June 16, 2014
Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS)and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths:
575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Inner Rim of Rachmaninoff (lower left crater) is 140 km (87 mi.) in diameter
The top image is a MASCS
VIRS interpolated color composite
of the craters Rachmaninoff
(lower left) and Copland
(upper right). The bottom image is a monochrome MDIS mosaic of the same area. In the VIRS image, red areas like Copland (C) are brighter than blue areas like Rachmaninoff (R). The very bright red region in-between is a suspected volcanic vent
(V). The color differences revealed in the VIRS image reveal differences in the composition of the surface rocks, as well as varying degrees of exposure to space weathering
in the harsh environment of Mercury.
The VIRS composite shows hundreds of individual footprints tracks (minimum 100-200 m across and 3-4 km long) taken from different directions and altitudes. In locations where multiple footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map. In areas where footprints are sparse (separated by tens of km), observations are interpolated for complete coverage of the surface. In the MDIS mosaic, some brightness variations are due to tiling of images taken at different illuminations.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation
are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
For information regarding the use of MESSENGER images, see the image use policy.