Viking 1, an unmanned U.S. planetary probe, is launched from Cape Canaveral, Florida, on a mission to Mars.

On June 19, 1976, the spacecraft entered into orbit around Mars and devoted the next month to imaging the Martian surface with the purpose of finding an appropriate landing site for its lander. On July 20–the seventh anniversary of the Apollo 11 lunar landing–the Viking 1 lander separated from the orbiter and touched down on the Chryse Planitia region, becoming the first spacecraft to successfully land on the surface of Mars. The same day, the craft sent back the first close-up photographs of the rust-colored Martian surface.

In September 1976, Viking 2–launched only three weeks after Viking 1–entered into orbit around Mars, where it assisted Viking 1 in imaging the surface and also sent down a lander. During the dual Viking missions, the two orbiters imaged the entire surface of Mars at a resolution of 150 to 300 meters, and the two landers sent back more than 1,400 images of the planet’s surface.