The first US intercontinental ballistic missile, Atlas was declared operational in 1959 and stood alert for nearly six years. On December 18, 1958, Project Score, an Atlas booster with a communications repeater satellite, was launched into Earth orbit. The satellite carried a Christmas message from President Dwight D. Eisenhower that was broadcast to Earth, which marked the first time a human voice had been heard from space. On May 20, 1960, an Atlas was launched from Cape Canaveral AFS, Fla., that carried a 1.5-ton payload 9,040 miles to the Indian Ocean, the greatest distance ever flown by a US ICBM. The missile found greater fame as an unmanned booster. However, on February 20, 1962, Marine Corps Lt. Col. John H. Glenn, Jr., made the first US orbital space mission when he was launched from Cape Canaveral on an Atlas booster and circled the Earth three times. The three later Mercury missions also used Atlas as a booster. Atlas was also used to launch the Ranger, Surveyor, and Mariner series of interplanetary probes. The stainless-steel structure on the booster was so thin that the tanks had to be pressurized with helium at all times to support the weight of its own skin.

Contractors:	Astronautics Division of General Dynamics (Convair)
Locations Built:	San Diego, Calif.
Number Built: (USAF)	Unconfirmed (126 operational missiles at peak deployment)
First Launch:	June 11, 1957
First Flight Model:	XSM-65A
First Flight Location:	Cape Canaveral AFS, Fla
Models/Variants:	M-65A, B, C, D (later redesignated CGM-16A, B, C, D). CGM-16E. HGM-16F
Powerplant:	One Rocketdyne LR89-NA-3 liquid fuel sustainer engine of 57,000 lb thrust, two Rocketdyne LR105 liquid fuel booster engines of 150,000 lb thrust each, and two Rocketdyne LR101 liquid fuel vernier engines of 1,000 lb thrust each
Diameter:	10 ft 0 in.
Height:	82 ft 5 in.
Weight:	260,000 lb.
Armament:	One Mk. 4 reentry vehicle with a W-38 nuclear warhead with a yield of three to four megatons
Cost:	$1.7 million
Max. Speed:	More than 16,000 mph
Range:	More than 6,800 mi.
Ceiling:	640 mi.