Method for Accurate Detection of Amino Acids and Mycotoxins in Planetary Atmospheres

We present a systematic analysis of a large number of mass spectra accumulated as the number of ion fragments recorded in unit mass-to-charge detector channels. The method retrieves the abundances of detected species using an efficient deconvolution algorithm, which relies on fragment pattern recognition, mass calibration, and background correction. The abundance analysis identifies target species, amino acids, and mycotoxins through their characteristic fragmentation patterns in the presence of an increasing number of interfering species. The method offered robust and efficient retrieval of abundances of metabolic molecules in complex mixtures obscured by a wide range of toxic compounds.

Viruses in astrobiology

Viruses are the most abundant biological entities on Earth, and yet, they have not received enough consideration in astrobiology. Viruses are also extraordinarily diverse, which is evident in the types of relationships they establish with their host, their strategies to store and replicate their genetic information and the enormous diversity of genes they contain. A viral population, especially if it corresponds to a virus with an RNA genome, can contain an array of sequence variants that greatly exceeds what is present in most cell populations. The fact that viruses always need cellular resources to multiply means that they establish very close interactions with cells. Although in the short term these relationships may appear to be negative for life, it is evident that they can be beneficial in the long term. Viruses are one of the most powerful selective pressures that exist, accelerating the evolution of defense mechanisms in the cellular world. They can also exchange genetic material with the host during the infection process, providing organisms with capacities that favor the colonization of new ecological niches or confer an advantage over competitors, just to cite a few examples. In addition, viruses have a relevant participation in the biogeochemical cycles of our planet, contributing to the recycling of the matter necessary for the maintenance of life. Therefore, although viruses have traditionally been excluded from the tree of life, the structure of this tree is largely the result of the interactions that have been established throughout the intertwined history of the cellular and the viral worlds. We do not know how other possible biospheres outside our planet could be, but it is clear that viruses play an essential role in the terrestrial one. Therefore, they must be taken into account both to improve our understanding of life that we know, and to understand other possible lives that might exist in the cosmos.

IN SITU MASS SPECTROMETERS FOR APPLICATIONS IN SPACE

Mass spectrometry (MS) has played a remarkable role in exploring the chemical make-up of our solar system. In situ probes were historically developed to analyze inorganic/elemental compositions while leveraging native ions or harsh ionization methods to aid in exploring astrophysics applications (e.g., heliophysics). The part played by MS is demonstrated in a majority of scientific payloads focused on exploration, particularly at the turn of the century with missions including Cassini-Huygens, Rosetta, and now Mars Science Laboratory. Plasma mass spectrometers have grown more sophisticated to interrogate fundamental inorganic analysis (e.g., solar wind and magnetospheres) including both native ions and neutrals. Cosmic dust floating in-between and orbiting planetary bodies has been targeted by unique sampling via impact ionization. More complex systems rely on landed planetary instrumentation with lessons learned from pioneering missions in the 1970s and 1980s to near neighbors Mars and Venus. Modern probes have expanded applicable target chemicals by recognizing the needs to provide for molecular analyses, extended mass range, and high resolution to provide unequivocal detection and identification. Notably, as the field surrounding astrobiology has gained momentum, so has the in situ detection of complex molecular chemistry including the chemical evolution of organic molecules. Mission context often includes long term timelines from spacecraft launch to arrival and additionally the diverse target environments across various planets. Therefore, customized experimental designs for space MS have been born of necessity. To this point, the development of MS instrumentation on Earth has now far outpaced development for experiments in space. Therefore, exciting developments lie ahead among various international space agencies conducting current and future mission planning with increasingly enhanced instrumentation. For instance, near-neighbor Mars has entertained considerable attention with complex MS instrumentation with laser desorption ionization aboard the Mars Organic Molecule Analyzer instrument. To study comets, the Rosetta mission employs a secondary ionization mechanism. Meanwhile, the various moons of Jupiter and Saturn have intriguing surface and subsurface properties that warrant more advanced analyzer systems. Instrumentation design will continue to evolve as requirements develop and this review serves as a reflection of the contribution of in situ MS to space exploration in the past 20 years and the anticipated contribution yet to come. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Analytical Chemistry in Astrobiology

This Feature introduces and discusses the findings of key analytical techniques used to study planetary bodies in our solar system in the search for life beyond Earth, future missions planned for high-priority astrobiology targets in our solar system, and the challenges we face in performing these investigations.

