Field and laboratory validation of remote rover operations Science Team findings: The CanMars Mars Sample Return analogue mission

The CanMars Mars Sample Return Analogue Deployment (MSRAD) was a closely simulated, end-to-end Mars Sample Return (MSR) mission scenario, with instrumentation, goals, and constraints modeled on the upcoming NASA Mars 2020 rover mission; this paper reports on the post-mission validation of the exercise. The exercise utilized the CSA Mars Exploration Science Rover (MESR) rover, deployed to Utah, USA, at a Mars-analogue field site. The principal features of the field site located near Green River, Utah are Late Jurassic inverted, fluvial paleochannels, analogous to features on Mars in sites being considered for the ESA ExoMars rover mission and present within the chosen landing site for the Mars 2020 rover mission. The in-simulation (“in-sim”) mission operations team worked remotely from The University of Western Ontario, Canada. A suite of MESR-integrated and hand-held spectrometers was selected to mimic those of the Mars 2020 payload, and a Utah-based, on-site team was tasked with field operations to carry out the data collection and sampling as commanded by the in-sim team. As a validation of the in-sim mission science findings, the field team performed an independent geological assessment. This paper documents the field team's on-site geological assessment and subsequent laboratory and analytical results, then offers a comparison of mission (in-sim) and post-mission (laboratory) science results. The laboratory-based findings were largely consistent with the in-sim rover-derived data and geological interpretations, though some notable exceptions highlight the inherent difficulties in remote science. In some cases, available data was insufficient for lithologic identification given the absence of other important contextual information (e.g., textural information). This study suggests that the in-sim instruments were largely adequate for the Science Team to characterize samples; however, rover-based field work is necessarily hampered by mobility and time constraints with an obvious effect on efficiency but also precision, and to some extent, accuracy of the findings. The data show a dearth of preserved total organic carbon (TOC) – used as a proxy for ancient biosignature preservation potential – in the fluvial-lacustrine system of this field site, suggesting serious consideration with respect to the capabilities and opportunities for addressing the Mars exploration goals. We therefore suggest a thorough characterization of terrestrial sites analogous to those of Mars rover landing sites, and in-depth field studies like CanMars as important, pre-mission strategic exercises

Field and laboratory validation of remote rover operations Science Team findings: The CanMars Mars Sample Return analogue mission

The CanMars Mars Sample Return Analogue Deployment (MSRAD) was a closely simulated, end-to-end Mars Sample Return (MSR) mission scenario, with instrumentation, goals, and constraints modeled on the upcoming NASA Mars 2020 rover mission; this paper reports on the post-mission validation of the exercise. The exercise utilized the CSA Mars Exploration Science Rover (MESR) rover, deployed to Utah, USA, at a Mars-analogue field site. The principal features of the field site located near Green River, Utah are Late Jurassic inverted, fluvial paleochannels, analogous to features on Mars in sites being considered for the ESA ExoMars rover mission and present within the chosen landing site for the Mars 2020 rover mission. The in-simulation (“in-sim”) mission operations team worked remotely from The University of Western Ontario, Canada. A suite of MESR-integrated and hand-held spectrometers was selected to mimic those of the Mars 2020 payload, and a Utah-based, on-site team was tasked with field operations to carry out the data collection and sampling as commanded by the in-sim team. As a validation of the in-sim mission science findings, the field team performed an independent geological assessment. This paper documents the field team's on-site geological assessment and subsequent laboratory and analytical results, then offers a comparison of mission (in-sim) and post-mission (laboratory) science results. The laboratory-based findings were largely consistent with the in-sim rover-derived data and geological interpretations, though some notable exceptions highlight the inherent difficulties in remote science. In some cases, available data was insufficient for lithologic identification given the absence of other important contextual information (e.g., textural information). This study suggests that the in-sim instruments were largely adequate for the Science Team to characterize samples; however, rover-based field work is necessarily hampered by mobility and time constraints with an obvious effect on efficiency but also precision, and to some extent, accuracy of the findings. The data show a dearth of preserved total organic carbon (TOC) – used as a proxy for ancient biosignature preservation potential – in the fluvial-lacustrine system of this field site, suggesting serious consideration with respect to the capabilities and opportunities for addressing the Mars exploration goals. We therefore suggest a thorough characterization of terrestrial sites analogous to those of Mars rover landing sites, and in-depth field studies like CanMars as important, pre-mission strategic exercises

Microbial diversity of impact-generated habitats

Impact-generated lithologies have recently been identified as viable and important microbial habitats, especially within cold and arid regions such as the polar deserts on Earth. These unique habitats provide protection from environmental stressors, such as freeze-thaw events, desiccation, and UV radiation, and act to trap aerially deposited detritus within the fissures and pore spaces, providing necessary nutrients for endoliths. This study provides the first culture-independent analysis of the microbial community structure within impact-generated lithologies in a Mars analog environment, involving the analysis of 44,534 16S rRNA sequences from an assemblage of 21 rock samples that comprises three shock metamorphism categories. We find that species diversity increases (H = 2.4-4.6) with exposure to higher shock pressures, which leads to the development of three distinct populations. In each population, Actinobacteria were the most abundant (41%, 65%, and 59%), and the dominant phototrophic taxa came from the Chloroflexi. Calculated porosity (a function of shock metamorphism) for these samples correlates (R2 = 0.62) with inverse Simpson indices, accounting for overlap in populations in the higher shock levels. The results of our study show that microbial diversity is tied to the amount of porosity in the target substrate (as a function of shock metamorphism), resulting in the formation of distinct microbial populations. Key Words: Microbial diversity-Endoliths-Impact melt-rocks-Mars-Astrobiology. Astrobiology 16, 775-786

