Pioneer 10 and 11 are the most famous probes in the Pioneer program, the first probes to visit the outer planets, and the first to go beyond the orbit of Pluto.

Pioneer 10 was the first spacecraft to travel through the asteroid belt, and was the first spacecraft to make direct observations of Jupiter. After more than 30 years, Pioneer 10 spacecraft has sent its last signal to Earth on Jan. 22, 2003. Pioneer 10 is heading in the direction of the star Aldebaran in the constellation Taurus.

Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. Last communication with Pioneer 11 was in November 1995.