A total of five Lunar Orbiter missions were launched by the US in 1966 through 1967. The purpose of the lunar orbiter series was to photograph the moon’s surface for selection and verification of safe landing sites for the Surveyor and Apollo missions.
After 1957, the Soviets became accustomed to achieving “world firsts” in space accomplishments. Nevertheless, 10 years later they were not confident that they could pull off the world’s first fully automatic rendezvous and docking of two un-piloted Soyuz spacecraft. At the time the chance for success was estimated at only 50/50.
“It seemed that the nearby and mysterious planet was resorting to tricks to hide the secrets kept beneath its cover of clouds. As the probe drew nearer, Venus’ gravitational field increased its speed. The Doppler effect altered the wavelength of the signals received on Earth. The radio operators needed to be particularly vigilant so that the information sent from the station consistently landed in the narrow “throat” of the ground-based receivers.” Boris Chertok
“It’s a terrible scene. Komarov burned up. All the instruments burned. We must quickly find out what prevented the main parachute from unlatching.” Chief Designer Mishin after he arrived at the Soyuz 1 crash site.