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Date Permissions Signed

3-5-2021

Date of Award

Winter 2021

Document Type

Masters Thesis

Department or Program Affiliation

Geology

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Rice, Melissa S.

Second Advisor

Kraft, Michael

Third Advisor

Mulcahy, Sean

Abstract

The Mars 2020 rover Perseverance will search for signs of past habitability and biosignatures after landing in Jezero Crater in February 2021. Spectroscopy is a vital tool for planetary remote sensing and Perseverance is equipped with Mastcam-Z, a stereoscopic, zoom-enabled, multispectral imager that can acquire true color images with red, green, and blue (RGB) color filters, and visible- to near-infrared images with 12 narrowband science filters between 400 and 1100 nm. Mastcam-Z will provide operational support for the rover as well as directly contribute to Perseverance’s geologic investigations. Given the integral role of Mastcam-Z in the Mars 2020 mission, calibration and validation of Mastcam-Z is crucial. In this study, spectra of a collection of terrestrial rock samples, lab-manufactured color targets, and other image assessment targets, collectively known as the Geoboard, collected by Mastcam-Z during calibration are compared to hyperspectral laboratory data of the same targets collected at Western Washington University (WWU). Comparison of lab and calibration data largely validates the radiometric calibration of Mastcam-Z, but the broadband color filters are less reliable than the scientific narrowband filters, and specific filters occasionally yield anomalous reflectance data. After landing, many of materials Mastcam-Z will image will have dust coatings and/or weathering rinds, but the spectral and photometric properties of coated materials is relatively understudied. Given the ubiquity of ferric dust and basaltic sand on Mars, basaltic sand coated in ferric material will likely be encountered by Mastcam-Z, but no photometric studies of ferric coatings on sand grains have been previously reported. This study simulates such coatings by adhering pure nanohematite to a Mars-analog basalt sand and comparing the spectra of coated and uncoated sands over a suite of viewing geometries. The addition of a nanohematite coating has the largest effect on the visible wavelength ranges (~380 to 750 nm) particularly in the ultraviolet and violet range (~400 nm) where nanohematite has a strong absorption feature. Above about 1000 nm, the spectra of the coated and uncoated sands are nearly identical, even where the spectrum of nanohematite deviates from the spectrum of the substrate sand. Collectively, these results help validate Mastcam-Z and prepare for its observations of coated sands and other geologic materials on the surface of Mars when Perseverance lands.

Type

Text

Keywords

Mastcam-Z, spectroscopy, photometry, calibration, Mars, analog, calibration, coating, ferric

Publisher

Western Washington University

OCLC Number

1241212588

Subject – LCSH

Mars probes; Roving vehicles (Astronautics); Photometry; Stereoscopic cameras

Geographic Coverage

Mars (Planet)--Geology

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

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