Atlas (rocket)

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The Atlas family of rockets
ICBM Atlas A
Mercury Atlas 9 on the launch pad
Atlas-Agena B at the start of Ranger 4
Atlas-Centaur at the start of Surveyor 1
Atlas I at the start of CRRES
Atlas II with the GOES-L weather satellite
Atlas IIAS on the SLC-2E launch pad in Vandenberg with the
Terra satellite
First start of an Atlas IIIA
Development stages of the atlas from Atlas II to Atlas V

The Atlas , once developed as a ballistic ICBM , is a launcher that was primarily used in the 1960s in the Mercury and Gemini programs. Further developments of the Atlas rocket are still in use today as launch vehicles for satellites and space probes .



Development of the Atlas began in March 1946 when the United States Army Air Forces commissioned Consolidated Vultee Aircraft Corporation to build an ICBM with a range of 8,000 km (Project MX-774 or Hiroc). The project was terminated after a short time due to lack of money, but revived in 1951 in view of the Soviet armament (as Project MX-1593 or Atlas). The first launch of an atlas took place on June 11, 1957. After a failure in the fuel system, the rocket had to be destroyed 51 seconds after launch. The first successful flight of an ICBM was reserved for the Soviet Union , with the successful launch of the R-7 on August 21, 1957.

The US Air Force but moved in the same year, by 17 December 1957 with the first successful flight of the Atlas A. A year later, on November 29, 1958, the Atlas B completed its first full-distance flight. In the same year it was decided to use the Atlas as a launcher for the Mercury program . In September 1959, the first Atlas D began service. In May 1960, the Atlas D set the record for the longest known ICBM flight with a flight distance of almost 14,500 km. Because of the long preparation time until the launch, the Atlas was decommissioned by the Air Force in 1965. It was replaced by the more militarily more suitable ICBMs Titan II and Minuteman . Discontinued ICBMs of the Atlas type were used as launch vehicles for small payloads until the 1990s.


  • Atlas A : Development model with only two engines, low fuel load, very simple control system and dummy rocket tip
  • Atlas B : development model with drive close to the later deployment configuration and detachable tip; the 10th rocket in this series put the first communications satellite Score into orbit
  • Atlas C : Development model close to the deployment configuration
  • Atlas D (Atlas LV-3B): first application model with Radio - inertial traffic control; First flight April 1959; first stationed at Vandenberg Air Force Base from September 1959 horizontally in bunkers; Warhead W-49 in Mk.2 / 3 RV (1.44 MT); retired in 1965; Use for NASA's Mercury program
  • Atlas E : Mission model with inertial control, improved refueling system and improved propulsion; Stationed horizontally in bunkers from 1961; Warhead W-47 in Mk.4 RV (3.75 MT); Retired in 1965, used as a launch vehicle with one or more solid upper stages until 1995
  • Atlas F : greatly improved model, stationed in silos from 1962; Warhead W-47 in Mk.4 RV (3.75 MT); retired in 1965; Used as a launch vehicle with one or more solid upper stages until 1981

1st generation space launch system

After the first launch of a converted Atlas-B as a satellite carrier, attempts were made to exploit the Atlas rocket's ability to carry heavier payloads. For this purpose, the Atlas-C was equipped with an Able upper stage and Altair third stage, each from the Vanguard rocket, and an attempt was made to use this combination to bring a 175 kg probe into a transfer orbit to the moon. Of this version, known as the Atlas-Able , only four were built, three of which were launched between November 15, 1959 and December 15, 1960. These three missiles failed, the fourth was not even launched because it exploded during a test on the launch pad.

Retired Atlas-D were used for the Mercury program . The first launch of such a Mercury Atlas rocket took place on July 29, 1960, but failed. After almost a year and a half and further test starts, the monkey Enos was successfully brought into orbit with the Mercury Atlas 5 on November 29, 1961 and successfully passed the dress rehearsal for the first manned flight. John Glenn completed this on February 20, 1962 as part of the Mercury 6 mission, making him the first American in an orbit . The three subsequent Mercury missions were also carried out with an Atlas rocket.

