Humans have traveled to the far corners of the solar system through the eyes of robotic explorers – spacecrafts, probes, and rovers that have sent back progressively more astonishing data and images. The colored lines illustrate nearly 200 unmanned missions since 1958: flybys, orbits, soft landings, and intentional crashes, as well as some of the failures. No human has left low Earth orbit since 1972, when Apollo 17 made the last of NASA's 9 manned missions to the moon. But odds are we will. A privately funded mission aims to have a man and a woman to circle Mars as early as 2018.