The unmanned space probe Pioneer 11 is launched on a course that will be one of the first real tests of the theory of gravity assist. Reaching Jupiter in 1975, it will use the giant planet’s gravity to throw it across the solar system to rendezvous with Saturn, the first human-made vehicle to visit that planet. The experience gained with Pioneer 11’s groundbreaking trajectory through the solar system will prove instrumental in the upcoming Mariner Jupter/Saturn ’77 mission, which is later be renamed Voyager.
