NASA’s Viking 1 lander made the first successful landing on Mars during the 1976 U.S. Bicentennial.
Viking 1 launched from Cape Canaveral on August 20, 1975, and reached Mars after an 11-month journey. Its orbiter entered Martian orbit on June 19, 1976. NASA originally planned the landing for July 4, the U.S. Bicentennial, but photographs showed that the first selected site was too rough for a safe touchdown.
The lander instead touched down on July 20, 1976, in Chryse Planitia. That date was also the seventh anniversary of Apollo 11’s Moon landing. Viking 1 transmitted the first images from the Martian surface and carried instruments to study the atmosphere, soil, weather, and possible signs of life.
Viking 2 followed with a successful Mars landing on September 3, 1976. The pair are often confused because both belonged to NASA’s Viking program, but Viking 1 arrived first and became the program’s historic initial landing success.