Characterization and first results of the planetary borehole-wall imager — methods to develop for in-situ exploration

Ákos Kereszturi,Gyula Maros,Ludovic Duvet,Ákos Gyenis,Bálint Kovács,Zsuzsanna Kapui,Tamás Gyenis,Gyula Gróf

doi:10.1515/astro-2019-0001

Abstract

Abstract Prototypes of borehole-wall imager instruments were developed and tested at a desert riverbed in Morocco and at a lake’s salty flat in the Atacama desert, to support the drilling activity of ExoMars rover. The onsite recorded borehole images contain information on the context that are lost during the sample acquisition. Benefits of the borehole-wall imaging is the easier maximal energy estimation of a fluvial flow, the detailed information on sedimentation and layering, especially the former existence of liquid water and its temporal changes, including paleo-flow direction estimation from grain imbrication direction. Benefits of laboratory analysis of the acquired samples are the better identification of mineral types, determination of the level of maturity of granular sediment, and identification of the smallest, wet weathered grains. Based on the lessons learned during the comparison of field and laboratory results, we demonstrate that recording the borehole-wall with optical instrument during/after drilling on Mars supports the paleo-environment reconstruction with such data that would otherwise be lost during the sample acquisition. Because of the lack of plate tectonism and the low geothermal gradient on Mars, even Ga old sediments provide observable features that are especially important for targeting Mars sample return and later crewed Mars missions.

Highlights

The aim of this work is to compare the potential results of two different in-situ sample analysing methods for planetary bodies: the poorly tested optical scanning of boreholewall and the more widely used optical analysis under laboratory conditions of the acquired sample
Based on the lessons learned during the comparison of field and laboratory results, we demonstrate that recording the borehole-wall with optical instrument during/after drilling on Mars supports the paleo-environment reconstruction with such data that would otherwise be lost during the sample acquisition
While in the first case the samples are surveyed as they are embedded in their original environment, in the second case the collected samples are analysed without their original context. (For more detailed background information on these methods please see the subchapter.) Future Mars missions

Summary

Introduction

The aim of this work is to compare the potential results of two different in-situ sample analysing methods for planetary bodies: the poorly tested optical scanning of boreholewall and the more widely used optical analysis under laboratory conditions of the acquired sample. (For more detailed background information on these methods please see the subchapter.) Future Mars missions. During the Mars sample return and especially planned future crewed mission, the sample selection on Mars requires careful work, and the efficiency of sample targeting and selection should be supported by such local analysis that provides information on the depositional conditions and local context too. As old sedimentary strata might hold information on habitable conditions, on-site analysis of the borehole-wall during the drill is helpful. The related technology and the first results for such analysis is presented

Objectives

Methods

Results

Discussion

Conclusion