AN INVESTIGATION OF INESCAPABLE HAZARDS AND TRAVERSABILITY OF MARS SCIENCE LABORATORY LANDING SITES

Selection of the Mars Science Laboratory (MSL) landing site required the analysis of surface characteristics, geology and safety of the four candidate landing sites. This included the identification and mapping of areas within each landing site that could potentially trap the rover after a safe landing, such as a crater or mesa, and traverse routes to access areas of scientific interest. Investigation of these sites was performed with visible imagery from the High Resolution Imaging Science Experiment (HiRISE at 0.3 m/pixel) and slope maps created from stereo-derived HiRISE Digital Elevation Models at 1 m resolution. The slope maps in conjunction with the visible imagery were used to identify potentially hazardous areas to the rover and 10 m wide paths the rover can drive along. Parameters for constraining traverse routes and inescapable hazards are that the MSL rover can drive up slopes <30° and <15° on outcrop and cohesion-less material, respectively and could drive down slopes <45°. Gale Crater, the selected site, was considered amongst the final 4 landing sites along with Eberswalde Crater, Holden Crater, and Mawrth Vallis. Each site had very small areas covered by inescapable hazards and was not a concern when selecting a site. Potential hazards covered <0.19% of Gale, compared to 0.28% in Holden 0.01% in Mawrth Vallis and 0.01% in Eberswalde. Mawrth Vallis has few traversability concerns. Eberswalde has rough and rocky terrain in the western part of the ellipse, but do not block access to the delta. Holden Crater has large eolian ripples that impede driving in troughs south of the ellipse, but phyllosilicate bearing layers could be accessed by driving on the plains above. At Gale Crater, a field of fresh, dark sand dunes extends from the southeastern to southern part of the landing ellipse. Slopes on many of the dunes exceeds 15°, but about 6 low slope paths exist through the dunes so that traversing from the ellipse to the mound should be possible. Multiple traversable paths have been identified that cross the key sulfate and clay layers identified in the lower part of the mound. Traversing above these layers higher into the mound dominated by more sulfate-rich layers will be more challenging, requiring driving on specific paths (~6 have been identified) with slopes that are up to 30°.