Today in the history of astronomy, the first spacecraft to orbit another planet begins to circle Mars.

| Published: November 13, 2026

When Mariner 9 arrived at Mars, it found the world obscured by a massive dust storm. Once the storm cleared, the spacecraft began the process of mapping the Red Planet. Credit: NASA/JPL

On May 30, 1971, Mariner 9 launched, setting off on its mission to Mars . On Nov. 13, 167 days later, it entered orbit around Mars, making it the first spacecraft to orbit another planet .

With Mariner 8, Mariner 9 was one half of the Mars 71 mission. But when Mariner 8 launched on May 9, it failed to achieve orbit and tumbled out of the sky after five minutes, crashing into the Atlantic Ocean.…