Phoenix Landing Site Hazard Assessment and Selection

摘要

The Phoenix Mars Scout landing site hazard assessment and selection process began with a survey of the latitudenband from 65–72u0001N to identify candidate landing regions that were accessible, safe, and suitable for meeting thenmission science objectives. Four candidate landing regions were identified based upon proximity of ground ice to thensurface. Thermal inertia data, visible imagery, and topographic maps were combined to make an initial assessment ofnrock abundance and slopes. Broadly distributed high-resolution images enabled refined interpretation of the lowerresolutionndata sets. Based upon this assessment, a broad valley to the west of Heimdall crater at 68.3u0001N, 124.6u0001Wwasnselected as the target landing region for the Phoenix mission. A detailed evaluation of this region resulted in thenidentification of eight different geologic units, with each unit exhibiting characteristic terrain type and rocknabundances. Targeted high-resolution images were acquired across much of the region. An autonomous rockcountingnalgorithm was used to develop probabilistic risk distributions. Landing ellipse placement was selected tonmaximize the probability of a safe landing considering rock and slope hazards, including craters. Postlanding imagesnfrom the Phoenix stereoscopic imager show a landing site generally devoid of hazardous rocks and slopes, consistentnwith predictions.