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Dactyl (click to enlarge)

Date: 28 Aug 1993

This image is the most detailed picture of Dactyl, a natual satellite (moon) of asteroid 243 Ida. Dactyl was the first moon found orbiting an asteroid. NASA's Galileo spacecraft discovered the tiny moon during a 1993 flyby of Ida while en route to Jupiter.

This frame captured the previously unknown moon at a range of about 3,900 kilometers (2,400 miles), just over 4 minutes before the spacecraft's closest approach to Ida.

More than a dozen craters larger than 80 meters (250 feet) in diameter are clearly evident, indicating that the moon has suffered numerous collisions from smaller solar system debris during its history. The larger crater on the terminator is about 300 meters (1000 feet) across. The satellite is approximately egg-shaped, measuring about 1.2 x 1.4 x 1.6 kilometers (0.75 x 0.87 x 1 mile). The Galileo project, whose primary mission was the exploration of the Jupiter system, is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

Image Credit: NASA, Jet Propulsion Laboratory

Credit: Lunar and Planetary Institute

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