Almost exactly a year after the Apollo lunar exploration program wound down, and smack-dab in the middle of the Watergate scandal, Pioneer 10 became the first spacecraft to encounter Jupiter, snapping this picture of the giant planet's icy moon, Europa. Pioneer 10 didn't even have a proper camera. Instead, as the spacecraft spun around, a light sensor scanned the face of Europa, building up this picture line by line at a crude resolution of 100 miles per pixel.