Original Caption Released with Image:
These four images of the Moon are from data acquired by the Galileo spacecraft's Near-Earth
Mapping Spectrometer during Galileo's December 1992 Earth/Moon flyby. The part of the Moon
visible from Earth is toward the left, and the lunar north pole is near the terminator, upper right.
The dark regions to left and below in the black- and-white image at upper left, are lunar Maria,
including Mare Imbrium at upper left, Serenitatis and Tranquillitatis, lower left center, and the
circular basin to the right is Crisium. The bright areas ringing Crisium and dominating the center
of the images are the heavily cratered and mountainous lunar highlands. The black-and-white
image used infrared wavelengths just beyond the visible deep red. The false-color map images
(upper right and lower right) show the relative strength of silicate-rock absorption of
near-infrared sunlight, at about 1-micron wavelength. Blue areas show stronger absorption and
generally indicate materials with more pyroxene and olivine (iron-bearing silicate materials),
while yellow indicates less absorption, due to original compositional variations. In young fresh
craters, absorptions are also stronger due to the absence of meteorite-impact effects. Outlines of
previously defined geological units are superimposed in the lower right image. Note correlation
with the Maria/highlands features in the black-and-white image. The preliminary mineralogical
map at lower left uses infrared band shape and intensity to visualize variations in pyroxene and
olivine. Blue is related to low- calcium pyroxene, while green and red indicate high calcium and
the iron/magnesium content of pyroxene, as well as olivine. The Galileo project, whose primary
mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of
Space Science and Applications by the Jet Propulsion Laboratory.
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