Water on Mars—A Literature Review

To assess Mars’ potential for both harboring life and providing useable resources for future human exploration, it is of paramount importance to comprehend the water situation on the planet. Therefore, studies have been conducted to determine any evidence of past or present water existence on Mars. While the presence of abundant water on Mars very early in its history is widely accepted, on its modern form, only a fraction of this water can be found, as either ice or locked into the structure of Mars’ plentiful water-rich materials. Water on the planet is evaluated through various evidence such as rocks and minerals, Martian achondrites, low volume transient briny outflows (e.g., dune flows, reactivated gullies, slope streaks, etc.), diurnal shallow soil moisture (e.g., measurements by Curiosity and Phoenix Lander), geomorphic representation (possibly from lakes and river valleys), and groundwater, along with further evidence obtained by probe and rover discoveries. One of the most significant lines of evidence is for an ancient streambed in Gale Crater, implying ancient amounts of “vigorous” water on Mars. Long ago, hospitable conditions for microbial life existed on the surface of Mars, as it was likely periodically wet. However, its current dry surface makes it almost impossible as an appropriate environment for living organisms; therefore, scientists have recognized the planet’s subsurface environments as the best potential locations for exploring life on Mars. As a result, modern research has aimed towards discovering underground water, leading to the discovery of a large amount of underground ice in 2016 by NASA, and a subglacial lake in 2018 by Italian scientists. Nevertheless, the presence of life in Mars’ history is still an open question. In this unifying context, the current review summarizes results from a wide variety of studies and reports related to the history of water on Mars, as well as any related discussions on the possibility of living organism existence on the planet.

Relative Humidity on Mars: New Results From the Phoenix TECP Sensor

In situ measurements of relative humidity (RH) on Mars have only been performed by the Phoenix (PHX) and Mars Science Laboratory (MSL) missions. Here we present results of our recalibration of the PHX thermal and electrical conductivity probe (TECP) RH sensor. This recalibration was conducted using a TECP engineering model subjected to the full range of environmental conditions at the PHX landing site in the Michigan Mars Environmental Chamber. The experiments focused on the warmest and driest conditions (daytime) because they were not covered in the original calibration (Zent et al., 2010, https://doi.org/10.1029/2009JE003420) and previous recalibration (Zent et al., 2016, https://doi.org/10.1002/2015JE004933). In nighttime conditions, our results are in excellent agreement with the previous 2016 recalibration, while in daytime conditions, our results show larger water vapor pressure values. We obtain vapor pressure values in the range ~0.005-1.4 Pa, while Zent et al. (2016, https://doi.org/10.1002/2015JE004933) obtain values in the range ~0.004-0.4 Pa. Our higher daytime values are in better agreement with independent estimates from the ground by the PHX Surface Stereo Imager instrument and from orbit by Compact Reconnaissance Imaging Spectrometer for Mars. Our results imply larger day-to-night ratios of water vapor pressure at PHX compared to MSL, suggesting a stronger atmosphere-regolith interchange in the Martian arctic than at lower latitudes. Further, they indicate that brine formation at the PHX landing site via deliquescence can be achieved only temporarily between midnight and 6 a.m. on a few sols. The results from our recalibration are important because they shed light on the near-surface humidity environment on Mars.

Developing Intra-EVA Science Support Team Practices for a Human Mission to Mars

During the BASALT research program, real (nonsimulated) geological and biological science was accomplished through a series of extravehicular activities (EVAs) under simulated Mars mission conditions. These EVAs were supported by a Mission Support Center (MSC) that included an on-site, colocated Science Support Team (SST). The SST was composed of scientists from a variety of disciplines and operations researchers who provided scientific and technical expertise to the crew while each EVA was being conducted (intra-EVA). SST management and organization developed under operational conditions that included Mars-like communication latencies, bandwidth constraints, and EVA plans that were infused with Mars analog field science objectives. This paper focuses on the SST workspace considerations such as science team roles, physical layout, communication interactions, operational techniques, and work support technology. Over the course of BASALT field deployments to Idaho and Hawai'i, the SST team made several changes of note to increase both productivity and efficiency. For example, new roles were added for more effective management of technical discussions, and the layout of the SST workspace evolved multiple times during the deployments. SST members' reflexive adjustments resulted in a layout that prioritized face-to-face discussions over face-to-data displays, highlighting the importance of interpersonal communication during SST decision-making. In tandem with these workspace adjustments, a range of operational techniques were developed to help the SST manage discussions and information flow under time pressure.

