We choose to go to the moon in this decade” John F. Kennedy told Rice university students and the nation in 1962, “because that challenge is one that we are willing to accept … and one which we intend to win”. But first, they had to explore the moon. Landing on another celestial body was harder that just going into space: it was further, more difficult to get to, and less explored. NASA decided to map out and get some readings of the moon by a dual series of spacecraft, the Lunar Orbiter and the Lunar Lander.

On this day, May 4, the Lunar Orbiter 4, of at least five planned (a sixth was considered, but ultimately rejected), took off on the way to the moon. The Orbiter was intended to circle around the far side of the moon and store photographs.

The mission was partly a success. While the Orbiter did photograph all of the near side of the moon at levels much greater than what the best earth-based photography could do, problems with the satellite’s thermal door created issues with lens fogging and solar flare interference, causing mission control to change the satellite’s course to lay the ground for the Lunar Lander 5, instead of continuing its own scientific research.