En route to Jupiter, the Galileo spacecraft is the first to fly close to asteroids. The first encounter is with asteroid Gaspra, passing it at a distance of 1600 kilometers (1000 miles).

Gaspra is believed to be composed of a mixture of rocky and metallic minerals. Rotating about its axis once in 7 hours, Galileo has ample opportunity to observe all its sides, finding that Gaspra is an irregular object
(19 by 12 by 11 kilometers), which lacks the large craters common on many planetary satellites.

See also: Galileo home page

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