Toward Prebiotic Chemistry on Titan: Impact Experiments on Organic Haze Particles

Impacts are critical to producing the aqueous environments necessary to stimulate prebiotic chemistry on Titan’s surface. Furthermore, organic hazes resting on the surface are a likely feedstock of biomolecules. In this work, we conduct impact experiments on laboratory-produced organic haze particles and haze/sand mixtures and analyze these samples for life’s building blocks. Samples of unshocked haze and sand particles are also analyzed to determine the change in biomolecule concentrations and distributions from shocking. Across all samples, we detect seven nucleobases, nine proteinogenic amino acids, and five other biomolecules (e.g., urea) using a blank subtraction procedure to eliminate signals due to contamination. We find that shock pressures of 13 GPa variably degrade nucleobases, amino acids, and a few other organics in haze particles and haze/sand mixtures; however, certain individual biomolecules become enriched or are even produced from these events. Xanthine, threonine, and aspartic acid are enriched or produced in impact experiments containing sand, suggesting these minerals may catalyze the production of these biomolecules. On the other hand, thymine and isoleucine/norleucine are enriched or produced in haze samples containing no sand, suggesting catalytic grains are not necessary for all impact shock syntheses. Uracil, glycine, proline, cysteine, and tyrosine are the most unstable to impact-related processing. These experiments suggest that impacts alter biomolecule distributions on Titan’s surface, and that organic hazes co-occurring with fine-grained material on the surface may provide an initial source for further prebiotic chemistry on Titan

CanMars mission Science Team operational results: implications for operations and the sample selection process for Mars Sample Return (MSR)

The CanMars Mars sample return (MSR) analogue mission was conducted as a field and operational test for the Mars 2020 sample cache rover mission and was the most realistic known MSR rover analogue mission to-date. A rover — similar in scale to that of rover planned for NASA's Mars 2020 mission — was deployed to a scientifically relevant Mars-analogue sedimentary field site with remote mission operations conducted at the University of Western Ontario, Canada; the mission aim was to inform on best practices and optimal approaches for sample acquisition modeled on the Mars 2020 rover mission. The daily operational procedures of the CanMars Science Team were modeled on those of current missions (i.e., Mars Science Laboratory tactical operations), serving as a study of known operational workflows and as a testbed for new approaches. This paper reports on the operational results of CanMars with best-practice recommendations. CanMars was designed as a Mars 2020 mock mission and thus carried similar science objectives; these included (1) advancing the understanding of the habitability potential of a subaqueous sedimentary environment through identifying, characterizing, and caching drilled samples containing high organic carbon (as a proxy for preserved ancient biosignatures) and (2) advancing the understanding of the history of water at the site. The in situ science investigations needed to address these science objectives were guided by the Mars Exploration Program Analysis Group goals. Effective and efficient Science Team operational procedures were developed – and many lessons were documented – through daily tactical planning and science investigations employed to meet the sample acquisition goals. In addition to the documentation of the CanMars operational procedures, this paper provides a brief summary of the science results from CanMars with a focus on recommendations for future analogue missions and planetary sample return flight missions, providing specific value to operational procedures for the Mars 2020 rover mission

