In 1977, twin spacecraft, Voyager 1 and 2, were launched to explore the outer solar system, Jupiter, Saturn, Uranus, and Neptune. The craft, Voyager 2 in particular, returned iconic, textbook images of the four planets and their retinue of moons. Fundamental discoveries were made: An ocean of undersea ice on Jupiter’s Moon Europa, and active volcanism on Jupiter’s moon Io; An orange moon of Saturn, Titan, with a thick atmosphere; a great dark storm in Neptune’s atmosphere, and sooty geysers erup