We live in a golden age of solar system exploration. As of the start of 2013, we have flown by all of the planets out to Neptune and we're on our way to Pluto. We are exploring Mars with two rovers and the latest in a fleet of orbiters. We have spacecraft studying the Sun at the heart of the Solar System and the outskirts where interstellar space begins. We are in orbit around Mercury, flying to a dwarf planet in the asteroid belt, and continuing an extensive tour of Saturn and its moons. Many missions are cooperative endeavors with the space agencies of other nations.