"This first launch failure, though disappointing, also contained a silver lining. As the missile was tumbling out of control, the Atlas' frame and thin skin remained intact, even though subjected to several seconds of very high aerodynamic stress (or structural “loads”) far in excess of its design limitations. This validated its structural integrity and ended the controversy over its unconventional design. In all, a total of eight Atlas Series A missiles were launched from June 1957 though June 1958.
"Subsequent test versions (the “B” and “C” models) were launched in 1958 and 1959, and the Atlas D, the U.S.' first ICBM, became a functional weapon system in January 1959 when the first Atlas ICBM squadron at Vandenberg Air Force Base, California was activated, even before the first successful launch of the Atlas D. The Air Force formally accepted the Atlas on September 1, 1959, and the missile was declared "operational" about a week later when an Atlas D ICBM was successfully launched from Vandenberg.
"During the same timeframe, the Atlas missile was also proving its worth as a space launch vehicle. Project Score-an Atlas B missile that launched itself into low-Earth-orbit on December 18, 1958-carried an instrumentation package developed by the U.S. Army Signal Corps that became the world's first communications satellite by broadcasting a recorded Christmas message from President Eisenhower back to Earth.
"Atlas model D, E, and F ICBMs, outfitted with nuclear warheads, were deployed at Air Force bases throughout the United States, stored vertically in underground silos and raised by elevators to an above-ground position for launch. In addition to the original squadron at Vandenberg AFB, Atlas ICBMs were deployed at eight locations in central and western United States and at Plattsburg AFB, New York. (Plattsburg AFB still is the only ICBM installation ever located east of the Mississippi River).
Atlas ICBMs remained on strategic alert from 1959 until 1966, when more capable solid-fuelled Minuteman ICBMs replaced the last Atlas missiles. A number of these decommissioned Atlas ICBMs were refurbished for use by the Air Force and the National Aeronautics and Space Administration (NASA) as satellite launch vehicles; the last refurbished Atlas was launched from Vandenberg AFB with a military meteorology satellite in 1995.
"NASA ordered a number of “man-rated” (modified with safety features to carry humans) Atlas D models-designated as the Atlas LV-3B-for the orbital flights of its first human spaceflight program, Project Mercury. Astronaut John H. Glenn, Jr. became the first American to orbit the Earth in his Friendship 7 Mercury capsule launched atop an Atlas LV-3B on February 20, 1962, followed by astronauts Carpenter, Schirra and Cooper in 1962 and 1963."