Source: Galileo

Information: This image is the first full picture showing both asteroid 243 Ida and its moon, to be transmitted to Earth from NASA's Galileo spacecraft -- the first conclusive evidence that natural satellites of asteroids exist. Ida is the large object to the left, about 56 kilometers (35 miles) long. Ida's natural satellite is the small object to the right. This portrait was taken by Galileo's charge-coupled device (CCD) camera on August 28, 1993, about 14 minutes before the spacecraft's closest approach to the asteroid, from a range of 10,870 kilometers (6,755 miles). Ida is a heavily cratered, irregularly shaped asteroid in the main asteroid belt between Mars and Jupiter -- the 243rd asteroid to be discovered since the first one was found at the beginning of the 19th century. It is a member of a group of asteroids called the Koronis family. The small satellite is about 1.5 kilometers (1 mile) across in this view. Although the satellite appears to be "next" to Ida it is actually slightly in the foreground, closer to the spacecraft than Ida. Combining this image with data from Galileo's near-infrared mapping spectrometer, the science team estimates that the object is about 100 kilometers (60 miles) away from the center of Ida. This image is one of a six-frame series taken through different color filters, this one in green. The spatial resolution in this image is about 100 meters (330 feet) per pixel. The Galileo spacecraft flew past Ida en route to its final destination, Jupiter.