“Touchdown, we have touchdown!” At 5:12 a.m. PDT, July 20, 1976, mission controllers at NASA’s Jet Propulsion Laboratory erupted in cheers as they learned that the Viking 1 lander had survived its descent through the thin Martian atmosphere. Forty minutes later, the lander’s first image began to appear on their monitors, slowly forming line by line from left to right. For the first time, humans were able to see Mars’s rocky terrain from its surface.

Dr. Thomas Mutch, leader of the Viking lander imaging team, described the moment: “I studied the black screen, waiting for that narrow strip that will signal the first few lines of the first picture. And it appeared. A sliver of electronic magic. Areas of brightness and darkness. The picture begins to fill the screen. Rocks and sand are visible and — finally at the far right — one of the spacecraft foot pads, a symbolic artifact that stamps our accomplishment with the sign of reality. Time and time again I repeat, ‘It’s incredible.’”

Fifty years ago today, the Viking 1 lander became NASA’s first robot to explore Mars’s surface and begin the search for signs of life in our solar system. Viking 1 was joined six weeks later by its twin lander, Viking 2, which explored a different region of Mars, while two mission orbiters that delivered the landers to the Red Planet continued to collect data from space and helped relay communications to Earth.

Learn more about what Viking found and NASA’s legacy of discovery on Mars at Viking: 50 Years on Mars.

Image credit: NASA/JPL