On this day in 1962, the United States launched the Ranger 4 lunar probe from Cape Canaveral. Its mission was to photograph the lunar surface, place scientific equipment on the Moon, and perform other tests before crashing into the surface of the Moon. A computer glitch caused the probe to crash on the far side of the Moon before it could send back any useful data. Nonetheless, it was the first US spacecraft to reach another moon or planet (the Soviets had reached the Moon in 1959) as well as the first spacecraft to reach the far side of the Moon.
NASA launched a total of nine probes to the Moon under the Ranger program, with the last missions – Rangers 7,8, and 9 – being successful. Rangers 1 and 2 never left Earth orbit, while Rangers 3 and 5 missed the moon altogether. As noted above, Ranger 4 made it to the Moon, but not where is was supposed to land. And Ranger 6 made it to the Moon, but experienced a camera failure.
The Ranger missions set the stage for the later Apollo missions, which allowed the US to put the first man on the Moon.
Note: This NASA paper, Lunar Impact: A History of Project Ranger, provides greater detail on the earlier missions.
Our Awesome Universe 