April 10, 2012
Visible and Infrared Spectrograph (VIRS) of the MESSENGER Atmosphere and Surface Composition Spectrometer (MASCS)
This sinusoidal equal area projection map shows a color composite of Mercury spectral reflectance observed by the MASCS
VIRS instrument over the MESSENGER primary mission. VIRS footprint tracks are RGB-colored where red is brightness at 575 nm; green is the visible to infrared brightness ratio (415 nm / 750 nm); and blue is the ultraviolet to visible ratio (310 nm / 390 nm).
Broad regional differences and local areas of interest stand out with combinations of ratio and brightness values that give clues to mineralogical composition. Younger surface materials that are brighter at visible wavelengths and less affected by the processes of space weathering
show up in reds, yellows and greens. Materials that may have relatively higher iron contents (though still very low relative to most lunar or terrestrial crustal rocks) show up in blues.
In locations where multiple VIRS 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.
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. Visit the Why Mercury?
section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MESSENGER acquired over 1.8 million VIRS spectra and extensive other data sets. MESSENGER is now in a yearlong extended mission, during which plans call for the acquisition of more than 1.5 million additional spectra to support MESSENGER's science goals.
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.