Preparing to Scout the Next Frontier: Calibrating the Lunar Reconnaissance Orbiter Camera

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) and Narrow Angle Cameras (NACs) will be flown on the NASA Lunar Reconnaissance Orbiter (LRO). The WAC is a 7-color (5 visible, 2 UV bands) framing camera, while the 2 NACs are monochrome narrow-angle linescan imagers (0.5m/pixel). The primary mission of LRO is to obtain measurements of the Moon that will enable future lunar human exploration. The science goals of the LROC investigation include landing site identification and certification, mapping of permanently polar shadowed and sunlit regions, meter-scale mapping of polar regions, global multispectral imaging, a global morphology base map, characterization of regolith properties, and determination of current impact hazards. The instruments will be calibrated to 1% relative and 10% absolute accuracy prior and during flight, in order to meet mission objectives and facilitate comparisons between LRO mission instruments and instruments on previous or concurrent spacecraft. A comprehensive LROC calibration plan is in place, and includes (1) laboratory system-level testing to determine parameters such as the CCD gain and optics performance using radiometric sources, such as an integrating sphere, a monochromator, and geologic materials illuminated by calibrated external light sources. (2) Spacecraft-level testing to determine instrument geometry relative to LRO. (3) In-flight calibration to assess instrument performance and facilitate dataset production, such as repeat imaging of standard lunar regions (e.g., the Apollo 16 landing site).