951 Gaspra: First pictures of an asteroid



On October 29, 1991, the Galileo spacecraft flew past 951 Gaspra at a distance of 1600 km and obtained the first close-up views of an asteroid. The best view of an asteroid ever taken (Figure 1) from some 5300 km out, shows detail as fine as 54 m.

Among the more than 5,000 numbered asteroids, 951 Gaspra is a relatively small, highly elongated object with an average radius of about 7 km, orbiting near the inner edge of the main asteroid belt (semimajor axis of 2.21 AU), in the so-called Flora region. This region is densely populated with small asteroids that are generally thought to be the fragments of one or more larger precursor asteroids smashed by catastrophic collisions.