Atlas (rocket family)
|Atlas II, III and V comparison|
|Role||Expendable launch system with various applications|
United Launch Alliance
|First flight||17 December 1957|
|Status||Atlas V (current)|
|Primary users||United States Air Force
National Aeronautics and Space Administration
Atlas is a family of United States missiles and space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics, to be used as an intercontinental ballistic missile (ICBM). It was a liquid-fuel rocket burning liquid oxygen and RP-1 in three engines configured in an unusual "stage-and-a-half" or "Parallel Staging" design: its two outboard booster engines were jettisoned during ascent, while its center sustainer engine, fuel tanks and other structural elements were retained into orbit.
The missiles saw only brief ICBM service, and the last squadron was taken off operational alert in 1965. From 1962 to 1963, Atlas boosters launched the first four American astronauts to orbit the Earth. Various Atlas II models were launched 63 times between 1991 and 2004. There were only six launches of the Atlas III, all between 2000 and 2005. The Atlas V is still in service, with launches planned until 2020.
The Atlas name was originally proposed by Karel Bossart and his design team working at Convair on project MX-1593. Using the name of a mighty god of Greek mythology reflected the missile's place as the biggest and most powerful to date. It also reflected the parent company of Convair, the Atlas Corporation.
- 1 Variants
- 2 See also
- 3 References
- 4 Further reading
- 5 External links
SM-65 Atlas missile
The first successful test launch of an SM-65 Atlas missile was on December 17, 1957. Approximately 350 Atlas missiles were built. Many were eventually converted to orbital launch vehicles after they were removed from service as missiles.
Early Atlas rockets were also built specifically for non-military uses. On December 18, 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 satellite broadcast President Eisenhower’s pre-recorded Christmas message around the world.
The Atlas boosters would collapse under their own weight if not kept pressurized with nitrogen gas in the tank, even when not fueled. The Atlas booster was unusual in its use of balloon tanks for holding its fuel. 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.
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 the early "Block I" GPS satellites.
Atlas boosters were also used for the last four manned Project Mercury missions, the first United States manned 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 manned Mercury orbital missions from 1962 to 1963.
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 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 the Launch Complex 36 at Cape Canaveral Air Force Station, Florida. A specially-enhanced[how?] version of the Atlas D vehicle for mating with Centaur stages; the Atlas's engines were upgraded and the structure reinforced for the large upper stage, along with elongated fuel tanks.
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.
Launch vehicles based on original Atlas ICBM
|Model name||First launch||Last launch||Total launches||Successes||ICBM base||Upper stage||Notable payloads||Remarks|
|Atlas-Vega||-||-||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)||Altair||none||2 rockets failed during static firing, and 3 during attempts to launch Pioneer spacecrafts to the Moon|
|Atlas LV-3A||1960||1968||49||38||Atlas D||Agena||Mariner 2, Ranger program, Missile Defense Alarm System||The baseline Atlas-Agena sub-family vehicle|
|Atlas LV-3B||1959||1962?||9||9||Atlas D||none||Mercury-Atlas 1||Man-rated Atlas LV-3A|
|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 2.97 m|
|Atlas SLV-3B||1966||1966||1||1||Atlas D||Agena D||Orbiting Astronomical Observatory 1|
|Atlas LV-3C||1963||1967||11||8||Atlas D||Centaur C||?||The baseline Atlas-Centaur sub-family vehicle|
|Atlas SLV-3C||1967||1972||17||14||Atlas D||Centaur D||?||Same as LV-3C stretched 1.3 m|
|Atlas SLV-3D||1973||1983||32||29||Atlas D||Centaur D1A||?||Same as SLV-3C except Centaur uprated and Atlas electronics integrated with Centaur|
|Atlas G||1984||1987||6||4||Atlas G||Centaur D1A||?||Same as SLV-3D but Atlas longer by 2.06 m|
|Atlas I||1990||1997||11||8||Atlas G derived||Centaur D1A derived||CRRES||Same as Atlas G except strengthened for 4.27 m payload fairing and ring laser gyro added.|
|Atlas II||1991||1998||10||10||Atlas G derived||Centaur D1A derived||Eutelsat||Same as Atlas I except Atlas stretched 2.74 m, engines uprated, added hydrazine roll control, fixed foam insulation, deleted verniers, and Centaur stretched 0.9 m. Development done by General Dynamics (now Lockheed Martin).|
|Atlas IIA||1992||2002||23||23||Atlas G derived||Centaur D1A derived||-||Same as Atlas II except Centaur RL10 engines uprated to 88 kN of thrust and 6.5 Isp increase from extendible RL10 nozzles|
|Atlas IIAS||1993||2004||30||30||Atlas G derived||Centaur D1A derived||-||Same as Atlas IIA except 4 Castor IVA strap-on boosters added|
|Atlas D Space||1965||1967||7||6||Atlas D||none||?||ICBM refurbished for orbital launch|
|Atlas E Space||1980||1995||23||21||Atlas E||none||?||ICBM refurbished for orbital launch|
|Atlas F Space||1968||1981||23||22||Atlas F||none||?||ICBM refurbished for orbital launch|
|Atlas H Space||1983||1987||5||5||Atlas D||Centaur stage removed||?||ICBM refurbished for orbital launch, Atlas D upgraded with Atlas E/F avionics|
The Atlas III was a major revised version from Atlas II, which both dropped balloon tank design, together with the 1.5 stage in previous Altas family. It is the first Atlas rocket that adopted Russian-designed RD-180 engine at the first stage.
