Rosalba Bonaccorsi

Astrobiology through the Ages of Mars: The Study of Terrestrial Analogues to Understand the Habitability of Mars

Mars has undergone three main climatic stages throughout its geological history, beginning with a water-rich epoch, followed by a cold and semi-arid era, and transitioning into present-day arid and very cold desert conditions. These global climatic eras also represent three different stages of planetary habitability: an early, potentially habitable stage when the basic requisites for life as we know it were present (liquid water and energy); an intermediate extreme stage, when liquid solutions became scarce or very challenging for life; and the most recent stage during which conditions on the surface have been largely uninhabitable, except perhaps in some isolated niches. Our understanding of the evolution of Mars is now sufficient to assign specific terrestrial environments to each of these periods. Through the study of Mars terrestrial analogues, we have assessed and constrained the habitability conditions for each of these stages, the geochemistry of the surface, and the likelihood for the preservation of organic and inorganic biosignatures. The study of these analog environments provides important information to better understand past and current mission results as well as to support the design and selection of instruments and the planning for future exploratory missions to Mars.

The 2005 MARTE Robotic Drilling Experiment in Río Tinto, Spain: Objectives, Approach, and Results of a Simulated Mission to Search for Life in the Martian Subsurface

The Mars Astrobiology Research and Technology Experiment (MARTE) simulated a robotic drilling mission to search for subsurface life on Mars. The drill site was on Peña de Hierro near the headwaters of the Río Tinto river (southwest Spain), on a deposit that includes massive sulfides and their gossanized remains that resemble some iron and sulfur minerals found on Mars. The mission used a fluidless, 10-axis, autonomous coring drill mounted on a simulated lander. Cores were faced; then instruments collected color wide-angle context images, color microscopic images, visible-near infrared point spectra, and (lower resolution) visible-near infrared hyperspectral images. Cores were then stored for further processing or ejected. A borehole inspection system collected panoramic imaging and Raman spectra of borehole walls. Life detection was performed on full cores with an adenosine triphosphate luciferin-luciferase bioluminescence assay and on crushed core sections with SOLID2, an antibody array-based instrument. Two remotely located science teams analyzed the remote sensing data and chose subsample locations. In 30 days of operation, the drill penetrated to 6 m and collected 21 cores. Biosignatures were detected in 12 of 15 samples analyzed by SOLID2. Science teams correctly interpreted the nature of the deposits drilled as compared to the ground truth. This experiment shows that drilling to search for subsurface life on Mars is technically feasible and scientifically rewarding.

SOLID2: an antibody array-based life-detector instrument in a Mars Drilling Simulation Experiment (MARTE).

A field prototype of an antibody array-based life-detector instrument, Signs Of LIfe Detector (SOLID2), has been tested in a Mars drilling mission simulation called MARTE (Mars Astrobiology Research and Technology Experiment). As one of the analytical instruments on the MARTE robotic drilling rig, SOLID2 performed automatic sample processing and analysis of ground core samples (0.5 g) with protein microarrays that contained 157 different antibodies. Core samples from different depths (down to 5.5 m) were analyzed, and positive reactions were obtained in antibodies raised against the Gram-negative bacterium Leptospirillum ferrooxidans, a species of the genus Acidithiobacillus (both common microorganisms in the Río Tinto area), and extracts from biofilms and other natural samples from the Río Tinto area. These positive reactions were absent when the samples were previously subjected to a high-temperature treatment, which indicates the biological origin and structural dependency of the antibody-antigen reactions. We conclude that an antibody array-based life-detector instrument like SOLID2 can detect complex biological material, and it should be considered as a potential analytical instrument for future planetary missions that search for life.

MARTE: Technology development and lessons learned from a Mars drilling mission simulation

29 pages, 21 figures, 2 tables.-- ISI Article Identifier: 000250768000006.-- Special issue: Mining Robotics.

Design and practices for use of automated drilling and sample handling in MARTE while minimizing terrestrial and cross contamination.

Mars Astrobiology Research and Technology Experiment (MARTE) investigators used an automated drill and sample processing hardware to detect and categorize life-forms found in subsurface rock at Río Tinto, Spain. For the science to be successful, it was necessary for the biomass from other sources--whether from previously processed samples (cross contamination) or the terrestrial environment (forward contamination)-to be insignificant. The hardware and practices used in MARTE were designed around this problem. Here, we describe some of the design issues that were faced and classify them into problems that are unique to terrestrial tests versus problems that would also exist for a system that was flown to Mars. Assessment of the biomass at various stages in the sample handling process revealed mixed results; the instrument design seemed to minimize cross contamination, but contamination from the surrounding environment sometimes made its way onto the surface of samples. Techniques used during the MARTE Río Tinto project, such as facing the sample, appear to remove this environmental contamination without introducing significant cross contamination from previous samples.

Biomass and habitability potential of clay minerals- and iron-rich environments: Testing novel analogs for Mars Science Laboratory landing sites candidates

The landing site of the next mission to Mars (the US 2011 Mars Science Laboratory) will include phyllosilicate outcrops as targets for investigating the geological and biological history of the planet. In this context, we present a preliminary study assessing the living biomass and habitability potential in mineralogical Mars analogs by means of multi-component investigations (X-ray diffraction, microRaman spectroscopy and SEM\EDX). Phyllosilicate and hematite-rich deposits from the Atacama Desert (Chile), Death Valley (CA), and the California Coast, encompassing a broad arid to hyper-arid climate range (annual rainfall <0.2 to ∼700 mm/year), were analyzed for total and viable Gram-negative biomass, i.e. adenosine 5′-triphosphate (ATP) and Limulus amebocyte lysate (LAL) assays. Basic observations were: (1) there is no systematic pattern in biomass content of clay-rich versus non-clay (oxidized) materials; (2) Atacama desiccation polygons (6.0 × 104 cells/g) and contiguous hematite-rich deposits contain the lowest biomass (1.2 × 105 cells/g), which is even lower than that of coarse-grained soil nearby (3.3–5.0 × 105 cells/g); (3) the Atacama clay-rich samples (illite–muscovite and kaolinite) are three orders of magnitude lower than surface clay (montmorillonite, illite, and chlorite) from Death Valley; and (4) finally, and unexpectedly, the Gram-negative content (∼6.4 × 107 cells/g) of clay mineral-rich materials from the arid Death Valley region is up to six times higher than that (∼1.5 to ∼3.0 × 107 cells/g) of water-saturated massive clays (kaolinite, illite and montmorillonite) from the California Coast (wetter end-member). MicroRaman spectroscopy investigation on a Death Valley sample indicates that gypsum (1008, 618, and 414 cm–1 Raman shift), and inferred associated organic (scytonemin) biosignatures (1281 cm–1) for the measured Gram-negatives (cyanobacteria) were successfully captured.

Subsurface scientific exploration of extraterrestrial environments (MINAR 5): analogue science, technology and education in the Boulby Mine, UK

The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.

Raman imaging for high throughput biomarker field detections

We explore the feasibility of using Raman imaging as a technique for identifying areas of high astrobiological interest on Mars-like surfaces. This paper will discuss the technique, analysis, and possible deployment of rover mounted instrumentation for identifying biogenic samples from Mars analog environments, such as the Mojave Desert and Lassen Volcanic National Park. We also discuss using this technique for the non-destructive, in situ identification snow algae found in harsh environments.