperspectral Thermal Emission Spectrometer (HyTES) airborne radiance measurements. After resampling, retrievals have a spatial resolution of 6 × 6 m2. The total error from a single retrieval is approximately 20 %, with the uncertainties determined primarily by noise and spectral interferences from air temperature, surface emissivity, and atmospheric water vapor. We demonstrate retrievals for a HyTES flight line over storage tanks near Kern River Oil Field (KROF), Kern County, California, and find an extended plume structure in the set of observations with elevated methane concentrations (3.0 ± 0.6 to 6.0 ± 1.2 ppm), well above mean concentrations (1.8 ± 0.4 ppm) observed for this scene. With typically a 20 % estimated uncertainty, plume enhancements with more than 1 ppm are distinguishable from the background values with its uncertainty. HyTES retrievals are consistent with simultaneous airborne and ground-based in situ CH4 mole fraction measurements within the reported accuracy of approximately 0.2 ppm (or ∼ 8 %), due to retrieval interferences related to air temperature, emissivity, and H2O.

The Airborne Methane Plume Spectrometer (AMPS) is a mature instrument concept that is ready for development at the Jet Propulsion Laboratory (JPL). At its core is a novel high-resolution imaging spectrometer that records solar reflected light between 1.99 and 2.42 pm at 1 nm resolution, including strong methane (CH4) bands in the short-wave infrared. The push-broom spectrometer will leverage recent advancements in grating design and large-format 2D focal plane arrays to enable — for the first time — the high spectral resolution necessary for trace gas retrievals combined with high-performance imaging capabilities developed for surface remote sensing. AMPS features a 36° field of view with 600 resolved spatial elements across track (1 mRad) and 431 pixels in the spectral dimension. All other aspects of the instrument, such as the telescope, cryo-cooler, image stabilizer, GPS, are identical to available airborne JPL spectrometers in operation. The AMPS design is based on the next generation Airborne Visible Infrared Imaging Spectrometer (AVIRIS-NG), which has been used for high resolution mapping of CH4 concentrations from a controlled release experiment [1] and over existing natural gas fields [2]. A real time CH4 plume detection capability originally developed for AVIRIS-NG and successfully demonstrated over oil fields [3] will also be implemented with AMPS. This will facilitate surveys over existing oil and gas fields to identify and attribute CH4 emissions to individual point source locations, permit adaptive surveys with repeat imaging of suspected sources, and allow real time communication to site operators or ground crews equipped with additional instruments to verify observed plumes. AMPS will enable quantitative imaging of CH4 plumes at unprecedented spatial resolution and precision. Using a slow moving platform such as a helicopter at 100 m flight altitude (60 m image swath) will permit imaging CH4 enhancements at 10 cm spatial resolution and an unprecedented accuracy of 0.05 g CH4/m2. This will allow robust detection of CH4 emissions as low as 0.17 m3/h (6 standard cubic feet per hour), an order of magnitude smaller than what current airborne systems can detect. Using fixed-wing aircraft, AMPS can also be flown faster and higher (1 to 8 km flight altitude), thereby providing larger image swaths (0.6 to 4.8 km swaths respectively) and effective large scale surveys. Mapping CH4 emissions to individual point source locations could allow site operators to identify and mitigate these emissions, which reflect both a potential safety hazard and lost revenue. For the regulatory and scientific communities, understanding the distribution (spatial, temporal) and size of these emissions is of interest given the large uncertainties associated with anthropogenic emissions, including industrial point source emissions and fugitive CH4 from oil and gas infrastructure.

Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1–2 km), and high spatial resolution (∼ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

Despite being plagued by heavily degraded DNA in palaeontological remains, most studies addressing the state of DNA degradation have been limited to types of damage which do not pose a hindrance to Taq polymerase during PCR. Application of serial qPCR to the two fractions obtained during extraction (demineralization and protein digest) from six permafrost mammoth bones and one partially degraded modern elephant bone has enabled further insight into the changes which endogenous DNA is subjected to during diagenesis. We show here that both fractions exhibit individual qualities in terms of the prevailing type of DNA (i.e. mitochondrial versus nuclear DNA) as well as the extent of damage, and in addition observed a highly variable ratio of mitochondrial to nuclear DNA among the six mammoth samples. While there is evidence suggesting that mitochondrial DNA is better preserved than nuclear DNA in ancient permafrost samples, we find the initial DNA concentration in the bone tissue to be as relevant for the total accessible mitochondrial DNA as the extent of DNA degradation post-mortem. We also evaluate the general applicability of indirect measures of preservation such as amino-acid racemization, bone crystallinity index and thermal age to these exceptionally well-preserved samples.

