Lunar Probe Able 1
The first attempt by America to send a probe to the Moon, Able 1 ended in failure. After just 77 seconds when Able 1 was 12 miles high the lower stage of the rocket exploded destroying the probe. It would not be until Ranger 7 in 1964 that the Americans successfully launched a Moon mission.
In those days the Americans were well behind the Russian who had already sent probes to the Moon by 1959.
All these early missions were unmanned.