The Mercury Dual Imaging System on the MESSENGER S

Authors: S Edward Hawkins John D Boldt Edward H Darlington Raymond Espiritu Robert E Gold Bruce Gotwols Matthew P Grey Christopher D Hash John R Hayes Steven E Jaskulek Charles J Kardian Mary R Keller Erick R Malaret Scott L Murchie Patricia K Murphy Keith Peacock Louise M Prockter R Alan Reiter Mark S Robinson Edward D Schaefer Richard G Shelton Raymond E Sterner Howard W Taylor Thomas R Watters Bruce D Williams

Publish Date: 2007/10/23

Volume: 131, Issue: 1-4, Pages: 247-338

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Abstract

The Mercury Dual Imaging System MDIS on the MESSENGER spacecraft will provide critical measurements tracing Mercury’s origin and evolution MDIS consists of a monochrome narrowangle camera NAC and a multispectral wideangle camera WAC The NAC is a 15° fieldofview FOV offaxis reflector coaligned with the WAC a fourelement refractor with a 105° FOV and 12color filter wheel The focal plane electronics of each camera are identical and use a 1024×1024 Atmel Thomson TH7888A chargecoupled device detector Only one camera operates at a time allowing them to share a common set of control electronics The NAC and the WAC are mounted on a pivoting platform that provides a 90° fieldofregard extending 40° sunward and 50° antisunward from the spacecraft +Zaxis—the boresight direction of most of MESSENGER’s instruments Onboard data compression provides capabilities for pixel binning remapping of 12bit data into 8 bits and lossless or lossy compression MDIS will acquire four main data sets at Mercury during three flybys and the twoMercurysolarday nominal mission a monochrome global image mosaic at nearzero emission angles and moderate incidence angles a stereocomplement map at offnadir geometry and nearidentical lighting multicolor images at low incidence angles and targeted highresolution images of key surface features These data will be used to construct a global image base map a digital terrain model global maps of color properties and mosaics of highresolution image strips Analysis of these data will provide information on Mercury’s impact history tectonic processes the composition and emplacement history of volcanic materials and the thickness distribution and compositional variations of crustal materials This paper summarizes MDIS’s science objectives and technical design including the common payload design of the MDIS data processing units as well as detailed results from ground and early flight calibrations and plans for Mercury image products to be generated from MDIS data

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