March 31, 1997

This false color infrared composite of Jupiter's moon Io was produced from images
acquired in July and September, 1996, during the first two orbits through the
Jovian system by NASA's Galileo spacecraft. The area shown is 11,420
kilometers in width. Grid lines in this cylindrical map projection are superimposed
at latitude and longitude intervals of 30 degrees. Deposits of sulfur dioxide frost
appear in white and grey hues while yellowish and brownish hues are probably due
to other sulfurous materials. Bright red materials (such as the prominent ring
surrounding the currently erupting plume Pele) and spots with low brightness or
albedo ("black" spots) mark areas of recent volcanic activity and are usually
associated with high temperatures and surface changes (Voyager to Galileo or
Galileo to Galileo). The color map will be compared to other observations, such as
maps of topography and hot spots, to better understand the volcanic and surface
processes on this dynamic satellite.

The color in the image is composed of data taken in the near-infrared (756
nanometer), green and violet filters (shown as red, green, and blue respectively) of
the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. Images
were obtained at resolutions ranging from 10 to 23 kilometers per picture element
(pixel) and phase angles (spacecraft-Io-sun angle) from 4 to 55 degrees. The
spacecraft range varied from 485,000 to 2,243,000 kilometers. North is to the top
of the picture.

Launched in October 1989, Galileo entered orbit around Jupiter on December 7,
1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its
largest moons and the Jovian magnetic environment. The Jet Propulsion
Laboratory, Pasadena, CA manages the mission for NASA's Office of Space
Science, Washington, DC.

This image and other images and data received from Galileo are posted on the
World Wide Web, on the Galileo mission home page at URL Background information and educational context
for the images can be found at URL