The CanMars Mars Sample Return analogue mission

The return of samples from known locations on Mars is among the highest priority goals of the international planetary science community. A possible scenario for Mars Sample Return (MSR) is a series of 3 missions: sample cache, fetch, and retrieval. The NASA Mars 2020 mission represents the first cache mission and was the focus of the CanMars analogue mission described in this paper. The major objectives for CanMars included comparing the accuracy of selecting samples remotely using rover data versus a traditional human field party, testing the efficiency of remote science operations with periodic pre-planned strategic observations (Strategic Traverse Days), assessing the utility of realistic autonomous science capabilities to the remote science team, and investigating the factors that affect the quality of sample selection decision-making in light of returned sample analysis. CanMars was conducted over two weeks in November 2015 and continued over three weeks in October and November 2016 at an analogue site near Hanksville, Utah, USA, that was unknown to the Mission Control Team located at the University of Western Ontario (Western) in London, Ontario, Canada. This operations architecture for CanMars was based on the Phoenix and Mars Exploration Rover missions together with previous analogue missions led by Western with the Mission Control Team being divided into Planning and Science sub-teams. In advance of the 2015 operations, the Science Team used satellite data, chosen to mimic datasets available from Mars-orbiting instruments, to produce a predictive geological map for the landing ellipse and a set of hypotheses for the geology and astrobiological potential of the landing site. The site was proposed to consist of a series of weakly cemented multi-coloured sedimentary rocks comprising carbonates, sulfates, and clays, and sinuous ridges with a resistant capping unit, interpreted as inverted paleochannels. Both the 2015 CanMars mission, which achieved 11 sols of operations, and the first part of the 2016 mission (sols 12–21), were conducted with the Mars Exploration Science Rover (MESR) and a series of integrated and hand-held instruments designed to mimic the payload of the Mars 2020 rover. Part 2 of the 2016 campaign (sols 22–39) was implemented without the MESR rover and was conducted exclusively by the field team as a Fast Motion Field Test (FMFT) with hand-carried instruments and with the equivalent of three sols of operations being executed in a single actual day. A total of 8 samples were cached during the 39 sols from which the Science Team prioritized 3 for “return to Earth”. Various science autonomy capabilities, based on flight-proven or near-future techniques intended for actual rover missions, were tested throughout the 2016 CanMars activities, with autonomous geological classification and targeting and autonomous pointing refinement being used extensively during the FMFT. Blind targeting, contingency sequencing, and conditional sequencing were also employed. Validation of the CanMars cache mission was achieved through various methods and approaches. The use of dedicated documentarians in mission control provided a detailed record of how and why decisions were made. Multiple separate field validation exercises employing humans using traditional geological techniques were carried out. All 8 of the selected samples plus a range of samples from the landing site region, collected out-of-simulation, have been analysed using a range of laboratory analytical techniques. A variety of lessons learned for both future analogue missions and planetary exploration missions are provided, including: dynamic collaboration between the science and planning teams as being key for mission success; the more frequent use of spectrometers and micro-imagers having remote capabilities rather than contact instruments; the utility of strategic traverse days to provide additional time for scientific discussion and meaningful interpretation of the data; the benefit of walkabout traverse strategies along with multi-sol plans with complex decisions trees to acquire a large amount of contextual data; and the availability of autonomous geological targeting, which enabled complex multi-sol plans gathering large suites of geological and geochemical survey data. Finally, the CanMars MSR activity demonstrated the utility of analogue missions in providing opportunities to engage and educate children and the public, by providing tangible hands-on linkages between current robotic missions and future human space missions. Public education and outreach was a priority for CanMars and a dedicated lead coordinated a strong presence on social media (primarily Twitter and Facebook), articles in local, regional, and national news networks, and interaction with the local community in London, Ontario. A further core objective of CanMars was to provide valuable learning opportunities to students and post-doctoral fellows in preparation for future planetary exploration missions. A learning goals survey conducted at the end of the 2016 activities had 90% of participants “somewhat agreeing” or “strongly agreeing” that participation in the mission has helped them to increase their understanding of the four learning outcomes

Impact-generated hydrothermal systems on Earth and Mars

It has long been suggested that hydrothermal systems might have provided habitats for the origin and evolution of early life on Earth, and possibly other planets such as Mars. In this contribution we show that most impact events that result in the formation of complex impact craters (i.e., >2-4 and >5-10. km diameter on Earth and Mars, respectively) are potentially capable of generating a hydrothermal system. Consideration of the impact cratering record on Earth suggests that the presence of an impact crater lake is critical for determining the longevity and size of the hydrothermal system. We show that there are six main locations within and around impact craters on Earth where impact-generated hydrothermal deposits can form: (1) crater-fill impact melt rocks and melt-bearing breccias; (2) interior of central uplifts; (3) outer margin of central uplifts; (4) impact ejecta deposits; (5) crater rim region; and (6) post-impact crater lake sediments. We suggest that these six locations are applicable to Mars as well. Evidence for impact-generated hydrothermal alteration ranges from discrete vugs and veins to pervasive alteration depending on the setting and nature of the system. A variety of hydrothermal minerals have been documented in terrestrial impact structures and these can be grouped into three broad categories: (1) hydrothermally-altered target-rock assemblages; (2) primary hydrothermal minerals precipitated from solutions; and (3) secondary assemblages formed by the alteration of primary hydrothermal minerals. Target lithology and the origin of the hydrothermal fluids strongly influences the hydrothermal mineral assemblages formed in these post-impact hydrothermal systems. There is a growing body of evidence for impact-generated hydrothermal activity on Mars; although further detailed studies using high-resolution imagery and multispectral information are required. Such studies have only been done in detail for a handful of martian craters. The best example so far is from Toro Crater (Marzo, G.A., Davila, A.F., Tornabene, L.L., Dohm, J.M., Fairèn, A.G., Gross, C., Kneissl, T., Bishop, J.L., Roush, T.L., Mckay, C.P. [2010]. Icarus 208, 667-683). We also present new evidence for impact-generated hydrothermal deposits within an unnamed ∼32-km diameter crater ∼350. km away from Toro and within the larger Holden Crater. Synthesizing observations of impact craters on Earth and Mars, we suggest that if there was life on Mars early in its history, then hydrothermal deposits associated with impact craters may provide the best, and most numerous, opportunities for finding preserved evidence for life on Mars. Moreover, hydrothermally altered and precipitated rocks can provide nutrients and habitats for life long after hydrothermal activity has ceased