Viking 1 made the first fully successful Mars landing

NASA’s Viking 1 lander touched down on Chryse Planitia on July 20, 1976, becoming the first US spacecraft to land on another planet and the first lander to keep working on Mars, which it did for more than six years.

Wasn’t the Soviet Union first?

In one sense, yes. The Soviet Mars 3 touched down in December 1971, but contact ended for good less than 2 minutes after landing. Before Viking 1, it was the only mission ever to operate from the Martian surface. So Viking 1 was not the first craft to land on Mars, but it was the first to land and carry out its mission, and it gave the world its first clear look at the ground there.

The date was not the one NASA wanted. Managers had planned to land on July 4, the US bicentennial, but photos from orbit showed the chosen site was rougher than expected, and the hunt for a safer spot cost more than two weeks. The landing fell instead on the seventh anniversary of Apollo 11. Within five minutes, the lander was sending back its first picture: its own footpad on a plain of soil and rocks.

Viking 1 scooped soil for three biology experiments; they produced no definitive evidence of life. With its orbiter and the Viking 2 pair, it far outlived a planned 90-day mission. The two orbiters returned 52,663 images and mapped 97% of the planet, while the landers sent about 4,500 photos from the surface.

The Viking 1 lander kept reporting the weather until November 11, 1982, a run of 2,307 Earth days that stood as the Mars surface record until the Opportunity rover passed it in May 2010. After the two Vikings, no spacecraft landed on Mars again until Pathfinder on July 4, 1997, and in 2006 the Mars Reconnaissance Orbiter photographed the silent Viking 1 lander from orbit.