The newest version of Atlas, the Atlas V, is an Atlas in name alone, as it contains little Atlas technology. It no longer uses balloon tanks nor 1.5 staging, but incorporates a rigid framework for its first-stage booster, much like the Titan family of vehicles. The rigid fuselage is heavier, but easier to handle and transport, eliminating the need for constant internal pressure.
The Atlas V is an active expendable launch system in the Atlas rocket family. The Atlas V was developed, as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program, and formerly operated by Lockheed Martin. It is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance. The first Atlas V was launched on August 21, 2002 from Cape Canaveral Air Force Station. Launches are from Space Launch Complex 41 at Cape Canaveral Air Force Station and Space Launch Complex 3-E at Vandenberg Air Force Base. The Atlas V family uses a single-stage Atlas main engine, the Russian RD-180, burning kerosene and liquid oxygen, and the newly developed Common Core Booster (CCB) with up to five Aerojet Rocketdyne made strap-on solid rocket boosters. A single or dual American-made RL10A-4-2 (also Aerojet Rocketdyne) burning liquid hydrogen and liquid oxygen is used to power the Centaur upper stage.
Lockheed Martin Commercial Launch Services continues to market the Atlas V to commercial customers worldwide.
The Atlas III and Atlas V use Russian-designed/built NPO Energomash RD-180 engines. These engines are now prepared for production under license by RD AMROSS in the United States. The Atlas V is built in Denver, Colorado by United Launch Alliance, a joint venture of Lockheed Martin and Boeing. Future[when?] production will be shifted to Decatur, Alabama.
The US Congress passed legislation in December 2014 that would prevent the award of any additional launch contracts for military launches to vehicles that use Russian engines. Since the Atlas V uses the Russian RD-180 engines on its first stage, this will curtail Atlas V military satellite launches after the current supply of engines is used up.
|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||1xRL-10A||Eutelsat W4||major revision of Atlas IIA, with new RD-180 first-stage engine, normal staging, first stage stretched 4.4 m and strengthened.|
|Atlas IIIB||2002||2005||4||4||1xRD-180||2xRL-10A||Same as Atlas IIIA, except for dual-engine Centaur stage and Centaur stretched 1.7 m.|
|Atlas V 400||2002||-||25||24||1xRD-180||1xRL-10A||major revision of Atlas IIIA, with new first-stage structure (CCB).|
|Atlas V 500||2003||-||12||12||1xRD-180||1xRL-10A||major revision of Atlas V 400, with optional solid strap-on boosters, and Centaur stage encapsulated inside 5.4 m payload fairing.|
Proposed future developments
Atlas V successor
Geopolitical and US political considerations in 2014 led to an effort by ULA to consider the possible replacement of the 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/methane engine to replace the RD-180 on a new first stage booster. The engine is already in its third year of development by Blue Origin, and ULA expects the new stage and engine to start flying no earlier than 2019. Two of the 2,400-kilonewton (550,000 lbf)-thrust BE-4 engines will be used on the new launch vehicle booster.
In October 2014, ULA announced a major restructuring of processes and workforce in order to decrease launch costs by half. One of the reasons given for the restructuring and new cost reduction goals was competition from SpaceX. ULA intends to have preliminary design ideas in place for a blending of the Atlas V and Delta IV technology by the end of 2014, to build a successor that will allow them to cut launch costs in half. A part of the restructuring effort is to co-develop the alternative BE-4 engine for the new launch vehicle.
Although the rocket remains unnamed, ULA first referred to this vehicle as a "next generation launch system" in October 2014.
In the decade since ULA was formed from Lockheed Martin and Boeing, there have been a number of proposals and concept studies of future launch vehicles. None have been 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 would use three Common Core Booster (CCB) stages strapped together to provide the capability necessary to lift 25 tonne payload to low Earth orbit. Approximately 95% of the hardware required for the Atlas HLV has already been flown on the Atlas V single core vehicles.
A report, prepared by RAND Corporation for the Office of the Secretary of Defense in 2006, 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, Stockpile, or U.S. development of an RD-180 replacement."
The lifting capability of the Atlas V HLV is roughly equivalent to the Delta IV Heavy. The latter utilizes RS-68 engines developed and produced domestically by Pratt & Whitney Rocketdyne.
Atlas Phase 2
Since 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-meter-diameter stages, used on Delta IV. At 5 meters, a stage can accept dual RD-180 engines.[clarification needed]
The conceptual heavy-lift vehicle was called "Atlas Phase 2" or "PH2" in the 2009 Augustine Report 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 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.
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- "HSF Final Report: Seeking a Human Spaceflight Program Worthy of a Great Nation" (PDF). October 2009. p. 64. Retrieved 2011-02-07.
Review of U.S. Human Spaceflight Plans Committee
- Gainor, Christopher, “The Atlas and the Air Force: Reassessing the Beginnings of America’s First Intercontinental Ballistic Missile,” Technology and Culture 54 (April 2013), 346–70.