The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the Convair Division of General Dynamics.

"[7][8][9] The communications payload was placed into low Earth orbit on Atlas serial number 10B without an upper stage.

Atlas saw the beginnings of its "workhorse" status during the Mercury-Atlas missions, which resulted in Lt. Col. John H. Glenn Jr. becoming the first American to orbit the Earth in 1962.

Beginning in 1960, the Agena upper stage, powered by hypergolic propellant, was used extensively on Atlas launch vehicles.

[12] NASA used them in the Ranger program to obtain the first close-up images of the surface of the Moon and for Mariner 2, the first spacecraft to fly by another planet.

The Atlas' engines were upgraded and the structure reinforced for the large upper stage, along with elongated propellant tanks.

[19] The Atlas V, currently in service, was developed by Lockheed Martin as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program.

In 2006, operation was transferred to United Launch Alliance (ULA), a joint venture between Lockheed Martin and Boeing.

Lockheed Martin continued to market the Atlas V to commercial customers until September 2021, when it announced that the rocket will be retired after fulfilling the remaining 29 launch contracts.

The rigid fuselage is heavier, but easier to handle and transport, eliminating the need for constant internal pressure.

[24] In September 2014, ULA announced that it had entered into a partnership with Blue Origin to develop the BE-4 LOX/methane engine to replace the RD-180 on the new Vulcan rocket.

In December 2014, legislation to prevent the award of further military launch contracts to vehicles that use Russian-made engines was approved by the US Congress.

The Atlas V Heavy was a ULA concept proposal that would have used three Common Core Booster (CCB) stages strapped together to provide the capability necessary to lift a 55,000-pound (25 t) payload to low Earth orbit.

[citation needed] A 2006 report, prepared by RAND Corporation for the Office of the Secretary of Defense, stated that Lockheed Martin had decided not to develop an Atlas V heavy-lift vehicle (HLV).

"[27][needs update] The lifting capability of the Atlas V HLV was to be roughly equivalent to the Delta IV Heavy.

[28] After December 2006, with the merger of Boeing and Lockheed-Martin space operations into United Launch Alliance, the Atlas V program gained access to the tooling and processes for 18 ft (5.4 m) diameter stages used on Delta IV.

[29] The Atlas PH2 HLV concept vehicle would have notionally been able to launch a payload mass of approximately 150,000 pounds (70 t) into an orbit of 28.5 degree inclination.