Viking 1 was the first American spacecraft to land successfully on Mars.
NASA launched Viking 1 on August 20, 1975, as part of a paired orbiter-and-lander mission. Its lander touched down in Chryse Planitia on July 20, 1976, becoming the first U.S. spacecraft to make a successful soft landing on Mars. Viking 2 followed with its own landing in September 1976.
The Viking lander returned the first photographs from the Martian surface and conducted experiments on soil, atmosphere, weather, and possible biological activity. Its biology experiments produced results that were extensively studied, but they did not establish clear evidence of life.
The Viking 1 orbiter also mapped Mars and relayed communications between Earth and the lander. The mission's success marked a major advance over earlier Soviet attempts, including Mars 3, which achieved a landing but stopped transmitting after less than two minutes.