A short history of the Atlas Rocket

Background

Recently, the X-37B spaceplane lifted off from Cape Canaveral using a United Space Alliance Atlas V as a booster.  What is not commonly known by today’s space enthusiasts is that the current version of this booster can trace its origins back in 1957 when the first Atlas flew.

History

During the Cold War, the United States Air Force required a heavy lift ICBM.  Convair division of General Dynamics began the development of a liquid-fueled missile with a unique stage and a half design.  The skin of the vehicle was so thin it could not support the weight of the rocket. Convair engineers developed a “balloon” which was its fuel tank, always kept under pressure with either propellant or nitrogen gas to provide the needed rigidity.  At launch three engines would fire using RP-1 and LOX as fuel. Staging would have the two outboard engines jettisoned along with supporting structures, while the center sustainer engine, propellant tanks, and other structural elements remained connected through propellant depletion and engine shutdown.

Its life as an ICBM was relatively short. After entering service in 1959, the Atlas was replaced by the hypergolic fueled Titian and the solid-fueled Minuteman. Both newer missiles could launch much faster than the Atlas, which required over 30 minutes of preparation time.

New Life

While its use as an ICBM was history, the Atlas became a favorite of NASA and the Air Force as a multi-purpose launcher. NASA used the Atlas for four manned Mercury flights. Mated with an Agena upper stage the Atlas launched target vehicles for the Gemini docking missions. Mated with a Centaur the Atlas was used to launch Ranger moon exploratory and GPS satellite deployment missions.

In 2004 the last “classic” Atlas using the unique stage and a half design balloon was launched. Soon, a new variant would come into service, the Atlas III using a Russian Energomash RD-180 as a single engine first stage and a Centaur for the second, eliminating the one and a half stage operation.

Lockheed Martin, which gained the Atlas through acquisition, redesigned the launcher as part of the Evolved Expendable Launch Vehicle program. The newest version or Atlas V uses the RD-180 as the first stage core, with a Centaur upper stage configured with one or two Rocketdyne RL-10 engines. Up to five strap-on, solid rocket boosters can be added depending on the mission. In 2006 Lockheed Martin and Boeing space operations were merged to create the United Space Alliance which has been actively marketing the Atlas V as an alternative to the alliance’s other vehicles the Delta IV Heavy.

The Future

The U.S. Congress passed legislation in 2014 that would essentially phase out the Atlas V by prohibiting the use of the Russian built RD-180 engine. Sometime during 2021 a new common launch vehicle, the Vulcan would replace both the Atlas V and Delta IV Heavy. The engines for the Vulcan are under development through a partnership between ULA and Blue Origin Aerospace. The engine – BE4 will use LOX and methane finally replacing the Russian engine on U.S. launch vehicles. 

Summary

The history of the Atlas was common during the Cold War. Military ICBM’s were quickly repurposed and man rated to send early travelers into earth orbit.  Only the Saturn 1 and 5 were built especially for manned flight with no military application. Today all man rated boosters with the exception of the SpaceX Falcon 9 in use in the U.S., Russia and China are derived from military purposes.  The last flight of a vehicle with the Atlas name is expected to occur during 2020, closing out a history of over 300 launches from Cape Canaveral and about 285 from Vandenberg, all successful.