Atlas is a family of US missiles and space

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...

s that originated with the

SM-65 Atlas The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dy ...

. The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the

Convair Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, i ...

Division of General Dynamics. Atlas was a

liquid propellant rocket A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid propellants. Liquids are desirable because they have a reasonably high density and high specific impulse (''I''sp). This allows the volume of the propellant ta ...

burning

RP-1 RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is s ...

fuel with

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an app ...

in three engines configured in an unusual "stage-and-a-half" or "parallel staging" design: two outboard booster engines were jettisoned along with supporting structures during ascent, while the center sustainer engine, propellant tanks and other structural elements remained connected through propellant depletion and engine shutdown. The Atlas name was originally proposed by

Karel Bossart Karel Jan Bossart (February 9, 1904 – August 3, 1975) was an innovative rocket designer and creator of the Atlas ICBM. His achievements rank alongside those of Wernher von Braun and Sergei Korolev. But as most of his work was for the United ...

and his design team working at

on project MX-1593. Using the name of a mighty titan from Greek mythology reflected the missile's place as the biggest and most powerful at the time. It also reflected the parent company of Convair, the

Atlas Corporation The Atlas Corporation is an American investment firm that was formed in 1928. Atlas invested in and managed a number of major US companies during the 20th century and has a number of investments in natural resources. History Atlas corporation wa ...

. The missiles saw only brief ICBM service, and the last squadron was taken off operational alert in 1965. However, from 1962 to 1963 Atlas boosters launched the first four US astronauts to

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

the Earth (in contrast to the preceding two Redstone suborbital launches). The

Atlas-Agena The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was launched 109 times between 1960 and 1978. It was used to launch the first five Mariner uncrew ...

and

Atlas-Centaur The Atlas-Centaur was a United States expendable launch vehicle derived from the SM-65 Atlas D missile. Launches were conducted from Launch Complex 36 at the Cape Canaveral Air Force Station (CCAFS) in Florida. Early development Convair, ...

satellite launch vehicles were also derived directly from the original Atlas. The Atlas-Centaur was evolved into the

Atlas II Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first stage tanks, higher-performing engine ...

, various models of which were launched 63 times between 1991 and 2004. There were only six launches of the succeeding Atlas III, all between 2000 and 2005. The

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

is still in service, with launches planned into the 2020s. More than 300 Atlas launches have been conducted from

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

in Florida and 285 from

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from ...

in California.

Launch vehicles based on original Atlas ICBM

The Atlas was used as an expendable launch system, with both the Agena and Centaur upper stages, for the

Mariner A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship. The profession of the ...

space probes used to explore Mercury,

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

, and

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

(1962–1973); and to launch ten of the

Mercury program Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...

missions (1962–1963).

SM-65 Atlas missile

SM-65A Atlas missile, 1958 The first successful test launch of an SM-65 Atlas missile was on 17 December 1957. Approximately 350 Atlas missiles were built. The Atlas boosters would collapse under their own weight if not kept pressurized with nitrogen gas in the tanks when devoid of propellants. The Atlas booster was unusual in its use of "balloon" tanks. 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. In order to save weight they were not painted and needed a specially designed oil to prevent rust. This was the original use of

WD-40 WD-40 is an American brand and the trademark of a penetrating oil manufactured by the WD-40 Company based in San Diego, California. The formula for WD-40 was invented for the Rocket Chemical Company as early as 1953 before it evolved into ...

water displacement oil. The SM-65 Atlas was used as a first stage for satellite launch vehicles for half a century. Many were eventually converted to orbital launch vehicles after they were removed from service as missiles. Missiles converted into

Atlas E/F The Atlas E/F (or SB-1A) was an American expendable launch system and sounding rocket built using parts of decommissioned SM-65 Atlas missiles. It was a member of the Atlas family of rockets. The first stage was built using parts taken from d ...

"space boosters" were used to launch the early "Block I"

GPS satellites GPS satellite blocks are the various production generations of the Global Positioning System (GPS) used for satellite navigation. The first satellite in the system, Navstar 1, was launched on 22 February 1978. The GPS satellite constellatio ...

SM-65B Atlas SCORE launch

Early Atlas rockets were also built specifically for non-military uses. On 18 December 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 A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth ...

, and the first test of any satellite for direct practical applications." The communications payload was placed into

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

on Atlas serial number 10B without an upper stage. Atlas 10B/SCORE, at was the heaviest artificial object then in orbit, the first voice relay satellite, and the first human-made object in space easily visible to the naked eye due to the large, mirror-polished stainless steel tank. This was the first flight in what would be a long career for the Atlas as a satellite launcher.

Atlas-D based launchers

Atlas D missile-derived SLV-3s were used for

al launches with the

RM-81 Agena The RM-81 Agena was an American rocket upper stage and satellite bus which was developed by Lockheed Corporation initially for the canceled WS-117L reconnaissance satellite program. Following the split-up of WS-117L into SAMOS and Corona for imag ...

and Centaur upper stages. The modified

Atlas LV-3B The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a human-rated expendable launch system used as part of the United States Project Mercury to send astronauts into low Earth orbit. Manufactured by Convair, it w ...

was used for the orbital element of

Project Mercury Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...

