Atlas (rocket family)

Atlas family
Atlas EELV family.png
Atlas II, III and V comparison
RoleExpendable launch system with various applications
ManufacturerConvair
General Dynamics
Lockheed Martin
United Launch Alliance
First flight17 December 1957[1]
Introduction1957
StatusAtlas V (current)
Primary usersUnited States Air Force
National Aeronautics and Space Administration
Produced1957–2010s (decade)
VariantsSM-65 Atlas
SM-65D Atlas
Atlas LV-3C
Atlas IIIA
Atlas V

Atlas is a family of American missiles and space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics,[2] to be used as an intercontinental ballistic missile (ICBM). It was a liquid propellant rocket burning liquid oxygen and RP-1 fuel 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, propellant tanks and other structural elements were retained through orbital insertion (for orbital flights).

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 whereas Redstone preceded Atlas with two sub-orbital launches. 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 titan from 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.[3]

More than 300 Atlas launches have been conducted from Cape Canaveral Air Force Station in Florida and 285 from Vandenberg Air Force Base in California.

Variants

SM-65 Atlas missile

Launch of an Atlas B ICBM

The first successful test launch of an SM-65 Atlas missile was on December 17, 1957.[1] 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."[4][5] 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 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 penetrating 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 the early "Block I" GPS satellites.[6]

Mercury program

Launch of the first American manned orbital spaceflight

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.

Atlas-Agena

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.[7] 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.

Atlas-Centaur

The Atlas-Centaur was an expendable launch system derived from the SM-65D Atlas missile.[citation needed] 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 propellant 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[8] - - 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)[9] 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[10] 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[11] 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 part of 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[citation needed] Centaur D1A derived - Same as Atlas IIA except 4 Castor IVA strap-on boosters added
Atlas D-OV1 1965 1967 7 6 Atlas D none ? ICBM refurbished for orbital launch
Atlas E 1980 1995 23 21 Atlas E none ? ICBM refurbished for orbital launch
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 ? Atlas G modified for West Coast Avionics

SLC 3E modified for Space Booster hold down system versus weapon system flyaway

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.[12]

Atlas V

Launch of an Atlas V 401 carrying the LRO and LCROSS

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 continues to market the Atlas V to commercial customers.[13] Atlas V is built in Decatur, Alabama and maintains two launch sites: Space Launch Complex 41 at Cape Canaveral Air Force Station and Space Launch Complex 3-E at Vandenberg Air 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 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 RL10A-4-2 engines.[14]

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 bill allows ULA to continue to use the 29 RD-180 engines already on order at the time.[15]

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 major revision of Atlas IIA, with new RD-180 first-stage engine, normal staging, first stage stretched 4.4 m and strengthened. First single RL10 engine Centaur.
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 - 25 24 1xRD-180 1xRL10A major revision of Atlas III, with new first-stage structure (CCB) and with optional solid strap-on boosters.
Atlas V 500 2003 - 12 12 1xRD-180 1xRL10A revision of Atlas V 400, with optional solid strap-on boosters, and Centaur stage encapsulated inside 5.4 m payload fairing.

RD-180 phaseout

In 2014, US Congress passed legislation restricting the purchase and use of the Russian-supplied RD-180 engine used on the first stage booster of the Atlas V.[16] Formal study contracts were issued in June 2014 to a number of US rocket engine suppliers.[17]

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.[17]

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