Radiometric Calibration Targets for the Mastcam-Z Camera on the Mars 2020 Rover Mission

Abstract

The Mastcam-Z Camera is a stereoscopic, multispectral camera with zoom capability on NASA’s Mars-2020 Perseverance rover. The Mastcam-Z relies on a set of two deck-mounted radiometric calibration targets to validate camera performance and to provide an instantaneous estimate of local irradiance and allow conversion of image data to units of reflectance (R∗ or I/F) on a tactical timescale. Here, we describe the heritage, design, and optical characterization of these targets and discuss their use during rover operations. The Mastcam-Z primary calibration target inherits features of camera calibration targets on the Mars Exploration Rovers, Phoenix and Mars Science Laboratory missions. This target will be regularly imaged during flight to accompany multispectral observations of the martian surface. The primary target consists of a gold-plated aluminum base, eight strong hollow-cylinder Sm2Co17 alloy permanent magnets mounted in the base, eight ceramic color and grayscale patches mounted over the magnets, four concentric, ceramic grayscale rings and a central aluminum shadow post (gnomon) painted with an IR-black paint. The magnets are expected to keep the central area of each patch relatively free of Martian aeolian dust. The Mastcam-Z secondary calibration target is a simple angled aluminum shelf carrying seven vertically mounted ceramic color and grayscale chips and seven identical, but horizontally mounted ceramic chips. The secondary target is intended to augment and validate the calibration-related information derived from the primary target. The Mastcam-Z radiometric calibration targets are critically important to achieving Mastcam-Z science objectives for spectroscopy and photometric properties.

The SHERLOC Calibration Target on the Mars 2020 Perseverance Rover: Design, Operations, Outreach, and Future Human Exploration Functions

“…SHERLOC operates on the arm and-while the instrument was designed to maintain alignment and performance in the martian environment-the daily thermal cycles, aeolian dust, and percussion/drilling operations require periodic assessment of alignment, calibration, and performance of the instrument to obtain the most accurate data being measured. The calibration targets employed on spaceflight instruments serve a vital function ensuring instrument performance can be assessed, as needed, over the course of the mission, as instruments experience degraded abilities due to routine aging (e.g., Barnes et al 2011;Campbell et al 2014;Helbert et al 2014;Kinch et al 2020;Yingst et al 2020). Calibration targets also have a rich history of supplementary use for ancillary science functions and education and public outreach.…”

Appraisal of Low-Cost Pushbroom Hyper-Spectral Sensor Systems for Material Classification in Reflectance

“…The MastcamZ instrument on the Mars 2020 rover is planned to provide unprecedented multispectral imagery of the Red Planet's surface [63,64]. The MastcamZ instrument possesses similar sensitivity to the VIS/NIR wavelengths studied in this work, though these wavelengths have been traditionally favored for vegetation analysis [2,4,24].…”

“…The MastcamZ instrument possesses similar sensitivity to the VIS/NIR wavelengths studied in this work, though these wavelengths have been traditionally favored for vegetation analysis [2,4,24]. The MastcamZ, as with many cameras flown to Mars, was calibrated using materials of a known radiance comprising a target that is being carried on board Mars 2020 [64]. Results returned from the sensors tested here will be compared with those returned from comparable minerals identified by MastcamZ at Jezero Crater.…”

The Ground-Based BIOMEX Experiment Verification Tests for Life Detection on Mars

“…Considering that few works have dealt with the interactions of incident UV flux with minerals and rocks [9,[21][22][23], even in preparation for in situ missions to Mars (such as ExoMars and Mars 2020 [24,25]), the issue is not yet well understood, and therefore a further necessary step is to identify the extent to which rocks and minerals can provide effective shielding against UV radiation.…”