On what date did NASA’s Viking 1 lander touch down on Mars?

NASA’s Viking 1 lander touched down on Mars on July 20, 1976.

Viking 1 was part of NASA’s Viking program, which sent an orbiter and lander to Mars. The lander reached the surface in Chryse Planitia, a broad plain in the planet’s northern hemisphere. Its successful landing marked the beginning of a long and scientifically important surface mission.

After landing, Viking 1 photographed its surroundings, measured atmospheric and meteorological conditions, analyzed soil, and performed biology experiments designed to search for signs of microbial activity. The results did not provide accepted evidence of present or past life, although they helped establish important limits on Martian soil chemistry.

The date is sometimes confused with later Mars landings. NASA’s Pathfinder landed on July 4, 1997; Curiosity landed on August 6, 2012; and Perseverance landed on February 18, 2021. Viking 1 also predates the smaller, mobile rover missions: its lander remained stationary while its orbiter surveyed Mars from above.