| Atlas family | |
|---|---|
 Atlas II, III and V comparison | |
| General information | |
| Type | Expendable launch system with various applications |
| Manufacturer | Convair General Dynamics Lockheed Martin United Launch Alliance |
| Status | Atlas V (current) |
| Primary users | United States Air Force |
| History | |
| Manufactured | 1957–2010s (decade) |
| Introduction date | 1957 |
| First flight | December 17, 1957; 67 years ago (1957-12-17)[1] |
| Variants | SM-65 Atlas SM-65D Atlas Atlas LV-3C Atlas IIIA Atlas V |
Atlas is a family of US missiles and spacelaunch vehicles that originated with theSM-65 Atlas. The Atlasintercontinental ballistic missile (ICBM) program was initiated in the late 1950s under theConvair Division ofGeneral Dynamics.[2] Atlas was aliquid propellant rocket burningRP-1 kerosene fuel withliquid oxygen 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 byKarel Bossart and his design team working atConvair on project MX-1593. Using the name of amighty 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, theAtlas Corporation.[3]
The missiles saw only brief ICBM service, and the last squadron was taken off operational alert in 1965. However, from 1962 to 1963Atlas boosters launched the first four USastronauts toorbit the Earth (in contrast to the preceding twoRedstonesuborbital launches). TheAtlas-Agena andAtlas-Centaur satellite launch vehicles were also derived directly from the original Atlas. The Atlas-Centaur was evolved into theAtlas II, various models of which were launched 63 times between 1991 and 2004. There were only six launches of the succeedingAtlas III, all between 2000 and 2005. TheAtlas V is still in service, with launches planned into the mid-2020s.
More than 300 Atlas launches have been conducted fromCape Canaveral Space Force Station in Florida and 285 fromVandenberg Space Force Base in California.
The Atlas was used as anexpendable launch system, with both the Agena and Centaur upper stages, for theMariner space probes used to exploreMercury,Venus, andMars (1962–1973); and to launch ten of theMercury program missions (1962–1963).[citation needed]
The first successful test launch of an SM-65 Atlas missile was on 17 December 1957.[1] Approximately 350 Atlas missiles were built.[4]
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 ofWD-40 water displacement oil.[5]
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 intoAtlas E/F "space boosters" were used to launch the early "Block I"GPS satellites.[6]
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 acommunications satellite, and the first test of any satellite for direct practical applications."[7][8][9] The communications payload was placed intolow Earth orbit on Atlas serial number 10B without an upper stage. Atlas 10B/SCORE, at 8,750 lb (3,970 kg) 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 missile-derived SLV-3s were used fororbital launches with theRM-81 Agena andCentaur upper stages. The modifiedAtlas LV-3B was used for the orbital element ofProject Mercury, launching fourcrewedMercury spacecraft intolow Earth orbit.[10] Atlas D launches were conducted from Cape Canaveral Air Force Station, at Launch Complexes 11, 12, 13 and 14, andVandenberg AFB Launch Complex 576.[citation needed]
Twosuborbitalstage and a half vehicles were used duringProject FIRE assounding rockets.[10]
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 theSpace Shuttle, but Atlas launches continued until 2004, when the last "classic" Atlas withballoon tanks and the jettisonable booster section launched a comsat for the Air Force.[11]
Atlas boosters were also used for the last four crewedProject Mercury missions, the first United States crewed space program. On February 20, 1962, it launchedFriendship 7, which made three Earth orbits carryingJohn Glenn, the first United Statesastronaut 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 theMercury-Atlas missions, which resulted in Lt. Col.John H. Glenn Jr. becoming the first American to orbit the Earth in 1962. Atlas was also used throughout the mid-1960s to launch theAgena Target Vehicles used during theGemini program.
Beginning in 1960, theAgenaupper stage, powered byhypergolic propellant, was used extensively on Atlas launch vehicles. TheUnited States Air Force,NRO andCIA used them to launchSIGINT satellites.[12] NASA used them in theRanger program to obtain the first close-up images of the surface of the Moon and forMariner 2, the first spacecraft to fly by another planet. Each of theAgena target vehicles used for the laterspace rendezvous practice missions ofGemini was launched on an Atlas rocket.
