NASA’s Pioneer 10 became the first spacecraft to fly through the asteroid belt and visit Jupiter.
Pioneer 10 launched on March 3, 1972, beginning the first mission to the outer solar system. Crossing the asteroid belt was a major engineering challenge because mission planners did not know how hazardous the region might be for a spacecraft. Pioneer 10 passed through successfully.
It made its closest approach to Jupiter on December 4, 1973. The spacecraft returned the first close-up images of Jupiter and gathered important measurements of the planet’s magnetic field, radiation environment, and atmosphere. Its observations helped engineers design later missions to the outer planets.
Pioneer 10 continued sending signals far beyond Jupiter. NASA received its last telemetry signal in January 2003, although a final very weak tracking signal was detected in 2006. Pioneer 11 followed its route and later visited Saturn.