What is LROC: Objectives

1. Surface characterization of potential landing sites. LROC will provide images of meter and smaller-scale features that pose a potential threat to landing and obstacles to trafficability. An accurate assessment of the surface characteristics requires 0.5 m/pixel resolution in order to unambiguously identify meter-size objects. In addition, when the Sun is only 10° to 30° above the horizon, features less than 0.5 m high can be identified by their long shadows. The LROC NAC will detect blocks with ~1m horizontal scale and heights less than 0.5 m.

2. Mapping of permanently shadowed and sunlit regions. The spin axis of the Moon is tilted by only 1.5° (compared with the Earth's 28.5), potentially leaving some areas near the pole in permanent shadow while allowing others parts in remain in permanent, or near-permanent, illumination. Theory, radar data, and neutron measurements suggest that ice may be present in these permanently shadowed regions. In addition, areas of permanent, or near- permanent, illumination are prime locations for future lunar outposts due to benign thermal conditions and constant solar-power. During each orbit around the Moon, the LROC Wide Angle Camera (WAC) will acquire images at 100 meter per pixel of the polar regions (80° to 90° north and south latitude). A movie of compiled WAC polar images will graphically illustrate regions of permanent shadow and permanent, or near-permanent, illumination.

3. Meter-scale mapping of polar regions with continuous illumination. During respective summers (although less intense, the Moon has seasons like th Earth), the NAC will acquire meter-scale images of both polar regions (above 85.5 latitude) when shadows re minimal. Images collected during the summar will be compiled into 1 m/pixel regional mosaics (one for each pole). These high-resolution mosaics will provide a basemap for planning future polar exploration.

4. Overlapping observations to enable derivation of meter-scale topography. The LROC NAC will collect stereo images that can be used to provide detailed topographic maps of important areas.

5. Global multispectral imaging to map ilmenite and other minerals. Seven filters within the LROC WAC will allow scientists to identify concentrations ilmenite, olivine, and other minerals in the lunar regolith. Understanding the distribution of the economically important mineral ilmenite, in particular, is vital for understanding the distribution of accessible resources on the lunar surface.

6. Global morphology base map. The LROC WAC will provide 100 meter per pixel images with Sun angles optimal for morphological mapping (the Sun 15° to 35° above the horizon) , except in polar regions where the Sun is always very low on the horizon. The WAC global map will improve efforts to characterize terrains based on crater counts, especially on the far side of the Moon where existing images from earlier missions have high Sun and poor resolution.

7. Characterize regolith properties. The LROC NAC high-resolution images will give scientists extremely detailed views of the regolith (soil) Depending on regolith thickness, different sizes of craters have distinctive interior shapes. Mapping the frequency and distribution of these crater mophologies will provide accurate estimates of regolith thickness around potential lunar landing sites.

8. Determine current impact hazards. The LROC NAC will rephotograph areas seen in Apollo photography so that impact new craters can be identified. At Mars, about 70 craters have been found that formed since the late 1970s when the Viking mission was active at Mars. Cataloging craters formed since Apollo provides a count of the number of small asteroids and comets that have impacted the Moon in the past 40 years, information critical to assessing the rate at which impact craters form and mitigating the hazards to future human spacefarers.