The primary objectives of the Surveyor program, were to support the Apollo landings by: (1) developing and validating the technology for landing softly on the Moon; (2) providing data on the compatibility of the Apollo design with conditions encountered on the lunar surface; and (3) adding to the scientific knowledge of the Moon.
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.
“Dear friends, you who are close to me, and you whom I do not know, fellow Russians, and people of all countries and all continents: in a few minutes a powerful space vehicle will carry me into the distant realm of space. What can I tell you in these last minutes before the launch? My whole life appears to me as one beautiful moment. All that I previously lived through and did, was lived through and done for the sake of this moment.” Yuri Gagarin prior to launch of Vostok 1.
“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