How to Colonize an Asteroid
Specific Asteroids: 951 Gaspra

951 Gaspra

Size: 19 X 12 X 11 km
Type: Class S
Discovered: 1916 by Grigoriy Neujmin
Image taken by: Galileo Probe
Date: October 29, 1991
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109.  TELEPHONE (818) 354-5011

PHOTO CAPTION                                     GALILEO
June 11, 1992                                     P-40450-C
                              TOP                 GLL/GA5

This picture of asteroid 951 Gaspra is a combination of the
highest-resolution morphology and color information obtained by
the Galileo spacecraft during its approach to the asteroid on
October 29, 1991.  The Sun is shining from the right; phase angle
is 50 degrees.  The base image is the best black-and-white view
of Gaspra (resolution 54 meters/pixel) on which are superimposed
the subtle color variations constructed from violet, green, and
near-infrared (1000 nanometers) inages taken in an earlier
sequence at a resolution about 164 meters per pixel.  The very
subtle color variations on Gaspa's surface have been artificially
exaggerated here; to first order Gaspra's color is fairly
homogeneous over the surface.  However, subtle albedo and color
variations do occur and are correlated with surface topography in
a significant way.  In this false-color view, the bluish areas
represent regions of slightly higher albedo, which are also
regions of slightly stronger spectral absorption near 1000
nanometers, probably due to the mineral olivine.  These bluish
areas tend to be associated with some of the crisper craters and
with ridgeÿs.  The slightly reddish areas, apparently concentrated
in topographic lows, represent regions of somewhat lower albedo
and weaker absorption near 1000 nanometers.  In general, such
patterns can be explained in terms of greater exposure of fresher
rock in the brighter bluish areas and the accumulation of some
regolith materials in the darker reddish areas.  Gaspra is an
irregular body with dimensions about 19 x 12 x 11 kilometers (12
x 7.5 x 7 miles).  The portion illuminated in this view is about
18 kilometers (11 miles) from lower left to upper right.  This
color picture results from a joint effort by image processing
groups at the U. S. Geological Survey in Flagstaff, Arizona,
Cornell University in Ithaca, New York, and JPL.  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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