The Mariner 4 mission to Mars was conducted by the Jet Propulsion Laboratory (JPL) of the National Aeronautics and Space Administration (NASA) in 1965. It was the first successful mission to the red planet, and it made a number of groundbreaking discoveries.

The mission was designed to photograph the surface of Mars and to collect data on its atmosphere, temperature, and pressure. Mariner 4 was launched from Cape Canaveral, Florida, on November 28, 1964. The spacecraft traveled for nearly eight and a half months before finally reaching Mars on July 14, 1965.

Mariner 4 flew by the planet at a distance of about 6,200 miles (10,000 km). During its 20-minute flyby, the spacecraft sent back 22 black-and-white images of the Martian surface. These images showed a barren, cratered landscape, looking very much like the moon. This was a huge surprise to scientists, who had expected to see a lush, green world.

The data that Mariner 4 collected also gave scientists a better understanding of the atmosphere and environment of Mars. They discovered that the atmosphere was mostly composed of carbon dioxide, with some nitrogen and argon. They also found that the atmospheric pressure was much lower than on Earth, and the temperature was much colder.

Perhaps the most important discovery made by Mariner 4 was the discovery of the Mariner Valley. This deep canyon on the surface of Mars, which is over 3,000 miles (4,800 km) long and up to 6 miles (10 km) deep, was named after the mission.

The Mariner 4 mission was a huge success for NASA and the JPL. It was the first successful mission to Mars, and it laid the foundation for future explorations of the planet. Since 1965, numerous other space probes have been sent to Mars, including the Viking landers, the Mars Pathfinder rover, and the Curiosity rover. Each mission has made further groundbreaking discoveries about the red planet.

The Mariner 4 mission was a huge step forward for space exploration and the understanding of Mars. It is a milestone in NASA’s exploration of the red planet.