Atlas (rocket family)

Atlas is a family of United States space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics, to be used as an intercontinental ballistic missile (ICBM). It was a liquid-fuel rocket burning liquid oxygen and RP-1 in three engines configured in an unusual “stage-and-a-half” or “Parallel Staging” design: its two outboard booster engines were jettisoned during ascent, while its center sustainer engine, fuel tanks and other structural elements were retained into orbit.

The missiles saw only brief ICBM service, and the last squadron was taken off operational alert in 1965. From 1962 to 1963, Atlas boosters launched the first four American astronauts to orbit the Earth. Various Atlas II models were launched 63 times between 1991 and 2004. There were only six launches of the Atlas III, all between 2000 and 2005. The Atlas V is still in service, with launches planned until 2020.

More than 300 Atlas launches have been conducted from Cape Canaveral Air Force Station in Florida and 285 from Vandenberg Air Force Base in California.

Early Atlas rockets were also built specifically for non-military uses. On December 18, 1958, an Atlas was used to launch the Signal Communication by Orbiting Relay Equipment (SCORE) satellite, which was, “The first prototype of a communications satellite, and the first test of any satellite for direct practical applications.” The satellite broadcast President Eisenhower’s pre-recorded Christmas message around the world.

The Atlas boosters would collapse under their own weight if not kept pressurized with nitrogen gas in the tank, even when not fueled. The Atlas booster was unusual in its use of balloon tanks for holding its fuel. The rockets were made from very thin stainless steel that offered minimal or no rigid support. It was pressure in the tanks that gave the rigidity required for space flight.

Atlas boosters were also used for the last four manned Project Mercury missions, the first United States manned space program. On February 20, 1962 it launched Friendship 7, which made three earth orbits carrying John Glenn, the first United States astronaut to orbit the Earth. Identical Atlas boosters successfully launched three more manned Mercury orbital missions from 1962 to 1963.

Image credit: San Diego Air & Space Museum