Pioneer 10, launched on March 2, 1972, was the first spacecraft to pass through the asteroid belt (which some scientists thought would be impossible), the first to make direct observations and obtain close-up images of Jupiter and the first human-made object to pass the orbit of Pluto. At last contact, Pioneer 10 was 82 AU’s (astronomical units–the nominal distance between the Sun and the Earth) away–approximately twice as far as the orbit of Pluto. At that distance, it takes more than 11 hours and 20 minutes for its radio signals to reach the Earth.

Pioneer 10 is also Earth’s first emissary, carrying a gold-anodized aluminum plate, which was designed by Carl Sagan and Frank Drake and drawn by Linda Salzman Sagan. This plate was attached to the antenna support struts of the spacecraft so as to be shielded from erosion by interstellar dust. It describes what we look like, where we are, and the date when the mission began. The late Dr. Sagan, discussed the significance of the plaque in this video interview.

Pioneer 10 will continue to coast silently through interstellar space, heading generally towards the red star Aldebaran, 68 light-years away in the constellation Taurus. It will take Pioneer 10 more than two million years to reach it.