As far as the intermission goes, this is not one of the most popular, but it is the one that gave us the first ever view of the lunar far side. I'm Amy Shire title and this week on Winter Space we're talking about the first time we ever saw the hidden face of the moon. The moon is tidally locked to the earth. It rotates around its axis in the time it takes to make one orbit around the earth, which means we always see the same side of the moon. The far side is always hidden, but once the space age began, the moon's mysteries or at least some of them were among the first to be solved. Both the Soviet Union and the United States started sending probes to the moon not long after getting their first satellites into orbit. Being so relatively close to home, it was a natural first target for early space missions. After launching history's first satellite out of the Earth's gravity in January of 1959, the Soviet Union launched Luna 3 on October 4 of that year. Two years to the day after launching Sputnik into orbit. Luna 3 was a small cylindrical spacecraft whose body was hermetically sealed and pressurized to 0.23 atmospheres to help keep its instruments working. Among those instruments was a dual lens camera fixed to the end of the spacecraft as well as an automatic film processing unit and a scanner both stored inside the spacecraft's body. Four days after launch, Luna 3 was 40,000 miles from the moon whose far side was facing the sun. When that reflected sunlight hit a photo cell on the spacecraft, it initiated the photography sequence. The first picture was taken 39,457 miles from the surface. The last image was taken 40 minutes later from the distance of 41,445 miles. In all, Luna 3 took 29 photographs that covered about 70% of the moon's far side. The exposed film was transferred into the processing unit inside the spacecraft where it was developed, fixed and dried. Then it was transferred into a scanner where a cathode ray tube projected a light on the image to project it onto a photoelectric multiplier that converted the light's intensity into an electric signal. That signal was then transmitted to Earth. 17 noisy but discernible pictures were transferred to the Earth before contact with the spacecraft was lost on October 22nd. And the picture isn't nearly as clear as later images taken by a Poe astronauts, but it was good enough to serve as the basis of the first tentative map of the moon's hidden face. Even if it's not a fantastic picture, there's something about seeing something like the far side of the moon for the first time that's pretty incredible. What do you guys think of Luna 3's images? Leave your questions, comments and any thoughts below. And for a more detailed look at Luna 3's mission, check out the latest article on vintage space over at Popular Science. You can grab me on Twitter as AST, Vintage Space, and for weekly Vintage Space video updates, don't forget to subscribe.