Pioneer 10:
Goals: Pioneer 10 was the first spacecraft intended to fly by Jupiter, surviving the intense radiation that surrounds the giant planet and then on a trajectory that would take it out of the Solar System.

Accomplishments: The spacecraft became the first to fly beyond Mars' orbit, through the asteroid belt, and close to Jupiter, blazing a trail for the two Voyager spacecraft that were to follow and conduct more in-depth surveys. Long before and after flying by Jupiter, Pioneer 10 transmitted data on the magnetic fields, energetic particle radiation and dust populations in interplanetary space. As it passed through the Jupiter system, it transmitted hundreds of photos of the planet and its moons, along with measurements of the Jovian atmosphere.

Tracking Pioneer 10 and its twin, Pioneer 11 as they speed away from the Sun has revealed an anomaly: each year, they travel about 5000 km less than scientists calculate that they should. If an explanation is found, it may alter our understanding of the two spacecraft, the way they are tracked, the Solar System environment or-unlikely but possible-our understanding of gravitation or other aspects of physics.

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2 Mar 1972:  Launch 13 Jun 1983:  Passed Orbit of Most Distant Planet Status:  Successful Show All Dates for Pioneer 10		25 Feb 2003:  Farewell Pioneer 10 20 Feb 2003:  Pioneer 10 Contacted 17 Dec 2002:  Pioneer 10 Contacted 23 Jul 2002:  Pioneer 10 Contacted More Headlines
Pioneer 10 was the first spacecraft to fly through the asteroid belt, first to fly close to Jupiterand first to cross Neptune's orbit on a course to leave our solar system. It carries a plaque with information about Earth and humans (above). Pioneer 10 was the farthest human-made object in existence until 17 February 1998, when Voyager 1 exceeded its range.		Solar System Bodies: Jupiter Pioneer 10 Multimedia Gallery NSSDC Master Catalog: Pioneer 10 NASA Ames Pioneer 10 and 11 History NASA History Office: Pioneer Odyssey