The Atlas-Centaur was anexpendable launch system derived from theSM-65D Atlas missile.[citation needed] Launches were conducted from two pads of theLaunch Complex 36 atCape 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 1982 art filmKoyaanisqatsi, directed byGodfrey Reggio.
Beginning in 1963, theliquid hydrogen-fueledCentaur upper stage was also used on dozens of Atlas launches.NASA launched theSurveyor program lunar lander spacecraft and most of the Mars-boundMariner program spacecraft with Atlas-Centaur launch vehicles.
Following retirement as an ICBM, the Atlas-E, along with theAtlas-F, were refurbished fororbital launches.[10]
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.[13]
Atlas E/F was used to launch the Block I series ofGPS 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.[14]
| Model name | First launch | Last launch | Total launches | Successes | ICBM base | Upper stage | Notable payloads | Remarks |
|---|---|---|---|---|---|---|---|---|
| Atlas-Vega[15] | - | - | 0 | 0 | Atlas E | storable propellant stage | none | Development was essentially identical to Atlas-Agena, and cancelled accordingly in 1959 |
| Atlas-Able | 1959 | 1960 | 3 | 0 | Atlas-D/Able(Delta-A)[16] | Altair | Pioneer P-3,Pioneer P-30,Pioneer P-31 |  |
| Atlas LV-3A | 1960 | 1968 | 49 | 38 | Atlas D | Agena | Mariner 2,Ranger program,Missile Defense Alarm System |  |
| Atlas LV-3B | 1959 | 1963 | 9 | 9 | Atlas D | none | Friendship 7,Aurora 7,Sigma 7,Faith 7 |  |
| Atlas SLV-3 | 1964 | 1968 | 51 | 46 | Atlas D | Agena | Corona,KH-7 Gambit | same as LV-3A except reliability improvements |
| Atlas SLV-3A | 1969 | 1978 | 10 | 9 | Atlas D | Agena | Canyon | same as SLV-3 except stretched 9.7 ft (2.97 m) |
| Atlas SLV-3B[17] | 1966 | 1966 | 1 | 1 | Atlas D | Agena D | Orbiting Astronomical Observatory 1 | |
| Atlas LV-3C | 1963 | 1967 | 11 | 8 | Atlas D | Centaur C | Surveyor 1 |  |
| Atlas SLV-3C | 1967 | 1972 | 17 | 14 | Atlas D | Centaur D | ? | Same as LV-3C stretched 4.3 ft (1.3 m) |
| Atlas SLV-3D | 1973 | 1983 | 32 | 29 | Atlas D | Centaur D1A | Mariner 10 |  |
| Atlas G | 1984 | 1987 | 6 | 4 | Atlas G | Centaur D1A | ? |  |
| Atlas I | 1990 | 1997 | 11 | 8 | Atlas G derived | Centaur D1A derived | CRRES[18] |  |
| Atlas II | 1991 | 1998 | 10 | 10 | Atlas G derived | Centaur D1A derived | Eutelsat |  |
| Atlas IIA | 1992 | 2002 | 23 | 23 | Atlas G derived | Centaur D1A derived | - | Same as Atlas II except Centaur RL10 engines uprated to 20,000 lbf (88 kN) of thrust and 6.5-second Isp increase from extendible RL10 nozzles |
| Atlas IIAS | 1993 | 2004 | 30 | 30 | Atlas G derived[citation needed] | Centaur D1A derived | - | Same as Atlas IIA except four Castor IVA strap-on boosters added |
| Atlas D-OV1 | 1965 | 1967 | 7 | 6 | Atlas D | none | OV (Orbiting Vehicle) flights |  |
| Atlas E | 1980 | 1995 | 23 | 21 | Atlas E | none |  | |
| Atlas F | 1968 | 1981 | 23 | 22 | Atlas F | none | ? | ICBM refurbished for orbital launch |
| Atlas H | 1983 | 1987 | 5 | 5 | Modified Atlas G | Centaur stage removed | NOSS satellites |  |
The first stage of theAtlas III discontinued the use of three engines and 1.5 staging in favor of a single Russian-builtEnergomashRD-180 engine, while retaining the stage'sballoon tank construction. The Atlas III continued to use the Centaur upper stage, available with single or dualRL10 engines.[19]
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The Atlas V, currently in service, was developed byLockheed Martin as part of the US Air ForceEvolved Expendable Launch Vehicle (EELV) program. The first was launched on August 21, 2002. In 2006, operation was transferred toUnited Launch Alliance (ULA), a joint venture between Lockheed Martin andBoeing. 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.[20][21] Atlas V is built inDecatur, Alabama, and maintains two launch sites:Space Launch Complex 41 atCape Canaveral Space Force Station andSpace Launch Complex 3-E atVandenberg Space Force Base.