Airborne imaging spectroscopy has evolved dramatically since the 1980s as a robust remote sensing technique used to generate 2-dimensional maps of surface properties over large spatial areas. Traditional applications for passive airborne imaging spectroscopy include interrogation of surface composition, such as mapping of vegetation diversity and surface geological composition. Two recent applications are particularly relevant to the needs of both the oil and gas as well as government sectors: quantification of surficial hydrocarbon thickness in aquatic environments and mapping atmospheric greenhouse gas components. These techniques provide valuable capabilities for petroleum seepage in addition to detection and quantification of fugitive emissions. New empirical data that provides insight into the source strength of anthropogenic methane will be reviewed, with particular emphasis on the evolving constraints enabled by new methane remote sensing techniques. Contemporary studies attribute high-strength point sources as significantly contributing to the national methane inventory and underscore the need for high performance remote sensing technologies that provide quantitative leak detection. Imaging sensors that map spatial distributions of methane anomalies provide effective techniques to detect, localize, and quantify fugitive leaks. Airborne remote sensing instruments provide the unique combination of high spatial resolution (< 1 m) and large coverage required to directly attribute methane emissions to individual emission sources. This capability cannot currently be achieved using spaceborne sensors. In this study, results from recent NASA remote sensing field experiments focused on point-source leak detection, will be highlighted. This includes existing quantitative capabilities for oil and methane using state-of-the-art airborne remote sensing instruments. While these capabilities are of interest to NASA for assessment of environmental impact and global climate change, industry similarly seeks to detect and localize leaks of both oil and methane across operating fields. In some cases, higher sensitivities desired for upstream and downstream applications can only be provided by new airborne remote sensing instruments tailored specifically for a given application. There exists a unique opportunity for alignment of efforts between commercial and government sectors to advance the next generation of instruments to provide more sensitive leak detection capabilities, including those for quantitative source strength determination.

International audience; We have developed a sublimation technique coupled with chemical derivatization and gas chromatography mass spectrometry (GC-MS) to detect nucleobases and other volatile organic compounds derived from bacteria in Mars analog materials. To demonstrate this technique, a sample of serpentine inoculated with Escherichia coli (E coli) cells was heated to 500 degrees C for several seconds under Martian ambient pressure. The sublimate was collected on a cold finger, then derivatized and analyzed by GC-MS. We found that adenine, cytosine, thymine and uracil were the most abundant molecules detected in the sublimed E coli extract by GC-MS. In addition, nucleobases were also detected in sublimed extracts of a deep-sea sediment sample, seawater, and soil collected from the Atacama Desert in Chile after heating the samples under the same conditions. Our results indicate that nucleobases can be easily isolated directly from natural samples using sublimation and then detected by GC-MS after chemical derivatization. The sublimation-based extraction technique is one approach that should be considered for use by future in situ instruments designed to detect organic compounds relevant to life in the Martian regolith.

Amino acid analyses of the Antarctic CM2 chondrites Allan Hills (ALH) 83100 and Lewis Cliff (LEW) 90500 using liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS) coupled with UV fluorescence detection revealed that these carbonaceous meteorites contain a suite of indigenous amino acids not present in Antarctic ice. Several amino acids were detected in ALH 83100, including glycine, alanine, β-alanine, γ-amino-n-butyric acid (γ-ABA), and α- aminoisobutyric acid (AIB) with concentrations ranging from 250 to 340 parts per billion (ppb). In contrast to ALH 83100, the CM2 meteorites LEW 90500 and Murchison had a much higher total abundance of these amino acids (440-3200 ppb). In addition, ALH 83100 was found to have lower abundances of the α-dialkyl amino acids AIB and isovaline than LEW 90500 and Murchison. There are three possible explanations for the depleted amino acid content in ALH 83100: 1) amino acid leaching from ALH 83100 during exposure to Antarctic ice meltwater, 2) a higher degree of aqueous alteration on the ALH 83100 parent body, or 3) ALH 83100 originated on a chemically distinct parent body from the other two CM2 meteorites. The high relative abundance of e-amino-n-caproic acid (EACA) in the ALH 83100 meteorite as well as the Antarctic ice indicates that Nylon-6 contamination from the Antarctic sample storage bags may have occurred during collection.

