HOW HIRISE CHANGED MARS EXPLORATION (Invited Presentation)

Images acquired by the High-Resolution Science Experiment (HiRISE) (Alfred McEwen, P.I.) have fundamentally changed Mars exploration. HiRISE images have enabled detailed investigation of rover traverse routes, key locations to visit, and to accurately characterize landing sites. Prior to HiRISE, navigation and localization of the Mars Exploration Rovers was approximate. After HiRISE, the 4.5 yr, 27 km traverse of Opportunity from Victoria to Endeavour crater was planned to successfully avoid untraversable eolian bedforms, visit impact craters in a variety of degradational states (many by “drive by shootings”), and accurately localize the rover after each drive. Prior to HiRISE, rocks on the surface of Mars could not be reliably detected or counted. About one year before the launch of the Phoenix lander, HiRISE images identified hazardous rock fields that eliminated most of the areas thought to be suitable for landing. Machine vision techniques were used to measure rock shadows (diameter and height), measure their size-frequency distribution, extrapolate to smaller diameter rock counts made from landers, and fit to exponential rock size-frequency models that have accurately predicted rock distributions at all subsequent landing sites. Nearly complete stereo HiRISE images of the Gale crater landing site for Mars Science Lander allowed Digital Elevation Maps with 1 m elevation postings, which for the first time allowed mapping possible traverse paths to high science priority science target in the central mound and to identify inescapable hazards (areas safe for landing, but not trafficable). Sparse HiRISE DEMs and complete coverage of the 130 km by 27 km InSight ellipse were used to create a hierarchically controlled DEM accurately referenced to the cartographic grid, tuned photoclinometry for a complete slope map across the ellipse, measure and map the thickness of a fragmented regolith, and discover, map and characterize secondaries from the very young, rayed crater Corinto. Complete stereo HiRISE coverage of the Jezero crater landing site for the Mars 2020 Rover and adjacent areas has allowed the creation of a hazard map (rocks, slopes, inescapable hazards) for safe landing, identification of high science targets for exploration by the rover and traverse maps within the ellipse and to neighboring areas.