Remote detection of past habitability at Mars-analogue hydrothermal alteration terrains using an ExoMars Panoramic Camera emulator

Abstract

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

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

“…PanCam comprises three cameras mounted The PanCam flight instrument is still under development and so an emulator camera system has been constructed to provide representative data during field testing. Specification differences between the AUPE-2 system and ExoMars PanCam can be found in Harris et al (2015). The Aberystwyth University PanCam Emulator MK2 (AUPE-2) used for MINAR is constructed from a combination of commercial off-the-shelf cameras and lenses, and bespoke filter wheels (Cousins et al 2012) and control software.…”

Multiscale and Multispectral Characterization of Mineralogy with the ExoMars 2022 Rover Remote Sensing Payload

“…The second outcrop (“Pillow_Alt”) is also weathered and has additionally undergone extensive secondary alteration and displays crosscutting gypsum veins. These outcrops were previously imaged with an earlier iteration of AUPE3 in Harris et al () as A07_Pillow and A08_Veins, respectively. These deposits in combination with their alteration phases provide an example of low‐temperature (<150 ° C) neutral‐acidic alteration of basaltic material.…”

“…As prolonged, aqueous Martian environments may have been habitable to microorganisms (Vago et al, ), we deployed instrument emulators in areas hosting minerals which had formed in a range of aqueous environments to assess potential science targets. These areas included large‐scale sedimentary depositional systems (Torrey, Utah, USA; Tjörnes, Iceland) and systems displaying authigenic low‐temperature alteration of basalt (Námafjall, Iceland) that host deposits of phyllosilicates, sulfates, zeolites, and iron oxides (Harris et al, ; Michalski et al, ; Murchie et al, ).…”

“…PanCam RGB imaging differs from that of Mastcam (Malin et al, ) (onboard NASAs Mars Science Laboratory (MSL) rover Curiosity ) and Mastcam‐Z (Bell et al, ) (onboard NASAs upcoming Mars2020 rover mission) in that PanCam uses these broadband color filters instead of RGB Bayer filters (Bell et al, ; Wellington et al, ). PanCam emulator data are provided by the Aberystwyth University PanCam Emulator 3 (AUPE3), which has been built with off‐the‐shelf components to replicate ExoMars PanCam specifications as closely as possible and is designed for use in Mars analog terrains (Harris et al, ). When deployed, AUPE3 is mounted on an optical bench (alongside ISEM‐E and HRC‐E) 2 m above the ground to replicate its position on the ExoMars mast.…”

“…When deployed, AUPE3 is mounted on an optical bench (alongside ISEM‐E and HRC‐E) 2 m above the ground to replicate its position on the ExoMars mast. The FOV of AUPE3 is 34° , slightly smaller than that of PanCam, and in place of the PanCam solar filters in positions 10 and 11, there is a luminance filter covering the visible portion of the spectrum and an empty filter slot for panchromatic imaging (Harris et al, ). Details of the filter wheels in Left WAC (LWAC) and Right WAC (RWAC) cameras for AUPE3 versus the ExoMars PanCam are provided in Table .…”