The Atlas with the Agena upper level launched numerous military and NASA payloads since 1960 . In the Gemini program , the Atlas-Agena also carried their Agena upper stage into orbit, which served as a docking target for the manned Gemini spaceships. There were six variants of this version (Atlas LV-3A Agena A, Atlas LV-3A Agena B, Atlas LV-3 Agena D, Atlas SLV-3 Agena D and Atlas SLV-3A Agena D) which are in the basic and upper school differentiated.

At the same time that the USAF was developing the Atlas-Agena A, NASA had a development program for a higher -powered Atlas-Vega for launching satellites and spacecraft. The Atlas-Vega would have had three steps for launching into higher orbits and escape orbits. Only the first two stages should be used for low-earth orbit takeoffs. The second stage was to receive a modified General Electric engine from the Vanguard first stage. The third stage, called Vega, was developed by the JPL. The development of the Atlas-Vega was stopped when the USAF developed the equally powerful Atlas-Agena-B. The Atlas Vega was never used.

The Atlas rocket was used in conjunction with the Centaur upper stage to launch the Surveyor moon probes, Mariner  9, Pioneer-Venus , Pioneer  10 and 11. In addition, this version, known as the Atlas Centaur LV-3C , launched commercial and military communications satellites into geotransfer orbit . There were also several versions of this rocket. In the original LV-3C version, an Atlas-D with a Centaur-C upper stage was used. Later the versions Atlas SLV-3C Centaur D, Atlas SLV-3C Centaur D1A and Atlas SLV-3C Centaur D1AR followed, whereby earlier versions of the Centaur and additional kick stages were used initially for tests and later for some launches.

An Atlas rocket with a smaller solid propellant upper stage was also used primarily by the military. This brought NOAA weather satellites and military payloads from Vandenberg AFB into polar orbit.

Space carrier system 2nd generation

In the 1980s, the Atlas could no longer keep up with the increased payload requirements, with the Ariane and Delta rockets making competition at the same time. So it was decided on the basis of the Atlas Centaur D-1AR to reinforce the base stage, which was lengthened by three meters and thus could hold 17 t more fuel. This version, known as the Atlas G Centaur , took off on its maiden flight on June 9, 1984, with the Intelsat V F-9 payload not reaching its orbit due to a bug in the Centaur upper stage and burning up a few months later. In total, this version was used seven times by 1989. The Atlas H , which was used five times for the launch of military radio reconnaissance satellites and consisted of the basic level of the Atlas G without the Centaur upper level, was also created on the basis of this rocket .

When it became clear after the Challenger disaster that an unmanned carrier system was needed to launch communications satellites and medium-weight military payloads ( Titan IV took over the heavy payloads , Delta II the lighter ones), the Atlas I , based largely on the Atlas G, was introduced in 1990 . At the same time, the development risk was transferred from NASA to the private manufacturer. From now on, the development of the rocket was no longer financed by NASA, but was subsidized indirectly through the booking of several rockets of the type to be developed by NASA and the Ministry of Defense . The main change compared to the Atlas G was the equipment with digital instead of analog control systems. The first of eleven starts took place on July 25, 1990, the last on April 25, 1997. The three false starts were caused twice by the turbopump of the Centaur upper stage and once by a reduction in performance in the basic stage.

The heavily revised, larger and somewhat stronger Atlas II followed a year later . It had improved engines in the first stage, structural reinforcements and some simplifications in construction, which greatly improved the reliability of the missile. This was followed by the commercial version Atlas IIA, which used an improved Centaur stage, and the Atlas IIAS, which also had four Castor IVA solid fuel boosters as starting aid and thus the payload to 8.6 t (LEO) or 3.63 t (GTO) increased. The Atlas II flew 63 missions between 1991 and 2004, all of which were successful.

