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Gaspra - Galileo
| title |
Gaspra - Galileo |
| date |
10.29.1991 |
| description |
The Galileo spacecraft captured this view of asteroid 951 Gaspra in 1991. It was the first time a spacecraft made a close flyby of an asteroid. This image is a combination of images taken with the violet, green and near-IR filters at a resolution of about 163 m/pixel overlain on a 54 m/pixel resolution clear filter image. The colors are highly exaggerated to bring out subtle differences in surface properties. Bluish regions represent fresher rock, while reddish regions are composed of regolith materials. Gaspra is an irregular shaped body about 19 x 12 x 11 km. The illuminated portion in this image is about 18 km from lower left to upper right. The sun is shinning from the right. *Image Credit*: NASA |
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Gaspra - Highest Resolution
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| title |
Gaspra - Highest Resolution Mosaic |
| date |
10.29.1991 |
| description |
This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5,300 kilometers (3,300 miles), some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right, phase angle is 50 degrees. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. 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. The north pole is located at upper left, Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers (3.7 miles) across, the prominent crater on the terminator, center left, about 1.5 kilometers (1 mile). A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars's moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. 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. *Image Credit*: JPL |
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Asteroid Gaspra
| title |
Asteroid Gaspra |
| date |
10.29.1991 |
| description |
This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5300 kilometers, some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right, phase angle is 500. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. Gaspra is an irregular body with dimensions about 19 x 12 x 11 kilometers. The portion illuminated in this view is about 18 kilometers from lower left to upper right. The north pole is located at upper left, Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers across. The prominent crater on the terminator, center left, is about 1.5 kilometers. A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100 to 500 meters in diameter, are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size (such as the satellites of Mars). Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features believed to be related to fractures. These linear depressions, 100 to 300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, with one group wider and more pitted than the other. Grooves had previously been seen only on Mars' moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. The Galileo project, whose primary mission was the exploration of the Jupiter system, was managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. *Image Credit*: U.S. Geological Survey |
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