The first spacecraft to leave the inner solar system sailed into the asteroid belt 45 years ago today, 15 July 1972, on a mission that would mark many “firsts” for NASA’s exploration of the solar system. Pioneer 10, the first outer solar system mission, became the first probe not only to leave the inner solar system, but also the first probe to be launched on an escape trajectory from the solar system and the first craft to visit the planet Jupiter. Today, NASA’s Juno spacecraft continues the exploration efforts of the Giant Planet begun by Pioneer 10 over four decades ago.
