A Flying Rover for Multi-environment,
Field Science-Based Biosignature Detection
Mother Goose is a combination flyer/rover transformer with a deployable micro-robotic minifleet and rover-mounted high resolution microanalysis mission that searches for biosignatures of past life and biomarkers of possible current life in a variety of potential site types. Its guiding strategy, imaging, and experiments at a series of different spatial scales, robotically reproduce the actual successful behaviors of human field scientists . Three primary scales of investigation are included: bird’s eye view on the flyer for regional scale reconnaissance (10’s to 100’s km), eyeball to hand-lens scale view on the rover and micro-robots (km to mm) and microscopic view via high-resolution microscopy and microspectroscopy (100mm - sub-mm). Several different intercomparable data types (imaging and spectroscopy) provide a high degree of interpretability of results.
This mission concept is an outgrowth of ideas generated under the on-going NIAC (NASA Institute for Advanced Concepts) Phase I grant to PI, P. J. Boston titled "Extraterrestrial Caves as Scientific Target and Human Exploration Resource" (http://www.niac.usra.edu/) for the use of microrobotic devices to explore extraterrestrial caves as science targets and future resources for human exploration.
Science Goals and Objectives
The search for biosignatures of past life and indicators of potential present life on Mars depends upon recognition of structures, textures, and data sets at widely varying spatial scales . In this sense, the search for life and its traces on Mars is a classical field science investigation. The cascading continuum of finer scales at which scientists operate requires an instrument set and adequate mobility to address specific points along this continuum at sequentially finer resolutions. In addition, at least several different data types are essential to interpret nonambiguously the results (for example, images, mineral composition, and isotopic fractionation). Thus, we can construct a logic matrix composed of the intersection of data modalities and scales to provide a highly systematic and predictable sequence of mission science events and tasks while simultaneously allowing for the natural intellectual and opportunity-driven flexibility that is inherent to all of human science. This approach mimics the natural and highly successful behaviors of a human field scientist in action.
The single most daunting challenge facing the search for biosignatures and protected microniches that may harbor extant life or recent remains is narrowing down the search field from the planetary and large regional scale to the level at which microscopy and ultra-analytical techniques can be useful. We address this critical requirement by combining imaging capabilities at bird’s-eye, human’s eye, and microbe’s eye scales using visible and autofluorescent wavelengths in various imaging devices coupled with the powerful techniques of Raman spectroscopy, FTIR, x-ray diffraction, and potentially others (EELS, SIMS, Ion microprobe) to yield a matrix of results.
Human-mimetic search strategies involve discrimination of interesting textural, color, and other features against a more uniform background. Pattern recognition software coupled with real-time human decision-making during critical mission events and flexible mid-course correction opportunities can provide an effective cyber-human hybrid guidance and selection capability.
The first level of selection of study site involves image-based and Thermal Emission Spectrometry (TES) aerial reconnaissance to look for likely primary investigation sites. For example, a good field paleontologist can spot a chunk of possible dinosaur bone or petrified log eroding out of an outcrop from a low-flying airplane. We propose a flyer based reconnaissance phase flying at the 700-1500 m altitude over candidate sites selected from the results of prior missions and orbital imaging, mapping, and analysis. These sites include sedimentary basins, volcanic fields, polar margins, canyon bottoms, fluvial and volatile-sapping or collapse features, lava tube caves, and other potential cavities with surface or near-surface openings.
When a human investigator spots a likely site, the eyeball and hand lens come into play, possibly accompanied by simple non-imaging chemical techniques (e.g. the pH meter, dropper bottle of weak HCl to identify carbonates, etc.) We provide this level of analysis with cameras, a dissecting microscope level of resolution and limited simple non-imaging analysis at this intermediate scale level. A rover platform provides human walking-scale mobility coupled with miniature robotic arms fitted with various end-effectors to provide sample acquisition and manipulation capabilities. A flexible, optical fiber fitted probe "finger" on one of the robotic arms allows penetration into otherwise unreachable crevices, cracks, under rock surfaces, overhangs and the like. A small flock of micro-robots, fitted with simple sensors of various types (e.g. chemical sensors for reduced gases, simple microcams, etc.) are deployed from the Mother Goose rover. These provide a wider sampling capability from the immediate environment and refine understanding of the most promising sites for the intensive phase of the investigation to follow. Additionally, such expendable simple robotic units using autonomous distributed-intelligence control can find their ways into otherwise inaccessible sites like lava tubes, sinkhole depressions, small caves and cavities in sedimentary materials, crevices in canyon walls, cryoconite-like holes and non-thermal ice springs in polar terrains. They can perform both in situ sensing and microsample retrieval for later analysis by Mother Goose’s primary instrumentation.
When a promising site does, indeed, prove fruitful at the intermediate scale, intensive ultrahigh resolution, and Mother Goose’s most powerful analytical capabilities come into play. We use a combination of 3D confocal microscopy at visible and fluorescent wavelengths coupled with Raman spectroscopy, SEM and low voltage ESEM, and X-ray diffraction/fluorescence to provide the laboratory level of analysis necessary to interpret complex potential biosignatures.
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