The scientific objectives of the ExoMars rover are designed to answer several key questions in the search for life on Mars. In particular, the unique subsurface drill will address some of these, such as the possible existence and stability of subsurface organics. PanCam will establish the surface geological and morphological context for the mission, working in collaboration with other context instruments. Here, we describe the PanCam scientific objectives in geology, atmospheric science, and 3-D vision. We discuss the design of PanCam, which includes a stereo pair of Wide Angle Cameras (WACs), each of which has an 11-position filter wheel and a High Resolution Camera (HRC) for high-resolution investigations of rock texture at a distance. The cameras and electronics are housed in an optical bench that provides the mechanical interface to the rover mast and a planetary protection barrier. The electronic interface is via the PanCam Interface Unit (PIU), and power conditioning is via a DC-DC converter. PanCam also includes a calibration target mounted on the rover deck for radiometric calibration, fiducial markers for geometric calibration, and a rover inspection mirror. Key Words: Mars—ExoMars—Instrumentation—Geology—Atmosphere—Exobiology—Context. Astrobiology 17, 511–541.
This paper is dedicated to the late Prof. Dave Barnes who sadly passed away before the publication of this work, to which he had significantly contributed over the years through his work on the ExoMars PanCamA major scientific goal of the European Space Agency?s ExoMars 2018 rover is to identify evidence of life within the martian rock record. Key to this objective is the remote detection of geological substrates that are indicative of past habitable environments, which will rely on visual (stereo wide-angle, and high resolution images) and multispectral (440?1000 nm) data produced by the Panoramic Camera (PanCam) instrument. We deployed a PanCam emulator at four hydrothermal sites in the N?mafjall volcanic region of Iceland, a Mars-analogue hydrothermal alteration terrain. At these sites, sustained acidic?neutral aqueous interaction with basaltic substrates (crystalline and sedimentary) has produced phyllosilicate, ferric oxide, and sulfate-rich alteration soils, and secondary mineral deposits including gypsum veins and zeolite amygdales. PanCam emulator datasets from these sites were complemented with (i) NERC Airborne Research and Survey Facility aerial hyperspectral images of the study area; (ii) in situ reflectance spectroscopy (400?1000 nm) of PanCam spectral targets; (iii) laboratory X-ray Diffraction, and (iv) laboratory VNIR (350?2500 nm) spectroscopy of target samples to identify their bulk mineralogy and spectral properties. The mineral assemblages and palaeoenvironments characterised here are analogous to neutral?acidic alteration terrains on Mars, such as at Mawrth Vallis and Gusev Crater. Combined multispectral and High Resolution Camera datasets were found to be effective at capturing features of astrobiological importance, such as secondary gypsum and zeolite mineral veins, and phyllosilicate-rich substrates. Our field observations with the PanCam emulator also uncovered stray light problems which are most significant in the NIR wavelengths and investigations are being undertaken to ensure that the flight model PanCam cameras are not similarly affectedpublishersversionPeer reviewe
Abstract. The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research -MINAR (MINe Analog Research). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator (AUPE-2), Close-Up Imager (CLUPI), Raman Spectrometer, SPLIT (Small Planetary Linear Impulse Tool), Ultrasonic Drill and handheld XRD. We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimeter to meter scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining. IntroductionPlanetary analog research involves the investigation of terrestrial environments that are comparable to extraterrestrial environments. These analogs tend to be focused, at a high level, on science, science operations, or technology research and testing, or a combination of these topics (e.g. Dickinson and Rosen 2003;Sarrazin et al. 2005; Cabrol et al. 2007;Pollard et al. 2009; Lim et al. 2011;Abercromby et al. 2013). Analog field settings are used to evaluate scientific instruments of particular relevance to future flight missions in a rugged field setting. These field tests have, for example, ranged from deserts to underwater settings (e.g. Cabrol et al. 2007;Jasiobedzki et al. 2012;Abercromby et al. 2013), and have taken a variety of forms, from testing a single technology to examine its performance in a particular environment (e.g. Skelley et al. 2007), to fully integrated rover tests utilizing a variety of different instruments (e.g. Schenker et al. 2001).One environment that has received less attention for analog research, but which holds a great deal o...
Noebels, M., Cross, R. E., Evans, D. A., & Finlayson, C. E. (2014). Characterization of spray-coating methods for conjugated polymer blend thin films. Journal of Materials Science, 49(12), 4279-4287We examine the characteristics and functionality of conjugated polymer thin films, based on blends of poly(9,9-dioctylfluorene-2,7-diyl-co-bis-N,NN'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT), using a spray-coating deposition technique suitable for large areas. The morphological properties of these blend films are studied in detail by atomic force microscopy (AFM) methods, showing that favourable results, in terms of layer deposition rate and uniformity, can be achieved using a 5:1 blend of o-dichlorobenzene and chlorobenzene as the solvent medium. A photoluminescence quenching efficiency of above 80 % is also observed in such blend films. As a feasibility study, prototypical photovoltaic devices exhibit open circuit voltages of up to 1.0 V under testing, and solar power conversion efficiencies in the 0.1-1 % order of magnitude; metrics which are comparable with those reported for spin-coated cells of the same active blend and device architecture.authorsversionPeer reviewe
In recent years a number of portable instruments have been built for measuring the optically stimulated luminescence (OSL) signal from naturally occurring minerals. Some of these instruments have incorporated ionising radiation sources, giving the possibility of determining an equivalent dose (D e), but little use has been made of these. One challenge has been that heating samples in this type of equipment is a major engineering challenge, yet methods for D e determination use thermal pretreatments to remove charge from unstable traps, making signals arising from irradiation in nature and the laboratory comparable. This paper explores three strategies for obtaining accurate estimates of the D e of samples in situations where thermal treatments are not possible: (1) deriving a correction factor based on comparing D e values obtained using protocols with and without heating; (2) removing the contribution from the 110°C TL peak and other unstable defects by component fitting the unheated OSL signal; and (3) adding a small beta dose to the sample prior to measurement of the natural luminescence signal so that the 110°C TL peak is filled, making this measurement comparable with regeneration measurements where this peak is also populated. All three methods are promising when applied to quartz that has been physically separated from samples using standard laboratory procedures. The next step in
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