The Atlas III (formerly called Atlas IIAR), initially planned as a further development of the Atlas II , was seen as a transitional solution to the Atlas V after the decision to develop the Atlas V. It was supposed to test a large part of the new technologies that would be used in the later Atlas V. The Atlas IIIA was the first US missile to use a Russian RD-180 main engine, which was derived from the engine of the Zenit missile. The much higher thrust of the RD-180 made the rocket heavier, and the tanks were considerably lengthened to hold more fuel. However, the controllable engine only worked at 74% of its full power during take-off, despite the higher weight, since otherwise the structure of the rocket would be overloaded, with acceleration values ​​above 5 g being achieved in the meantime. The first Atlas IIIA started on May 24, 2000, and the first Atlas IIIB on February 21, 2002. The Centaur of the Atlas III was designed so that it could be powered either with one (IIIA) or two (IIIB) RL-10 engines and a correspondingly shorter or longer tank (SEC = Single Engine Centaur, DEC = Dual Engine Centaur). This technology is also used in the Atlas V. Since the Atlas III was only a temporary solution, its production was discontinued after the introduction of the Atlas V. It completed only six launches (two IIIA and four IIIB) between May 2000 and February 2005, all of which were successful.

All second generation Atlas missiles were equipped with Centaur upper stages. Since the stage was a standard part of the rocket, its use was no longer specially marked as it was with the first-generation Atlas Centaur.

Further development

As a further development, the Atlas V was created , which made its maiden flight in 2002 and is described in a separate article because of the large differences. There was no Atlas IV, probably this number was skipped in order not to be confused with the Titan IV from the same manufacturer.


The Atlas of the first generation weighed around 116 tons at a height of 29.1 meters and could thus transport a payload of 1.4 tons. It was manufactured in a 1.5-stage design and consisted of a main and two additional start engines , the latter being dropped after approx. 130 s while the central main engine continued to work. This unusual stage concept ( "one and a half stage rocket" ), developed in the 1950s, arose from the fear that a rocket engine might not be able to reliably ignite during flight in the vacuum of space. Therefore, a concept was chosen in which all three engines were ignited on the ground. All engines were supplied from the same tanks. The silvery outer skin was made of stainless steel and, due to its wall only one millimeter thick, had to be stiffened by internal pressure when it was transported empty. The fuel was in the fuselage , i. H. not transported in two separate tanks, but in a tank with an insulated intermediate floor. Thanks to this design, the Atlas was characterized by an extremely low curb weight . The main engine was ignited at takeoff and burned for a total of 402 seconds, with the two launch engines assisting it for 131 seconds at the beginning. The fuel used was kerosene , which was kept in the tank at a pressure of 4.2 bar, and liquid oxygen , the tank overpressure of which was 2.1 bar , was used as the oxidizer . The Atlas was manufactured by Convair, the three engines were increased in performance over time. From the Atlas III onwards, however, they switched to a Russian engine with two combustion chambers and a significantly higher specific impulse and thrust.

Technical specifications

Atlas B Atlas D Atlas E / F Atlas Agena A Atlas Centaur Atlas 1 Atlas 2A Atlas 3B
length 26.0 m 25.0 m 29.2 m 30.1 m 35.2 m 43.77 m 47.42 m 53.10 m
span 4.90 m 4.88 m 4.90 m
diameter 3.05 m
Takeoff mass 110.7 t 116.1 t 122.0 t 124.0 t 136.1 t 164.3 t 187.7 t 225.5 t
stages 1.5 2.5
payload 70 kg (LEO) 1.36 t (LEO) 2.25 t (LEO) 2.30 t (LEO)
1.00 t (GTO)
0.50 t (ESC)
4.00 t (LEO)
1.80 t (GTO)
1.00 t (ESC)
3.63 t (LEO)
2.26 t (GTO)
7.28 t (LEO)
3.04 t (GTO)
10.7 t (LEO)
4.48 t (GTO)
Booster / 1st stage
Engine 2 XLR-89-5 2 LR-89-5 2 XLR-89-5 2 LR-89-5 2 LR-89-7 2 RS-56-OBA RD-180
Start thrust 1517 kN 1645 kN 1517 kN 1645 kN 2094 kN 3827 kN
fuel Kerosene and LOX
Burn time 120 s 135 s 120 s 174 s 172 s 145 s
Takeoff / empty mass ? / 3.05 t ? / 3.95 t ? / 3.175 t ? / 3.05 t ? / 3.18 t ? / 3.65 t ? / 4.19 t 195.6 / 13.73 t
Engine XLR-105-5 LR-105-5 XLR-105-5 LR-105-5 LR-105-7 RS-56-OSA
thrust 363 kN 386 kN 363 kN 386 kN
fuel Kerosene and LOX
Takeoff / empty mass 107.5 / 3.98 t 113.1 / 2.35 t 117.8 / 4.93 t 117.2 / 2.39 t 117.4 / 3.70 t 142.5 / 4.24 t 162.5 / 2.05 t
Burn time 240 s 303 s 309 s 250 s 335 s 266 s 283 s
length 21.9 m 21.2 m 20.7 m 20.3 m 18.3 m 22.2 m 24.9 m
diameter 3.05 m
2nd stage
Engine Thiokol TE-M-364-4 Bell XLR81-BA-5 P&W RL-10-A1 P&W RL-10A-3A P&W RL-10A-4 P&W RL-10A-4-2
thrust 66.7 kN 68.9 kN 71.2 kN 146.8 kN 185 kN 198.3 kN
fuel fixed (TP-H-3062) UDMH / nitric acid H2 and LOX
Takeoff / empty mass 1123/83 kg 3790/885 kg 15.6 / 2.0 t 15.6 / 1.7 t 15.6 / 2.1 t 22.96 / 2.1 t
Burn time 43.5 s 120 s 430 s 402 s 392 s 460 s
length 4.7 m 9.15 m 10.10 m 13.25 m
diameter 0.93 m 1.52 m 3.05 m