, launching four crewed

Mercury spacecraft Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...

into

. Atlas D launches were conducted from Cape Canaveral Air Force Station, at Launch Complexes 11, 12, 13 and 14, and

Vandenberg AFB Launch Complex 576 Launch Complex 576 is a group of rocket launch pads at Vandenberg Space Force Base. The pads were used from 1959 until 1971 to launch SM-65 Atlas missiles. The site was also known as Complex ABRES. Pads in Area 576 include 576A-1, 576A-2 and 5 ...

. Two suborbital

stage and a half A single-stage-to-orbit (SSTO) vehicle reaches orbit from the surface of a body using only propellants and fluids and without expending tanks, engines, or other major hardware. The term usually, but not exclusively, refers to reusable vehicles ...

vehicles were used during

Project FIRE A project is any undertaking, carried out individually or collaboratively and possibly involving research or design, that is carefully planned to achieve a particular goal. An alternative view sees a project managerialism, managerially as a se ...

as sounding rockets. By 1979, Atlas space launcher variants had been whittled down to just the Atlas-Centaur and some refurbished ICBMs. The launch rate of Atlases decreased in the 1980s due to the advent of the

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...

, but Atlas launches continued until 2004, when the last "classic" Atlas with balloon tanks and the jettisonable booster section launched a comsat for the Air Force.

Mercury program

Mercury-Atlas 9 at Launch Complex 14 Atlas boosters were also used for the last four crewed

missions, the first United States crewed 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 crewed Mercury orbital missions from 1962 to 1963. Atlas saw the beginnings of its "workhorse" status during the

Mercury-Atlas Mercury-Atlas was a subprogram of Project Mercury that included most of the flights and tests using the Atlas LV-3B The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a human-rated expendable launch system u ...

missions, which resulted in Lt. Col. John H. Glenn Jr. becoming the first American to orbit the Earth in 1962 (Major Yuri A. Gagarin, a Soviet cosmonaut, was the first human in orbit in 1961.) Atlas was also used throughout the mid-1960s to launch the Agena Target Vehicles used during the Gemini program.

Atlas-Agena

Atlas-Agena Beginning in 1960, the Agena

upper stage A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is ...

, powered by hypergolic propellant, was used extensively on Atlas launch vehicles. The

United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

NRO NRO may stand for: * National Reconciliation Ordinance, a Pakistani law * National Reconnaissance Office, maintains United States reconnaissance * National Repertory Orchestra, in Colorado * ''National Review Online'', web version of the magazine ...

and

CIA The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian foreign intelligence service of the federal government of the United States, officially tasked with gathering, processing, ...

used them to launch

SIGINT Signals intelligence (SIGINT) is intelligence-gathering by interception of '' signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ...

satellites. NASA used them in the

Ranger program The Ranger program was a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surf ...

to obtain the first close-up images of the surface of the Moon and for

Mariner 2 Mariner 2 (Mariner-Venus 1962), an American space probe to Venus, was the first robotic space probe to conduct a successful planetary encounter. The first successful spacecraft in the NASA Mariner program, it was a simplified version of the B ...

, the first spacecraft to fly by another planet. Each of the Agena target vehicles used for the later

space rendezvous A space rendezvous () is a set of orbital maneuvers during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance (e.g. within visual contact). Rendezvous requires a precise ...

practice missions of

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Norther ...

was launched on an Atlas rocket.

Atlas-Centaur

Atlas-Centaur The Atlas-Centaur was an expendable launch system derived from the

SM-65D Atlas The SM-65D Atlas, or Atlas D, was the first operational version of the U.S. Atlas missile. Atlas D was first used as an intercontinental ballistic missile (ICBM) to deliver a nuclear weapon payload on a suborbital trajectory. It was later deve ...

missile. Launches were conducted from two pads of the

Launch Complex 36 Launch Complex 36 (LC-36)—formerly known as Space Launch Complex 36 (SLC-36) from 1997 to 2010—is a launch complex at Cape Canaveral Space Force Station in Brevard County, Florida. It was used for Atlas launches by NASA and the U.S. Air Force ...

at Cape Canaveral Air Force Station, Florida. The Atlas' engines were upgraded and the structure reinforced for the large upper stage, along with elongated propellant tanks. The first launch attempt of an Atlas-Centaur in May 1962 failed, the rocket exploding after take-off. Footage of this was shown in the penultimate shot of the 1983 art film ''Koyaanisqatsi'', directed by Godfrey Reggio. Beginning in 1963, the liquid hydrogen-fueled Centaur upper stage was also used on dozens of Atlas launches. NASA launched the Surveyor program lunar lander spacecraft and most of the Mars-bound Mariner program spacecraft with Atlas-Centaur launch vehicles.

