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45-563: 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 engines, and the option for strap-on solid rocket boosters. It was designed to launch payloads into low Earth orbit , geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of

90-465: A Medium fairing could move the most payload to orbit, as that fairing was the lightest. Similarly, rockets with Large or Extended fairings suffered slight hits to their payload capacity. Atlas II was developed into three versions. The original Atlas II was based on the Atlas I and its predecessors . Its lengthened propellant tanks and improved electronics over the Atlas I offered better performance. It

135-550: A common bulkhead, which helped keep mass down. Centaur II was 10.1 m (33 ft) long, carrying almost 17 t (37,000 lb) of fuel. The stage also featured 12 27 N (6.1 lbf) hydrazine thrusters to orient the stage and settle the propellants prior to engine ignition. For the IIA and IIAS versions, Atlas used the Centaur IIA variant which featured 2 RL-10A -4 engines, providing higher thrust and efficiency over

180-551: A comsat for the Air Force. Atlas boosters were also used for the last four crewed Project Mercury 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

225-543: A half vehicles were used during Project FIRE 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 , but Atlas launches continued until 2004, when the last "classic" Atlas with balloon tanks and the jettisonable booster section launched

270-602: 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- inclination . The concept did not proceed onto full development, and was never built. RL-10A Too Many Requests If you report this error to the Wikimedia System Administrators, please include

315-665: Is built in Decatur, Alabama , and maintains two launch sites: Space Launch Complex 41 at Cape Canaveral Space Force Station and Space Launch Complex 3-E at Vandenberg Space Force Base . 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

360-567: 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. In 2014, US Congress passed legislation restricting the purchase and use of the Russian-supplied RD-180 engine used on

405-657: Is still in service, with launches planned into the mid 2020s. More than 300 Atlas launches have been conducted from Cape Canaveral Space Force Station in Florida and 285 from Vandenberg Space Force Base in California. The Atlas was used as an expendable launch system , with both the Agena and Centaur upper stages, for the Mariner space probes used to explore Mercury , Venus , and Mars (1962–1973); and to launch ten of

450-556: The Launch Complex 36 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 1982 art film Koyaanisqatsi , directed by Godfrey Reggio . Beginning in 1963,

495-588: The MA-5A and shared a common gas generator . They burned for approximately 164 seconds before being jettisoned, when acceleration reached approximately 5.0–5.5  g . The central sustainer engine on the first stage, an RS-56-OSA, would burn for an additional 125 seconds after their jettison. It featured better efficiency at high altitudes than the RS-56-OBAs. The first stage also had the option to be fitted with 4 Castor 4A solid rocket boosters as part of

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540-532: The Mercury program missions (1962–1963). 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

585-639: 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. Each of the Agena target vehicles used for the later space rendezvous practice missions of Gemini was launched on an Atlas rocket. The Atlas-Centaur was an expendable launch system derived from the SM-65D Atlas missile. Launches were conducted from two pads of

630-635: 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. Following retirement as an ICBM, the Atlas-E, along with the Atlas-F , was refurbished for orbital launches. The last Atlas E/F spacecraft launch

675-712: 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." 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 . After December 2006, with

720-649: 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 . The Atlas V Heavy was a ULA concept proposal that would have used three Common Core Booster (CCB) stages strapped together to provide

765-777: The Atlas II vehicle, primarily to launch Defense Satellite Communications System payloads under the Medium Launch Vehicle II (MLV-II) program. Additional commercial and U.S. Government sales resulted in production increases leading to greater than 60 vehicles being produced and launched. Atlas II was developed from the Atlas I and featured numerous upgrades over that vehicle. Atlas II was launched from Launch Complex 36 at Cape Canaveral Space Force Station in Florida as well as Space Launch Complex 3E at Vandenberg Space Force Base in California. All launches were successful. Atlas II provided higher performance than

810-500: The Atlas II: The Medium variant was not commonly used for Atlas II but was often used in earlier Atlas rockets. The Large and Extended fairing options were also later used on the Atlas III and Atlas V rockets. For the Atlas V, these fairings were part of the 400-series of that rocket, and a further extended option ("Extra Extended") was available. The 4-meter Atlas fairing last flew in 2022. Atlas II rockets flying with

855-546: The Atlas as a satellite launcher. Atlas D missile-derived SLV-3s were used for orbital launches with the RM-81 Agena and Centaur upper stages. The modified Atlas LV-3B was used for the orbital element of Project Mercury , launching four crewed Mercury spacecraft into low Earth orbit . 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 . Two suborbital stage and

900-535: The Atlas ;II, IIA and IIAS models were carried out between 1991 and 2004; all sixty-three launches were successes, making the Atlas II a highly reliable space launch system. The Atlas line was continued by the Atlas III , used between 2000 and 2005, and the Atlas V , which is still in use as of 2024. In May 1988, the US Air Force chose General Dynamics (now Lockheed Martin ) to develop

945-553: The Centaur V flying on the Vulcan rocket will only utilize two RL-10 engines. The Integrated Apogee Boost Stage was an optional upper stage, used only as an apogee kick stage when launching Defense Satellite Communications System III satellites (which were designed to be delivered directly to geostationary orbit using the Transtage or Inertial Upper Stage , and so were not capable of performing their own circularization burn at

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990-422: The Centaur upper stage. Centaur II featured 2 RL-10A -3-3A engines, burning liquid hydrogen and liquid oxygen. It featured propellant tanks 0.9 meters longer than its predecessor, Centaur I, giving the stage more propellant and therefore higher performance. Due to the super cold propellants inside Centaur, foam insulation was installed onto the outer metal skin on the stage to help mitigate propellant boiloff inside

