Quantitative 3D analysis and validation of terrestrial analogues for ancient martian habitable environments in preparation for the 2018 ExoMars Rover

PanCam will provide imagery of Mars’ surface that will allow reconstruction by 3-D digital terrain mapping. It will also provide context for drill sampling and rover instrumentation. The wide-angle cameras will provide stereo information while the high-resolution camera will enable close-up images of martian structures and features.

The question as to whether life arose elsewhere in the Universe is arguably one of the most significant science questions to challenge humankind. Mars being the most Earth-like of planets has been the focus of significant science investigation. The exploration and search for life on Mars is a one of the primary goals of International Solar System exploration. The ExoMars 2018 Rover mission is planned to land on Mars in 2019, to; 1) search for signs of past and present life, and; 2) investigate the water/geochemical environment as a function of depth in the shallow subsurface. The search for evidence of life is an exceptionally difficult problem. On Earth, sediments and sedimentary rocks, in particular those formed by or in water, are where we find fossil life and other biosignatures best preserved, and such sediments are ideal targets for the ExoMars rover mission. The main goal of ExoMars is to drill into subsurface rocks to search for evidence of ancient microbial life. The final four candidate landing sites for the mission all contain extensive sedimentary rock outcrops considered to provide physical or chemical evidence for ancient habitable environments. Once the rover lands, one of its prime goals will be to analyse outcrops of sedimentary rocks and assess their potential for habitability and potential to contain ancient microbial life. Initial outcrops encountered will provide clues for how the rover should plan its search strategy. Thus techniques and tools for analysing sedimentary rock outcrops are crucial to developing efficient exploration strategies. One of the primary instruments being sent with the ExoMars Rover, as part of the PASTEUR payload, is the UK-led Panoramic Camera (PanCam) instrument. The PanCam serves as the 'eyes' of the rover. Scientists on the ExoMars team will use the PanCam to view the Martian landscape and search for rock outcrops to conduct detailed investigations upon. Once suitable and interesting rock outcrops have been identified and the rover has approached for closer views, the PanCam instrument will be used to characterise features of the rock outcrop that provide clues as to how the rocks were originally deposited as sediments. These clues are preserved in the geometry of layers that make up rock outcrops, internal features within layers and the size and texture of grains that form the sediment. On Earth to do this accurately we make measurements in 3 dimensions of geological features in rock outcrops. The PanCam instrument can take stereo images which can be used to construct 3-D topographic data for rock outcrops. Analysis of these 3-D models of rock outcrops enables us to analyse rock outcrops much like geologists might do on Earth. This proposal addresses an outstanding question as to how accurate our quantitative measurements of features in rock outcrops are? How robust are the data we use to make important interpretations of the ancient geological environment on Mars? We propose to use the Aberystwyth University PanCam Emulator (AUPE-2) - a PanCam field instrument for use on Earth - to collect new 3-D data of outcrops of sedimentary rocks in the UK which show evidence of palaeoenvironments comparable to those seen on Mars. The goal is to take field measurements of carefully selected outcrops, then image them with the AUPE-2 stereo equipment. Quantitative analysis of the PanCam data will be compared with measurements manually taken in the field at the same points on the outcrops. This will enable us to assess the accuracy of 3-D data taken with the PanCam instrument on Mars. Our project will ensure that accurate 3-D data, and the means to view and analyse it, is accessible in real-time for ExoMars mission planners, and that the 3-D data can be fully exploited by scientists during and after the mission. The dataset collected by us will also provide training datasets for scientists to become familiar with quantitative analysis of rock outcrops prior to mission commencement.