Launched in 1972 and weighing 258 kilograms (569 pounds), Pioneer 10 completed the first mission to the planet Jupiter and became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System.

Pioneer 11 detected Saturn’s bow shock on Aug. 31, 1979, about 932,000 miles (1.5 million kilometers) out from the planet, thus providing the first conclusive evidence of the existence of Saturn’s magnetic field.