The Mars Organic Analyzer (MOA), a microfabricated capillary electrophoresis (CE) instrument for sensitive amino acid biomarker analysis, has been developed and evaluated. The microdevice consists of a four-wafer sandwich combining glass CE separation channels, microfabricated pneumatic membrane valves and pumps, and a nanoliter fluidic network. The portable MOA instrument integrates high voltage CE power supplies, pneumatic controls, and fluorescence detection optics necessary for field operation. The amino acid concentration sensitivities range from micromolar to 0.1 nM, corresponding to part-per-trillion sensitivity. The MOA was first used in the lab to analyze soil extracts from the Atacama Desert, Chile, detecting amino acids ranging from 10–600 parts per billion. Field tests of the MOA in the Panoche Valley, CA, successfully detected amino acids at 70 parts per trillion to 100 parts per billion in jarosite, a sulfate-rich mineral associated with liquid water that was recently detected on Mars. These results demonstrate the feasibility of using the MOA to perform sensitive in situ amino acid biomarker analysis on soil samples representative of a Mars-like environment.

The successes of the Mars exploration program have led to our unprecedented knowledge of the geological, mineralogical, and elemental composition of the martian surface. To date, however, only one mission, the Phoenix lander, has specifically set out to determine the soluble chemistry of the martian surface. The surprising results, including the detection of perchlorate, demonstrated both the importance of performing soluble ion measurements and the need for improved instrumentation to unambiguously identify all the species present. Ion chromatography (IC) is the state-of-the-art technique for soluble ion analysis on Earth and would therefore be the ideal instrument to send to Mars. A flight IC system must necessarily be small, lightweight, low-power, and have low eluent consumption. We demonstrate here a breadboard system that addresses these issues by using capillary IC at low flow rates with an optimized eluent generator and suppressor. A mix of 12 ions known or plausible for the martian soil, including 4 (oxy)chlorine species, has been separated at flow rates ranging from 1 to 10 μL/min, requiring as little as 200 psi at 1.0 μL/min. This allowed the use of pneumatic displacement pumping from a pressurized aluminum eluent reservoir and the elimination of the high-pressure pump entirely (the single heaviest and most energy-intensive component). All ions could be separated and detected effectively from 0.5 to 100 μM, even when millimolar concentrations of perchlorate were present in the same mixtures.

H 2 O, CO 2 , SO 2 , O 2 , H 2 , H 2 S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H 2 O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO 2 . Concurrent evolution of O 2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.

Previous studies of the subsurface biosphere have deduced average cellular doubling times of hundreds to thousands of years based upon geochemical models. We have directly constrained the in situ average cellular protein turnover or doubling times for metabolically active micro-organisms based on cellular amino acid abundances, D/L values of cellular aspartic acid, and the in vivo aspartic acid racemization rate. Application of this method to planktonic microbial communities collected from deep fractures in South Africa yielded maximum cellular amino acid turnover times of ~89 years for 1 km depth and 27 °C and 1–2 years for 3 km depth and 54 °C. The latter turnover times are much shorter than previously estimated cellular turnover times based upon geochemical arguments. The aspartic acid racemization rate at higher temperatures yields cellular protein doubling times that are consistent with the survival times of hyperthermophilic strains and predicts that at temperatures of 85 °C, cells must replace proteins every couple of days to maintain enzymatic activity. Such a high maintenance requirement may be the principal limit on the abundance of living micro-organisms in the deep, hot subsurface biosphere, as well as a potential limit on their activity. The measurement of the D/L of aspartic acid in biological samples is a potentially powerful tool for deep, fractured continental and oceanic crustal settings where geochemical models of carbon turnover times are poorly constrained. Experimental observations on the racemization rates of aspartic acid in living thermophiles and hyperthermophiles could test this hypothesis. The development of corrections for cell wall peptides and spores will be required, however, to improve the accuracy of these estimates for environmental samples.