1st generation ICBM in comparison

Country USSR United States
rocket R-7 / R-7A R-16 / R-16U R-9A SM-65 Atlas (-D / -E / -F) SM-68 Titan I
developer OKB-1 ( Korolev ) OKB-586 ( Jangel ) OKB-1 (Korolev) Convair Glenn L. Martin Company
Start of development 1954/1958 1956/1960 1959 1954 1958
first operational readiness 1959/1960 1961/1963 1964/1964 1959/1961/1962 1962
Retirement until 1968 1976/1976 1976 1964/1965/1965 1965
Range (km) 8,000 / 9,500-12,000 11,000-13,000 12,500 10,000
control radio-inertial inertial radio-intertial radio-inertial / inertial radio-inertial / inertial
CEP (km) 10 4.3 8-10 <1.8
Takeoff mass (t) 280/276 141/147 80 118/122/122 103
stages 1.5 2 2 1.5 2
Fuel combination Kerosene / LOX UDMH / nitric acid Kerosene / LOX Kerosene / LOX Kerosene / LOX
Stationing type launch pad Launch ramp / silo Launch ramp / silo Launch ramp / bunker / silo silo
maximum overpressure ( psi ; protection of the starting system in the event of an explosion) k. A. / 28 k. A. / 28 k. A. / 25/100 100
reaction time about 24 h Ten minutes - several hours 20 min / 8-10 min 15-20 min 15-20 min
Warranty period (years at high alert) 30 days (fueled) 1 5
Explosive strength of the warhead ( MT ) 3-5 3-6 5 1.44 / 3.75 / 3.75 3.75
Max. stationed number 6th 186 23 30/27/72 54

See also

Web links

Commons : Atlas (rocket)  - album with pictures, videos and audio files

Individual evidence

  1. ^ A b On Mars: Exploration of the Red Planet. 1958-1978 NASA SP-4212 Chapter 2
  2. NASA SP-4210 LUNAR IMPACT: A History of Project Ranger, in NASA History online
  3. a b Eugen Reichl: The rocket type book . 1st edition. Motorbuch, Stuttgart 2007. ISBN 3-613-02788-7
  4. a b c P. Podvig (Ed.): Russian Strategic Nuclear Forces. MIT Press, 2004, ISBN 978-0-262-16202-9 .
  5. a b c S. J. Zaloga : The Kremlin's Nuclear Sword - The Rise and Fall of Russia's Strategic Nuclear Forces, 1945-2000. Smithsonian Institution Press, 2001, ISBN 1-58834-007-4 .
  6. a b c d e Nuclear Notebook: US and Soviet / Russian intercontinental ballistic missiles, 1959–2008
  7. ^ A b David Stumpf Titan II - A History of a Cold War Missile Program . University of Arkansas Press, 2000. ISBN 1-55728-601-9