The Atlas V's first stage is called theCommon Core Booster (CCB), which continues to use the EnergomashRD-180 introduced in the Atlas III, but employs a rigid framework instead ofballoon tanks. The rigid fuselage is heavier, but easier to handle and transport, eliminating the need for constant internal pressure. Up to fiveAerojet Rocketdyne strap-onsolid rocket boosters can be used to augment first stage thrust. The upper stage remains theCentaur, powered by a single or dual Aerojet RocketdyneRL10 engines.[22]
| Model name | First launch | Last launch | Total launches | Successes | 1st-stage engines | Upper-stage engines | Notable payloads | Remarks |
|---|---|---|---|---|---|---|---|---|
| Atlas IIIA | 2000 | 2004 | 2 | 2 | 1xRD-180 | 1xRL10A | Eutelsat W4 |  |
| Atlas IIIB | 2002 | 2005 | 4 | 4 | 1xRD-180 | 1xRL10A | Same as Atlas IIIA, except for Centaur stretched 1.7 m and an optional dual engine Centaur. | |
| Atlas V 400 | 2002 | 2022 | 59 | 58 | 1xRD-180 | 1xRL10A | Lunar Reconnaissance Orbiter,LCROSS,Mars Reconnaissance Orbiter | |
| Atlas V 500 | 2003 | - | 18 | 18 | 1xRD-180 | 1xRL10A | New Horizons,X-37B,Mars Science Laboratory |  |
| Atlas V N22 | 2019 | - | 3 | 3 | 1xRD-180 | 2xRL10A | StarlinerBoeing OFT | .jpg) |
In 2014,US Congress passed legislation restricting the purchase and use of theRussian-suppliedRD-180 engine used on the first stage booster of the Atlas V.[23] Formal study contracts were issued in June 2014 to a number of US rocket engine suppliers.[24]
In September 2014, ULA announced that it had entered into a partnership withBlue Origin to develop theBE-4LOX/methane engine to replace the RD-180 on the newVulcan rocket. The new stage and engine first flew in 2024.
In December 2014, legislation to prevent the award of further military launch contracts to vehicles that use Russian-made engines was approved by theUS Congress. The bill allows ULA to continue to use the 29 RD-180 engines already on order at the time.[25] 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.[21]
Prior to the April 2015 announcement of theVulcan 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 theAtlas V Heavy and theAtlas Phase 2.
TheAtlas V Heavy was a ULA concept proposal that would have used threeCommon Core Booster (CCB) stages strapped together to provide the capability necessary to lift a 55,000-pound (25 t) payload tolow Earth orbit.[citation needed] ULA stated that approximately 95% of the hardware required for the Atlas HLV had already been flown on the Atlas V single-core vehicles.[citation needed]
A 2006 report, prepared by RAND Corporation for theOffice of the Secretary of Defense, stated that Lockheed Martin had decided not to develop an Atlas V heavy-lift vehicle (HLV).[26] 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,stockpile, or U.S. development of an RD-180 replacement."[27][needs update]
The lifting capability of the Atlas V HLV was to be roughly equivalent to theDelta IV Heavy. The latter utilizesRS-68 engines developed and produced domestically by Pratt & WhitneyRocketdyne.[28]
After December 2006, with the merger of Boeing and Lockheed-Martin space operations intoUnited Launch Alliance, the Atlas V program gained access to the tooling and processes for 18 ft (5.4 m) diameter stages used onDelta IV. An 18 ft 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 2009Augustine Report. An Atlas V PH2-Heavy (three 5 m stages in parallel; six RD-180s) along withShuttle-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.[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 degreeinclination.[29]The concept did not proceed onto full development, and was never built.
Review of U.S. Human Spaceflight Plans Committee
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