This photo of Jupiter's satellite Io was taken by NASA's Voyager 1 about 4:30 p.m. (PST) March 2, 1979. The spacecraft was about 5 million miles (8.3 million kilometers away).

This photo of Jupiter's satellite Io was taken by Voyager 1 about 4:30 p.m. (PST) March 2, 1979. The spacecraft was about 5 million miles (8.3 million kilometers away). Voyager 1 was mapping Jupiter with the cameras and infrared instrument at the time the picture was taken. The hemisphere seen here is the one that always faces away from Jupiter. This photo shows details on Io never before seen. The smallest features are about 38 miles (70 kilometers) across. Near the center and slightly to the right can be seen several round features with dark centers and bright rims. They may be the first craters ever observed on Io. At this resolution scientists still cannot tell much about the origin of the features, which could be impact craters or of internal (volcanic) origin. No ray or ejecta patterns are obvious at this resolution.

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