On this day in space! Sept. 1, 1979: NASA's Pioneer 11 probe becomes 1st spacecraft to visit Saturn

On Sept. 1, 1979, NASA's robotic space probe Pioneer 11 became the first spacecraft to fly by Saturn.

Pioneer 11 launched in 1973 on a mission to explore the asteroid belt, Jupiter and Saturn. It launched directly toward Jupiter, then used Jupiter's gravity to slingshot around the planet, make a sharp turn and start flying toward Saturn. Four years and nine months later, it finally made it to Saturn.

During its closest approach, it was about 13,000 miles (2,100 kilometers) above the planet's cloud tops. Because NASA's two Voyager probes were also on their way to Sat...