Astronomy Picture of the Day . ... The robot spacecraft Galileo whose primary mission is to explore the Jupiter system, has encountered and photographed two asteroids during its long journey to Jupiter. ... The Earth-Moon System . ... A double planet? From 4 million miles away on December 16, 1992, NASA's robot spacecraft Galileo took this picture of the Earth-moon system. ... This picture of the planet Jupiter was taken by the Voyager 1 spacecraft as it passed the planet in 1979. ...