Until the fall of 1959, humanity knew only one side of the Moon. The reason is that the Earth's natural satellite rotates on its axis in approximately the same time it takes to orbit the planet, and almost always shows the same half. This changed with the mission of the Soviet spacecraft Luna 3.
The spacecraft was launched on October 4, 1959 as part of the Soviet Union's lunar program. After flying behind the Moon on October 6, it found itself on the side that can never be directly observed from Earth. The next day, the photo session began.
29 frames from the far side
The first photo was taken at 03:30 Universal Time on October 7, 1959, when Luna 3 was about 63,500 kilometers from the lunar surface. Within approximately 40 minutes, the device took a total of 29 photos, covering about 70 percent of the far side. NASA data shows that the images were captured on 35 mm film, developed automatically on board, then scanned and transmitted to Earth by radio signal.
The quality of the frames is low by today's standards. Some of them are noisy and unclear, and only 17 were successfully obtained and allow for the recognition of individual details. However, the images provide the first real glimpse of a surface that had previously been the subject of speculation.
“This is the first time humanity has seen the far side of the Moon“, defines the historic image NASA Science.A landscape unlike any we've ever seen
The first images show that the far side of the Moon is not entirely unlike the half visible from Earth. It has many more impact craters and significantly fewer dark plains. These plains, called lunar maria, are formed by ancient flows of basaltic lava and are a characteristic part of the known lunar disk.
The difference between the two hemispheres is becoming an important scientific question. Images from Luna 3 show that the history of the lunar surface is more complex than observations from Earth suggest. Some of the newly discovered areas were given temporary names, including the Sea of Moscow, but later maps replaced some of the early designations.
Subsequent missions provide a clearer picture
In 1965, the Soviet spacecraft Zond 3 sent back better images and completed the picture of the far side. The first people to see it with their own eyes were astronauts Frank Borman, James Lovell, and William Anders during the Apollo 8 mission in December 1968.
Today, the far side has been photographed in detail by automated orbital missions. The beginning, however, was set by the grainy footage of Luna 3, which on October 7, 1959, turned the invisible half of the Moon into an observable scientific object.
Sources: space.com