Solving for ambiguities in radar geophysical exploration of planetary bodies by mimicking bats echolocation

Sounders are spaceborne radars which are widely employed for geophysical exploration of celestial bodies around the solar system. They provide unique information regarding the subsurface structure and composition of planets and their moons. The acquired data are often affected by unwanted artifacts, which hinder the data interpretation conducted by geophysicists. Bats possess a remarkable ability in discriminating between a prey, such as a quick-moving insect, and unwanted clutter (e.g., foliage) by effectively employing their bio-sonar perfected in million years of evolution. Striking analogies occur between the characteristics of bats sonar and the one of a radar sounder. Here we propose an adaptation of the unique bat clutter discrimination capability to radar sounding by devising a novel clutter detection model. The proposed bio-inspired strategy proves its effectiveness on Mars experimental data and paves the way for a new generation of sounders which eases the data interpretation by planetary scientists.

Radar sounders, used for the geophysical exploration of celestial objects in the solar system, possess striking similarities to bat sonars. Here, the authors adapt and implement the bat clutter mitigation mechanism to radar geophysical exploration of planetary bodies.

Autonomy for ground-level robotic space exploration: framework, simulation, architecture, algorithms and experiments

Robotic surface planetary exploration is a challenging endeavor, with critical safety requirements and severe communication constraints. Autonomous navigation is one of the most crucial and yet risky aspects of these operations. Therefore, a certain level of local autonomy for onboard robots is an essential feature, so that they can make their own decisions independently of ground control, reducing operational costs and maximizing the scientific return of the mission. In addition, existing tools to support research in this domain are usually proprietary to space agencies, and out of reach of most researchers. This paper presents a framework developed to support research in this field, a modular onboard software architecture design and a series of algorithms that implement a visual-based autonomous navigation approach for robotic space exploration. It allows analysis of algorithms' performance and functional validation of approaches and autonomy strategies, data monitoring and the creation of simulation models to replicate the vehicle, sensors, terrain and operational conditions. The framework and algorithms are partly supported by open-source packages and tools. A set of experiments and field testing with a physical robot and hardware are described as well, detailing results and algorithms' processing time, which experience an incremented of one order of magnitude when executed in space-certified like hardware, with constrained resources, in comparison to using general purpose hardware.

Rb-Sr resonance ionization geochronology of the Duluth Gabbro: A proof of concept for in situ dating on the Moon

RATIONALE

We report new (87) Rb-(87) Sr isochron data for the Duluth Gabbro, obtained with a laser ablation resonance ionization mass spectrometer that is a prototype spaceflight instrument. The gabbro has a Rb abundance and a range of Rb/Sr ratios that are similar to those of KREEP-rich basalts found on the nearside of the Moon. Dating of previously un-sampled young lunar basalts, which generally have a KREEP-rich composition, is critical for understanding the bombardment history of the Moon since 3.5 Ga, which in turn informs the chronology of the solar system. Measurements of lunar analogs like the Duluth Gabbro are a proof of concept for in situ dating of rocks on the Moon to constrain lunar history.

METHODS

Using the laser ablation resonance ionization mass spectrometer we ablated hundreds of locations on a sample, and at each one measured the relative abundances of the isotopes of Rb and Sr. A delay between the resonant photoionization processes separates the elements in time, eliminating the potential interference between (87) Rb and (87) Sr. This enables the determination of (87) Rb-(87) Sr isochron ages without sophisticated sample preparation that would be impractical in a spaceflight context.

RESULTS

We successfully dated the Duluth Gabbro to 800 ± 300 Ma using traditional isochron methods like those used in our earlier analysis of the Martian meteorite Zagami. However, we were able to improve this to 1100 ± 200 Ma, an accuracy of <1σ, using a novel normalization approach. Both these results agree with the age determined by Faure et al. in 1969, but our novel normalization improves our precision.

CONCLUSIONS

Demonstrating that this technique can be used for measurements at this level of difficulty makes ~32% of the lunar nearside amenable to in situ dating, which can complement or supplement a sample return program. Given these results and the scientific value of dating young lunar basalts, we have recently proposed a spaceflight mission called the Moon Age and Regolith Explorer (MARE).