1035-598: The Defense Meteorological Satellite Program. 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. The Atlas V, currently in service, was developed by Lockheed Martin as part of

1080-518: The IIAS version, each providing an additional 478.3 kN (107,500 lb f ) of thrust for 56 seconds. The first two boosters were ignited at liftoff, and the other two were ignited after the first two burnt out. Both pairs of boosters were jettisoned shortly after their respective burns. The second stage of Atlas II, the Centaur II, was the result of over 3 decades of flights and enhancements of

1125-565: The RL-10A-3-3A. The two engines could be fitted with extendable nozzles, which would provide an increase in efficiency and therefore performance. Centaur II was further refined to create the Centaur III, which flew on the Atlas III and continues to fly today on the Atlas V . Atlas II was the final Atlas rocket that only had a dual-engine Centaur available, future rockets had the option for one or two RL-10 engines on Centaur. However,

1170-548: 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

1215-494: The apogee of their geostationary transfer orbit ) on board the Atlas II and, later, the Delta IV . It was powered by two R-4D engines and could operate on-orbit for up to twelve days before deploying its payload, allowing additional flexibility in mission planning. The IABS measured 2.9 m in diameter, and 0.68 m in length, carrying 1303 kg of propellant with a dry mass of 275 kg. Three fairing models were available for

1260-479: The award of further military launch contracts to vehicles that use Russian-made engines was approved by the 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. Prior to

1305-769: 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. Atlas was also used throughout the mid-1960s to launch the Agena Target Vehicles used during the Gemini program . Beginning in 1960, the Agena upper stage , powered by hypergolic propellant , was used extensively on Atlas launch vehicles. The United States Air Force , NRO and CIA used them to launch SIGINT satellites. NASA used them in

1350-589: The capability necessary to lift 25 tonne payload to low Earth orbit . 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

1395-480: The earlier Atlas I by using engines with greater thrust and longer propellant tanks for both stages. The increased thrust, engine efficiency, and propellant capacity enabled the vehicle to lift payloads of 6,100 pounds (2,767 kg) into geostationary transfer orbit (GTO), or more on later Atlas II variants. Atlas II also featured lower-cost electronics, an improved flight computer, and longer propellant tanks than its predecessor, Atlas I . The Atlas II first stage

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1440-473: The early "Block I" GPS satellites . 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 , and the first test of any satellite for direct practical applications." The communications payload

1485-512: The first four US astronauts to orbit the Earth (in contrast to the preceding two Redstone suborbital launches). The Atlas-Agena and Atlas-Centaur satellite launch vehicles were also derived directly from the original Atlas. The Atlas-Centaur was evolved into the Atlas II , 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

1530-514: 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 / methane engine to replace the RD-180 on the new Vulcan rocket . The new stage and engine first flew in 2024. In December 2014, legislation to prevent

1575-529: 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 Augustine Report . An Atlas V PH2-Heavy (three 5 m stages in parallel; six RD-180s) along with Shuttle-derived , Ares V and Ares V Lite, were considered as

1620-407: The tank. Centaur II's foam insulation was permanently attached to the side of the stage, whereas previous versions of the stage (including Centaur I) jettisoned their insulation panels during flight. The Centaur II upper stage (along with all other Centaur variants) used a pressure-stabilized propellant tank design and cryogenic propellants . The two stainless steel propellant tanks were separated by

1665-478: The vehicle's roll. Compared to Atlas I , the Atlas II ;first stage was 2.7 m (8 ft 10 in) taller. The Atlas II was the last Atlas rocket to use the "stage-and-a-half" technique, where it ignited all 3 RS-56 engines at liftoff and then jettisoned the 2 RS-56-OBA side engines and their support structure during ascent. The two RS-56-OBA engines were integrated into a single unit called

1710-697: Was 3.05 m (10.0 ft) in diameter and 24.90 m (81.7 ft) long. The stage was powered by 3 RS-56 rocket engines (derived from the RS-27 main engine of the Delta ;II rocket) burning 156 t (344,000 lb) of RP-1 and liquid oxygen . The two booster engines were the RS-56-OBA variants (the complete assembly of both engines and the aft skirt was referred to as the MA-5A), with high thrust but moderate efficiency. The sustainer (center) engine

1755-457: 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

1800-495: Was designed to work as part of the US Air Force's Medium Launch Vehicle II program. This version flew between 1991 and 1998. Atlas IIA was a derivative of the Atlas II designed to service the commercial launch market. The main improvement was the switch from the RL10 A-4 engine on the Centaur upper stage, increasing the stage's performance and the vehicle's payload capability. The IIA version flew between 1992 and 2002. Atlas IIAS

1845-425: Was largely identical to IIA, but added four Castor 4A solid rocket boosters to increase performance. These boosters were ignited in pairs, with one pair igniting on the ground, and the second igniting in the air shortly after the first pair separated. The "half-stage booster section would then drop off as usual. IIAS was used between 1993 and 2004, concurrently with IIA. Atlas (rocket family) The Atlas name

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1890-538: Was originally proposed by Karel Bossart and his design team working at Convair 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 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

1935-407: Was placed into low 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

1980-511: 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 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 "space boosters" were used to launch

2025-459: Was the RS-56-OSA variant, featuring much less thrust but higher efficiency at high altitudes than the booster engines. The vernier engines used on the first stage of the Atlas I (and all previous Atlas models) were replaced by a hydrazine -fueled roll control system on Atlas II. This system, mounted on the interstage between the first and second stages, utilized small thrusters to control

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