در این روز در فضا! 1 سپتامبر 1979: کاوشگر پایونیر 11 ناسا اولین فضاپیمایی شد که از زحل بازدید کرد.

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. Here's why it mattered.