Pioneer 10 & 11
Pioneer 10 and 11 were NASA's first missions to the outer planets - groundbreaking explorers that gave humanity its first close-up views of Jupiter and Saturn. Pioneer 10 was the first spacecraft to leave the inner solar system and the most distant human object until Voyager 1 passed it in 1998.
Firsts in Space Exploration
The Pioneer missions achieved numerous space exploration firsts: first spacecraft to travel through the asteroid belt, first to visit Jupiter, first to visit Saturn, and the first to leave the solar system. They paved the way for Voyager and remain milestones of human achievement.
Pioneer 10 - Jupiter
Pioneer 10 launched on March 2, 1972 and reached Jupiter in December 1973, passing within 200,000 km of the planet's cloud tops. It sent back the first close-up images of Jupiter, revealing its Great Red Spot and atmospheric bands in unprecedented detail.
Pioneer 11 - Saturn
Pioneer 11 used Jupiter's gravity as a slingshot to reach Saturn, arriving in September 1979. It discovered two new moons (Epimetheus and Janus) and a new ring segment. The spacecraft's trajectory required a precise path through Saturn's rings - setting up Voyager's later visit.
Pioneer Plaque
Both spacecraft carry the famous Pioneer plaque - a 6x9 inch gold anodized aluminum plaque showing human figures, the spacecraft's trajectory, and Earth's location in the galaxy. Designed by Carl Sagan and Frank Drake, it was humanity's first message intended for possible extraterrestrial intelligence.
Current Status
Pioneer 10's last signal was received in 2003 when it was 12 billion km from Earth. Pioneer 11's last signal was in 1995. Both spacecraft continue traveling toward interstellar space, but their radio transmitters are no longer powered. Pioneer 10 is heading in the general direction of the Aldebaran star system in Taurus.
Communication
At Jupiter distances, Pioneer 10's 2.7-meter dish antenna transmitted at 8 watts with a data rate of 256 bits/sec. By comparison, Voyager's much more sophisticated system achieves similar performance at 10x the distance.
Illustrations
