On this day in 1991, NASA’s Galileo spacecraft flew by asteroid Gaspra, which is located in the asteroid belt between Mars and Jupiter. Galileo conducted a quick fly-by while flying towards Jupiter and its moons. The spacecraft also visited the asteroid Ida.
Asteroid Gasprawas first discovered back in 1916 by Russian astronomer G. N. Neujmin, who decided to name it after the Black Sea retreat of Gaspra, a Ukrainian spa town currently occupied by the Russians.
Here is some additional information from NASA about the asteroid, which has similar features to the asteroids now serving as moons to Mars (Phobos and Deimos):
A striking feature of Gaspra’s surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra’s very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars’s moon Phobos, but were predicted for asteroids as well.
You car read more about the overall Galileo mission here.