951 Gaspra


An image of Gaspra captured by the Galileo spacecraft, when it flew by the asteroid on its way to Jupiter on 29 October 1991. Credit: NASA.

951 Gaspra became the first asteroid to be seen close up when the Galileo spacecraft flew past it at a distance of 1,600 kilometers, on 29 October 1991, en route to Jupiter.


Gaspra is an S-type asteroid, a member of the Flora family, elongated and irregular in shape, and lacking any large craters, which suggests that it has a comparatively recent origin, most likely from the collisional breakup of a larger body some 300 to 500 million years ago. It was discovered by Grigoriy N. Neujamin in 1916 and named after a Russian resort and spa near Yalta, Crimea, that was visited by contemporaries such as Tolstoy and Gorky.


diameter 19 × 12 × 11 km
spectral class S
visual albedo 0.2
rotational period 7.04 hours
semimajor axis 2.209 AU
perihelion 1.828 AU
aphelion 2.592 AU
eccentricity 0.174 AU
inclination 4.10°
period 3.29 years