Here's how Soviet engineers converted Yuri Gagarin's spacecraft into a spy satellite
The Soviet history is full of fascinating space endeavours and aircraft, and the Zenit Spy satellite is undoubtedly one of them. However, don't confuse it with a similarly named Zenit rocket, as it's essentially the Vostok spacecraft with cameras in place instead of the cosmonaut. And certainly don't confuse it with Zenit cameras, which were perhaps the most well-known of the three due to their simple yet bulletproof design.
Between the 1960s and 1990s, the satellite performed optical reconnaissance for the Soviet military, flying more than 650 times and inspiring some other science variants that flew for even longer. Apparently, all of these designs have the 2.3-meter spherical return capsule in common, a design chosen by Sergei Korolev to meet both Kruschev's demand for human space flight and and the military's desire for spy satellites. This video, produced by YouTuber Scott Manley, is packed with information and does a fantastic job of describing this intriguing instrument, as well as documenting the differences between Soviet and American design. If you're interested in learning more, check out the video attached above, and as usual, enjoy.