Atlas E/F

Following retirement as an ICBM, the Atlas-E, along with the SM-65F Atlas, Atlas-F, was refurbished for

al launches. The last Atlas E/F spacecraft launch was conducted on 24 March 1995, using a rocket which had originally been built as an Atlas-E. The last Atlas E/F launch to use a rocket which had originally been built as an Atlas-F was conducted on 23 June 1981. Atlas E/F was used to launch the Block I series of GPS satellites from 1978 to 1985. The last refurbished Atlas-F vehicle was launched from Vandenberg AFB in 1995 carrying a satellite for the Defense Meteorological Satellite Program.

Tabulated

RD-180 era

Atlas III

The first stage of the Atlas III discontinued the use of three engines and 1.5 staging in favor of a single Russian-built Energomash RD-180 engine, while retaining the stage's balloon tank construction. The Atlas III continued to use the Centaur upper stage, available with single or dual RL10 engines.

Atlas V

The Atlas V, currently in service, was developed by Lockheed Martin as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program. The first was launched on August 21, 2002. 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. Atlas V is built in Decatur, Alabama, and maintains two launch sites: Cape Canaveral Air Force Station Space Launch Complex 41, Space Launch Complex 41 at

and Vandenberg AFB Space Launch Complex 3, Space Launch Complex 3-E at

. The Atlas V's first stage is called the Common Core Booster (CCB), which continues to use the Energomash RD-180 introduced in the Atlas III, but employs a rigid framework instead of balloon tanks. The rigid fuselage is heavier, but easier to handle and transport, eliminating the need for constant internal pressure. Up to five Aerojet Rocketdyne strap-on solid rocket boosters can be used to augment first stage thrust. The upper stage remains the Centaur, powered by a single or dual Aerojet Rocketdyne RL10 engines.

RD-180 phaseout

In 2014, US Congress passed legislation restricting the purchase and use of the Russia, Russian-supplied RD-180 engine used on the first stage booster of the Atlas V. Formal study contracts were issued in June 2014 to a number of US rocket engine suppliers. In September 2014, ULA announced that it had entered into a partnership with Blue Origin to develop the BE-4 LOX/Liquid methane, methane engine to replace the RD-180 on the new Vulcan (rocket), Vulcan rocket. The engine has been in development for 8 years by Blue Origin, and ULA expects the new stage and engine to start flying no earlier than 2022. In December 2014, legislation to prevent the award of further military launch contracts to vehicles that use Russian-made engines was approved by the United States Congress, US Congress. The bill allows ULA to continue to use the 29 RD-180 engines already on order at the time. In September 2021, ULA announced that Atlas V will be retired after they fulfill their remaining launch contracts, and that all remaining RD-180s for the remaining rockets have been delivered.

Formerly-proposed launch vehicles

Prior to the April 2015 announcement of the Vulcan launch vehicle, during the first decade since ULA was formed from Lockheed Martin and Boeing, there were a number of proposals and concept studies of future launch vehicles. None were subsequently funded for full-up development. Two of those concepts were the ''Atlas V Heavy'' and the ''Atlas Phase 2''.

Atlas V Heavy

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 25 tonne payload to

. ULA stated that approximately 95% of the hardware required for the Atlas HLV had already been flown on the Atlas V single-core vehicles. 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). The report recommended for the Air Force and the National Reconnaissance Office to "determine the necessity of an EELV heavy-lift variant, including development of an Atlas V Heavy", and to "resolve the RD-180 issue, including coproduction, stockpiling, stockpile, or U.S. development of an RD-180 replacement." The lifting capability of the Atlas V HLV was to be roughly equivalent to the Delta IV Heavy. The latter utilizes RS-68 engines developed and produced domestically by Pratt & Whitney Rocketdyne.Atlas V EELV – Lockheed-Martin Retrieved on 2008-02-08
Globalsecurity.org. Retrieved on 2011-11-19.

Atlas V Phase 2

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 5.4 m diameter stages used on Delta IV. A 5.4 m diameter stage could have conceivably accepted dual RD-180 engines. The resulting conceptual heavy-lift vehicle was called ''"Atlas Phase 2"'' or "PH2" in the 2009 Review of United States Human Space Flight Plans Committee, Augustine Report. An Atlas V PH2-Heavy (three 5 m stages in parallel; six RD-180s) along with Shuttle-Derived Launch Vehicle, Shuttle-derived, Ares V and Ares V Lite, were considered as a possible heavy lifter concept for use in future space missions in the Augustine Report. The Atlas PH2 HLV concept vehicle would have notionally been able to launch a payload mass of approximately 70 metric tons into an orbit of 28.5 degree-Orbital inclination#Natural and artificial satellites, inclination. The concept did not proceed onto full development, and was never built.

References

External links

Atlas at Encyclopedia Astronautica
{{DEFAULTSORT:Atlas (Rocket Family) Atlas (rocket family), 1957 in spaceflight 1961 in spaceflight 1962 in spaceflight United Launch Alliance space launch vehicles NASA space launch vehicles Rocket families