1960-05-20 USA Atlas-D Launch

LC-12's first launch was Atlas 10A on January 10, 1958. During the second half of the year, a larger umbilical service tower was built in preparation for the C series Atlas tests, flown from December 1958 to August 1959. On September 24, 1959, the first Atlas-Able, 9C, exploded during a static firing test at LC-12, after a turbopump on one of the engines failed to trigger a complete engine shutdown. The damaged turbopump continued to allow oxidizer to flow, feeding the fire beneath the vehicle. About a minute later the rocket suffered a structural failure, collapsed and exploded. The entire service tower and both umbilical towers were knocked over and the concrete launch stand caved in. Because damage to LC-12 was so extensive, it did not host another launch until Missile 56D in May 20, 1960. The large service tower was not rebuilt following the explosion of Atlas 9C. It then hosted more ICBM tests along with the second and third Atlas Able probes.

Successful launch of Atlas D Missile 56D on May 20, 1960 from Launch Complex 12 (LC-12) at Cape Canaveral.

In 1961, LC-12 was converted to support the Atlas-Agena rocket. The first Atlas-Agena launch from LC-12 was in August 1961. On April 23, 1962, Atlas-Agena B 133D launched Ranger 4, the first American spacecraft to reach the surface of the Moon, when it made a hard landing at an impact speed of 9,617 kilometres per hour (5,976 mph).

(Reference from Cape Canaveral Launch Complex 12)