On this day in 1967, NASA launched Lunar Orbiter 4 to continue a survey of the Moon (also conducted by three previous Lunar Orbiter missions) in preparation of the Apollo Moon missions. While NASA lost contact with the spacecraft on July 17th, the mission was a success. On October 6th, the spacecraft crashed onto the Moon’s surface. A total of five such missions were conducted, which mapped 99 percent of the Moon.
The rest is history with the successful Apollo missions, still the only program to land humans on the Moon. We shall see who follows in our footsteps, though we will be back on the Moon soon enough as part of the Artemis Program.
You can read more about the Lunar Orbiter missions at this NASA history link. The conclusion on the Lunar Orbiter missions states:
On September 2 Homer E. Newello Associate Administrator for Space Science and Applications, certified that the fifth mission was an unqualified success according to prelaunch objectives. Deputy Administrator Robert C. Seamans, Jr., concurred on September 6. Both NASA officials also assessed the whole program as successful; five missions had been flown out of five planned. Indeed the final Orbiter had capped an impressive effort by the Office of Space Science and Applications to bring man closer to stepping down upon the lunar soil and understanding where it was that he would be landing in the near future…
Five Orbiters had enabled the Manned Space Flight Network to train personnel in tracking and to check out equipment and computer programs for the manned lunar missions beginning with Apollo 8 in December 1968 and including Apollo 10 through 17, of which all but Apollo 10 and 13 landed on the Moon. (Apollo 10 tested the complete spacecraft in lunar orbit and Apollo 13 aborted its landing mission because an onboard oxygen tank exploded in cislunar space.) The Office of Manned Space Flight could not have obtained the needed tracking experience at a timely date if NASA had not flown the five Lunar Orbiter spacecraft.