Pioneer 10 is an American space probe, launched in 1972 and weighing 260 kilograms, that completed the first mission to the planet Jupiter. Thereafter, Pioneer 10 became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System. Voyager 1 is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Before Voyager 1 Pioneer 10 was the farthest m