Outward bound to the stars.
In this artist view of Pioneer 10, launched from Earth in 1972, the spacecraft makes a close passage of the Moon as it follows a path toward the giant planet Jupiter. The blue, cloud-covered Earth is in the background. This view shows the Moon's heavily cratered far side, highlighted by the dark crater Tsiolkovsky. Pioneer 10 will never return. After its encounter with Jupiter in 1973, Pioneer 10 was moving fast enough to escape from the solar system entirely. It is the first human artifact sent out to roam among the stars, a calling card announcing our existence to any other intelligences in the universe.