Abstract The Jet Propulsion Laboratory (JPL) routinely operates robotic spacecraftmillions of miles from the Earth. Current JPL missions include roving on Marsand observing the Sun, Earth, Saturn, comets and asteroids and deep space. Advances in high-fidelity modeling, simulation and visualization, high-precision sensors, instruments, harsh-environment electronics, autonomousoperations and on-board intelligence have enabled these challenging missions. Robotics capabilities developed at JPL have been applied to the MarsPathfinder, Mars Exploration Rover, Deep Space 1, EOS1 and other space missionsand used on many JPL research projects conducted for NASA, the US Department ofDefense and private industry. Although developed for space applications, thesetechnologies are also highly relevant to problems in terrestrial oil and gasexploration and production. Benefits from the deployment of these technologiesinclude greater precision, increased reliability, reduced uncertainty, increased productivity, reduced cost, and accelerated development schedules andtask completion times. In this paper, we provide a description of some of thesetechnologies and suggest how they might benefit the oil and gas industry Introduction JPL is a United States federally funded research and development center managedby the California Institute of Technology under a contract with NASA. Foundedmore than 50 years ago, JPL has been responsible for many pioneering spaceachievements including building and controlling Explorer 1 - the first USsatellite, the Ranger and Surveyor missions to land on the moon, Mariner 2 -the first spacecraft to Venus, the Viking missions to land on Mars, Voyager 1and 2 - the spacecraft that toured Jupiter, Saturn, Uranus and Neptune, theMars Pathfinder and Mars Exploration Rovers to drive on Mars and many others toobserve the planets, the sun, comets, and asteroids. In addition to itsplanetary exploration mission, JPL is actively involved in Earth science. Instruments and Earth-orbiting satellites developed at JPL study the geology, hydrology, ecology, oceanography, gravity and climate of the Earth. JPL alsoconducts missions focused beyond our solar system. Observations of deep spacehave yielded information about galaxy, star and planetary system formation, developed maps of our Milky Way galaxy and the universe, and found planets onother star systems. To enable these missions, JPL continues to developtechnologies in telecommunications, navigation, intelligent automation, imagingand image analyses, robotics, science instruments and micro- and nano-systems. In telecommunications, for example, JPL is able to collect data from theVoyager spacecraft beaming a 23 Watt signal from the edge of our solar systemmore than 14 billion kilometers away. There are a number of similarities between space applications and applicationsin the oil & gas industry (Oxnevad, 2010). In both cases, systems aredeployed at remote locations with limited access for intervention, maintenanceor repair. The operational environments are often hostile with harshtemperatures and pressures and corrosive materials. Reliability of systems isextremely important in space and in the oil and gas industry. Operations in therespective environments have high risk and the capabilities for replicatingenvironmental conditions for testing and failure mitigation are limited. Failures can be catastrophic and the cost, financially and in publicperception, can erode support for programs. Due to these similarities, there ismuch that the space and energy sectors can learn and benefit from eachother.

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H 2 S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H 2 S, CH 4 , NH 3 , and CO 2 . A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H 2 S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H 2 S may have played an important role in prebiotic reactions in early solar system environments.

It has been proposed that oligopeptides may be formed in submarine hydrothermal systems (SHSs). Oligopeptides have been synthesized previously under simulated SHS conditions which are likely geochemically implausible. We have herein investigated the oligomerization of glycine under SHS-like conditions with respect to the limitations imposed by starting amino acid concentration, heating time, and temperature. When 10(-1) M glycine solutions were heated at 250 degrees C for20 min glycine oligomers up to tetramers and diketopiperazine (DKP) were detectable. At 200 degrees C, less oligomerization was noted. Peptides beyond glycylglycine (gly2) and DKP were not detected below 150 degrees C. At 10(-2) M initial glycine concentration and below, only gly2, DKP, and gly3 were detected, and then only above 200 degrees C at20 min reaction time. Gly3 was undetectable at longer reaction times. The major parameters limiting peptide synthesis in SHSs appear to be concentration, time, and temperature. Given the expected low concentrations of amino acids, the long residence times and range of temperatures in SHSs, it is unlikely that SHS environments were robust sources of even simple peptides. Possible unexplored solutions to the problems presented here are also discussed.

