This time-exposure picture of the asteroid Gaspra and background stars is one of four optical navigation images made by Galileo's imaging system to improve knowledge of Gaspra's location for the spacecraft flyby.
The 26-second exposure was made October 13, 1991, when Galileo was about 11 million kilometers (7 million miles) from the asteroid. The camera was deliberately slewed about 0.14 degrees to stretch the asteroid and star images into streaks. Information from this and other navigation images was used to design trajectory correction maneuvers to place the spacecraft in the best path for its observations of Gaspra. Image Credit: NASA/JPL