First Encounter
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October 29, 2011 The asteroid Gaspra looms in the sights of the Galileo spacecraft in this 1991 image. Gaspra was the first asteroid ever visited by a spacecraft, with Galileo passing just a few thousand miles from the rocky body en route to Jupiter. Gaspra has an average diameter of about seven miles, and is marked by impact craters and long cracks that suggest Gaspra was once part of a larger body. [NASA/JPL]