Science applications of a multispectral microscopic imager for the astrobiological exploration of Mars

Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples most likely to harbor fossil biosignatures. The Multispectral Microscopic Imager (MMI) provides multispectral reflectance images of geological samples at the microscale, where each image pixel is composed of a visible/shortwave infrared spectrum ranging from 0.46 to 1.73 μm. This spectral range enables the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases, and the detection of hydrated minerals. The MMI advances beyond the capabilities of current microimagers on Mars by extending the spectral range into the infrared and increasing the number of spectral bands. The design employs multispectral light-emitting diodes and an uncooled indium gallium arsenide focal plane array to achieve a very low mass and high reliability. To better understand and demonstrate the capabilities of the MMI for future surface missions to Mars, we analyzed samples from Mars-relevant analog environments with the MMI. Results indicate that the MMI images faithfully resolve the fine-scale microtextural features of samples and provide important information to help constrain mineral composition. The use of spectral endmember mapping reveals the distribution of Fe-bearing minerals (including silicates and oxides) with high fidelity, along with the presence of hydrated minerals. MMI-based petrogenetic interpretations compare favorably with laboratory-based analyses, revealing the value of the MMI for future in situ rover-mediated astrobiological exploration of Mars.

Organics on Mars?

Organics are expected to exist on Mars based on meteorite infall, in situ production, and any possible biological sources. Yet they have not been detected on the martian surface; are they there, or are we not capable enough to detect them? The Viking gas chromatograph-mass spectrometer did not detect organics in the headspace of heated soil samples with a detection limit of parts per billion. This null result strongly influenced the interpretation of the reactivity seen in the Viking biology experiments and led to the conclusion that life was not present and, instead, that there was some chemical reactivity in the soil. The detection of perchlorates in the martian soil by instruments on the Phoenix lander and the reports of methane in the martian atmosphere suggest that it may be time to reconsider the question of organics. The high-temperature oxidizing properties of perchlorate will promote combustion of organics in pyrolytic experiments and may have affected the ability of both Phoenix's organic analysis experiment and the Viking mass spectrometer experiments to detect organics. So the question of organics on Mars remains open. A primary focus of the upcoming Mars Science Laboratory will be the detection and identification of organic molecules by means of thermal volatilization, followed by gas chromatography-mass spectrometry--as was done on Viking. However, to enhance organic detectability, some of the samples will be processed with liquid derivatization agents that will dissolve organics from the soil before pyrolysis, which may separate them from the soil perchlorates. Nonetheless, the problem of organics on Mars is not solved, and for future missions other organic detection techniques should therefore be considered as well.

Intracoronary shunt in off-pump coronary artery bypass graft

This study was performed to compare the early postoperative results of off Pump Coronary Artery Bypass Graft (OPCABG) with or without using Intra Coronary Shunt (ICS). We randomized 208 patients scheduled for OPCABG into shunt group (group 1, n = 104) and no-shunt group (group 2, n = 104). The two groups were well matched according to the age, gender, angina class, New York Heart Association (NYHA) functional class, or operative priority and disease severity. Peri- and post-operative changes in electrocardiography, wall motion abnormality in echocardiography, rate of myocardial infarction, mortality, morbidity, cardiac enzymes and ICU stay were recorded. There was no significant difference between two groups in changes of electrocardiography, myocardial infarction, left ventricular ejection fraction (LVEF), in hospital mortality and ICU stay but Creatine Kinase Myocardial Band (CK-MB) enzyme was higher in no shunt group, while troponin-I was increased in shunt group. Preoperative LVEF was higher in no-shunt group, but postoperative LVEF was higher in shunt group (p > 0.05). Also, the change of LVEF before and after operation in each group was not significant. Using intracoronary shunt in off pump coronary artery bypass graft leads to less change in cardiac enzymes but had no effect on perioperative and postoperative myocardial infarction, LVEF, mortality and morbidity.

H2O at the Phoenix landing site

The Phoenix mission investigated patterned ground and weather in the northern arctic region of Mars for 5 months starting 25 May 2008 (solar longitude between 76.5 degrees and 148 degrees ). A shallow ice table was uncovered by the robotic arm in the center and edge of a nearby polygon at depths of 5 to 18 centimeters. In late summer, snowfall and frost blanketed the surface at night; H(2)O ice and vapor constantly interacted with the soil. The soil was alkaline (pH = 7.7) and contained CaCO(3), aqueous minerals, and salts up to several weight percent in the indurated surface soil. Their formation likely required the presence of water.