Rock Abrasion Tool: Mars Exploration Rover mission

Gorevan, S.; Myrick, T.; Davis, K.; Chau, J.J.; Bartlett, Paul; Mukherjee, Shatavisa; Anderson, Robert C.; Squyres, S. W.; Arvidson, R. E.; Madsen, M. B.; Bertelsen, Preben; Goetz, W.; Binau, C. S.; Richter, Lutz

doi:10.1029/2003je002061

Cited by 139 publications

(97 citation statements)

References 16 publications

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“…When the MAHLI investigation was proposed in 2004, one of its objectives centered on examination of rock surfaces exposed by a grinding tool similar to the Rock Abrasion Tool (RAT) aboard the Spirit and Opportunity rovers (Gorevan et al 2003). The RAT helped reveal rock coatings and rinds, the presence and crystal shape of phenocrysts in basalt, and the relationship between concretions and matrix in sandstone (e.g., Herkenhoff et al 2004b).…”

Section: Impact Of De-scope Of the Msl Surface Removal Toolmentioning

confidence: 99%

Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation

et al. 2012

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The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ∼5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ∼2.1 cm to infinity. At the minimum working distance, image pixel scale is ∼14 µm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI's resolution is comparable at ∼30 µm per pixel. Onboard capabilities include autofocus, autoexposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

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Section: Impact Of De-scope Of the Msl Surface Removal Toolmentioning

confidence: 99%

Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation

et al. 2012

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“…The Mössbauer Spectrometer measures the resonant absorption of gamma rays produced by a ^^Co source to determine splitting of nuclear energy levels in ^^Fe atoms, revealing the mineralogy and oxidation state of Fe-bearing phases. The instrument arm also carries a Microscopic Imager [MI (P)] that has been used to obtain highresolution (30 jjim/pixel) images of rock and soil surfaces and a Rock Abrasion Tool [RAT (10)] that can remove up to ~5 mm of material over a circular area 45 mm in diameter. Finally, the payload includes the Magnetic Properties Experiment consisting of seven magnets that have attracted fine-grained magnetic materials for viewing by payload instruments (11).…”

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confidence: 99%

The Spirit Rover's Athena Science Investigation at Gusev Crater, Mars

Squyres¹

2004

Science

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117

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The Mars Exploration Rover Spirit and its Atliena science payload liave been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former lake, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. I^jany rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.Spirit landed in Gusev crater on 4 January 2004 UTC. It was followed 21 days later by Opportunity, which landed on Meridiani Planurn. Both vehicles landed using a variant of the airbag landing system that was developed for the Mars Pathfinder mission, deploying the rovers after the landers had come to rest on the surface (1). The primary scientific objective of their mission is to explore two sites on the martian surface where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. Here we provide an overview of the results from the 90-sol (2) nominal mission of Spirit.Like Opportunity, Spirit carries a copy of the Athena science payload (3) (Fig. 1). The topography, morphology, and mineralogy of the scene around the rover have been revealed by two remote sensing instruments: a panoramic camera (Pancam) and a miniature thermal emission spectrometer (Mini-TES). Pancam (4) is a stereo camera whose filters provide 11 unique color spectral bandpasses over the spectral region from 0.4 to 1.1 mm, as well as two other filters for direct imaging of the Sun. Mini-TES (5) produces high spectral resolution (10 cm^') infrared image cubes with a wavelength range of 5 to 29 jjim. The Pancam cameras and the Mini-TES scanning mirrors are mounted atop a mast (3) at a height of ~ 1.5 m above the ground.Once potential science targets have been identified using Pancam and Mini-TES, they have been studied in more detail with the use of two in situ compositional sensors mounted on a 5-degree-of-freedom robotic arm (3). These are an Alpha Particle-X-Ray Spectrometer [APXS (6)] and a Mössbauer Spectrometer (7). Radioactive ^^^Cm alpha sources and two detection modes (alpha and x-ray) in the APXS reveal elemental abundances of rocks and soils (8). The Mössbauer Spectrometer measures the resonant absorption of gamma rays produced by a ^^Co source to determine splitting of nuclear energy levels in ^^Fe atoms, revealing the mineralogy and oxidation state of Fe-bearing phases. The instrument arm also carries a Microscopic Imager [MI (P)] that has been used to obtain highresolution (30 jjim/pixel) images of rock and soil surfaces and a Rock Abrasion Tool [ RAT (10)] that can remove up to ~5 mm of material over a circular area 45 mm in diameter. Finally, the payload includes the Magnetic Properties Experiment consisting of seven magnets that hav...

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“…A rock abrasion tool (RAT) such as carried by the Mars Exploration Rovers Spirit and Opportunity (Gorevan et al 2003), the rock coring drill on Mars Science Laboratory (Okon 2010) and the 2 m subsurface drill proposed for ExoMars (Vago et al 2006) are all appropriate devices for this. Once exposed to the unfiltered solar UV spectrum on the Martian surface, however, any potential fluorophores will be readily photodegraded and their fluorescence signal lost.…”

Section: Rationalementioning

confidence: 99%

Degradation of microbial fluorescence biosignatures by solar ultraviolet radiation on Mars

Dartnell

Patel

2013

International Journal of Astrobiology

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Recent and proposed robotic missions to Mars are equipped with implements to expose or excavate fresh material from beneath the immediate surface. Once brought into the open, any organic molecules or potential biosignatures of present or past life will be exposed to the unfiltered solar ultraviolet (UV) radiation and face photolytic degradation over short time courses. The key question, then, is what is the window of opportunity for detection of recently exposed samples during robotic operations? Detection of autofluorescence has been proposed as a simple method for surveying or triaging samples for organic molecules. Using a Mars simulation chamber we conduct UV exposures on thin frozen layers of two model microorganisms, the radiation-resistant polyextremophile Deinococcus radiodurans and the cyanobacterium Synechocystis sp. PCC 6803. Excitation-emission matrices (EEMs) are generated of the full fluorescence response to quantify the change in signal of different cellular fluorophores over Martian equivalent time. Fluorescence of Deinococcus cells, protected by a high concentration of carotenoid pigments, was found to be relatively stable over 32 h of Martian UV irradiation, with around 90% of the initial signal remaining. By comparison, fluorescence from protein-bound tryptophan in Synechocystis is much more sensitive to UV photodegradation, declining to 50% after 64 h exposure. The signal most readily degraded by UV irradiation is fluorescence of the photosynthetic pigments -diminished to only 35% after 64 h. This sensitivity may be expected as the biological function of chlorophyll and phycocyanin is to optimize the harvesting of light energy and so they are readily photobleached. A significant increase in a *450 nm emission feature is interpreted as accumulation of fluorescent cellular degradation products from photolysis. Accounting for diurnal variation in Martian sunlight, this study calculates that frozen cellular biosignatures would remain detectable by fluorescence for at least several sols; offering a sufficient window for robotic exploration operations.

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Rock Abrasion Tool: Mars Exploration Rover mission

Cited by 139 publications

References 16 publications

Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation

Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation

The Spirit Rover's Athena Science Investigation at Gusev Crater, Mars

Degradation of microbial fluorescence biosignatures by solar ultraviolet radiation on Mars

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