There is little consensus regarding the plausibility of organic synthesis in submarine hydrothermal systems (SHSs) and its possible relevance to the origin of life. The primary reason for the persistence of this debate is that most experimental high temperature and high-pressure organic synthesis studies have neglected important geochemical constraints with respect to source material composition. We report here the results of experiments exploring the potential for amino acid synthesis at high temperature from synthetic seawater solutions of varying composition. The synthesis of amino acids was examined as a function of temperature, heating time, starting material composition and concentration. Using very favorable reactant conditions (high concentrations of reactive, reduced species), small amounts of a limited set of amino acids are generated at moderate temperature conditions ( approximately 125-175 degrees C) over short heating times of a few days, but even these products are significantly decomposed after exposure times of approximately 1 week. The high concentration dependence observed for these synthetic reactions are demonstrated by the fact that a 10-fold drop in concentration results in orders of magnitude lower yields of amino acids. There may be other synthetic mechanisms not studied herein that merit investigation, but the results are likely to be similar. We conclude that although amino acids can be generated from simple likely environmentally available precursors under SHS conditions, the equilibrium at high temperatures characteristic of SHSs favors net amino acid degradation rather than synthesis, and that synthesis at lower temperatures may be more favorable.

The Urey organic and oxidant detector consists of a suite of instruments designed to search for several classes of organic molecules in the martian regolith and ascertain whether these compounds were produced by biotic or abiotic processes using chirality measurements. These experiments will also determine the chemical stability of organic molecules within the host regolith based on the presence and chemical reactivity of surface and atmospheric oxidants. Urey has been selected for the Pasteur payload on the European Space Agency's (ESA's) upcoming 2013 ExoMars rover mission. The diverse and effective capabilities of Urey make it an integral part of the payload and will help to achieve a large portion of the mission's primary scientific objective: “to search for signs of past and present life on Mars.” This instrument is named in honor of Harold Urey for his seminal contributions to the fields of cosmochemistry and the origin of life.

[1] The Urey in situ organic compound analysis instrument, consisting of a subcritical water extractor (SCWE) and a portable microchip capillary electrophoresis instrument called the Mars Organic Analyzer (MOA), was field tested in the Atacama Desert, Chile, in June 2005. Soil samples from the most arid Yungay region were collected, biomarkers were extracted by the SCWE, and organic amine composition and amino acid chirality analysis was performed by the MOA. Samples collected from the top 1 cm of duracrust soil but shielded from the ambient environment by rocks were compared to the exposed duracrust. The shielded duracrust yielded amines and amino acids ranging from 50 to 100 ppb, while amino acid signals from the exposed duracrust were below blank levels. Samples from buried gypsum deposits located directly above a water flow channel contained amino acids ranging from 13 to 90 ppb. Chiral analysis revealed D/L ratios of 0.39 ± 0.08 and 0.34 ± 0.07 for alanine/serine and 0.78 ± 0.06 for aspartic acid, indicating significant racemization of biologically produced amino acids. On the basis of the D/L ratios, we estimate sample ages ranging from 103 to 105 years. These results demonstrate the successful field testing of the Urey instrument, as well as the detection of biomarkers from past terrestrial life in one of the most arid and Mars-like regions on Earth.

Strong evidence for evaporitic sulfate minerals such as gypsum and jarosite has recently been found on Mars. Although organic molecules are often codeposited with terrestrial evaporitic minerals, there have been no systematic investigations of organic components in sulfate minerals. We report here the detection of organic material, including amino acids and their amine degradation products, in ancient terrestrial sulfate minerals. Amino acids and amines appear to be preserved for geologically long periods in sulfate mineral matrices. This suggests that sulfate minerals should be prime targets in the search for organic compounds, including those of biological origin, on Mars.