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Space


Atlas

Variants(1)

SM-65E/CGM-16E Atlas E(2) - The test firing of the Atlas E ICBM took place in October 1960. It met all test objectives by May 1961. The Atlas E used MA-3 engines on the booster and the sustainer. The original Atlas E vehicles, which stood deployed on alert in the 1960s, were completely overhauled for use as space launch vehicles. Known as the "Wheat Field" Atlas, refurbished Atlas E vehicles were launched from Vandenberg for NASA and USAF missions.

The boosters are shipped to Vandenberg AFB, California, for modification and launch by General Dynamics Space Systems Division as needed. Atlas E is capable of boosting a 4,000-pound payload to a 450-nmi orbit. Atlas E is 67 feet long, and 92 feet long with a payload shroud. The Atlas is 10 feet in diameter, with a payload fairing diameter of 7 feet. Weight at liftoff is 278,000 pounds.

Atlas E is a stage-and-a-half, liquid-fueled rocket consisting of a cluster of three Rocketdyne MA-3 engines (two boosters and one sustainer) and two small vernier engines. The propellant is a combination of liquid oxygen and RP-1, a highly refined kerosene. All engines are ignited on the ground and brought up to approximately full thrust before vehicle launch. The Atlas E provides a total thrust of from 388,000 to 392,000 pounds.

All Atlas engines are ignited prior to liftoff. At approximately 2 minutes into the flight the two booster engines are jettisoned and the sustainer engine continues to burn until cutoff at approximately 5 minutes 21 seconds into flight, followed by payload separation at 5 minutes 46 seconds. An airborne autopilot programmer in the launch vehicle flight control system provides preprogrammed steering and backup discrete commands. The General Electric Radio Tracking System (GERTS) ground system acquires the vehicle at approximately liftoff + 85 seconds and performs the guidance function by means of the launch vehicle's pulse beacon decoder.

SM-65F/HGM-16F Atlas F - Testing of the Atlas F ICBM began in August 1961 with completion coming by the end of 1962. This marked the end of the five-year missile test program. As with the Atlas E, many were subsequently used for space launch operations. The Atlas F used MA-5 engines on the booster and the sustainer.

Atlas/Agena - The Atlas/Agena combination was a series multipurpose two-stage liquid propellant rocket. It was used to place unmanned spacecraft in Earth orbit, or inject them into the proper trajectories for planetary or deep space probes. The programs in which the versatile Atlas/Agena was used included early Mariner probes to Mars and Venus, Ranger photographic missions to the Moon, the Orbiting Astronomical Observatory (OAO), and early Applications Technology Satellites (ATS). The Agena upper stage also was used as the rendezvous target vehicle for the Gemini spacecraft during this series of two-man missions in 1965-1966. In preparation for the manned lunar landings, Atlas/Agena launched lunar orbiter spacecraft which went into orbit around the Moon and took photographs of possible landing sites. The Atlas/Agena stood 36.6 meters (120 feet) high, and developed a total thrust at liftoff of approximately 1,725,824 newtons (288,000 pounds). It was last used in 1968 to launch an Orbiting Geophysical Observatory (OGO).

Atlas G(3) - Atlas G/Centaur D-IA combination was an improved version of the Atlas SLV-3D/Centaur D-IA configuration. The Atlas G was 81 inches longer than its predecessor. It also incorporated a booster thrust increase of 7,500 pounds leading to a vehicle liftoff thrust of 438,000 pounds. The vehicle became operational on the AC-62 INTELSAT V flight in June 1984. Atlas G has a constant ten-foot diameter tank up to the attach point of the interstage adapter. Total length from forward bulkhead tangency point rearward is 72.7 feet. Equipment is mounted within a pod on the side. A helium pressure system maintains structural integrity and turbopump pressure head during flight.

All Atlas engines of the Rocketdyne MA-5 propulsion system are ignited before liftoff. The two booster engines and the single sustainer engine share the same propellant tanks. The booster engines are jettisoned about two and half minutes into flight after 5.3g acceleration is attained. The sustainer burns until propellant depletion. Two small vernier rockets assist in the early roll maneuver to the desired azimuth and provide roll control during the sustainer phase. Propellants for all engines are LO2 and RP-l.

The Centaur D-lA, used in conjunction with Atlas G, incorporates the following improvements: elimination of hydrogen peroxide boost pumps in the propellant supply system, replacement of hydrogen peroxide reaction control system with an equivalent hydrazine system, incorporation of a silver throat cast insert in the Pratt & Whitney engines (new designation: RL 10A-3-3A).

The Atlas G/Centaur had the capability of launching spacecraft weighing 2,360 kg to geosynchronous altitude from the Eastern Test Range (ETR) at Cape Canaveral, Florida. As of late 1986, General Dynamics was under contract to deliver Atlas/Centaur vehicles through AC-68, which extended production into 1987. Firm launches were scheduled into 1987, with new launch dates available in 1989.

Atlas H(4) - The Atlas H booster, a radio-guided version of the Atlas that boosts Centaur, was used to launch US government missions from the Western Test Range (WTR) at Vandenberg AFB. California. The Atlas H weighed 132,723 kilograms at lift-off and generated 1,948 kilonewtons of thrust.

Atlas LV-3A(5) - Early space launch the LV-3A series were direct derivatives of the radio-inertial guided Atlas D ICBM. Each LV-3A vehicle was tailored to meet specific mission requirements. The life cycle of the LV-3A series spanned a period of approximately six years, ending in 1964.

LV-3A vehicles were superseded by the standardized SLV-3. Most of the early LV-3 series space boosters were modified versions of Atlas D weapon system vehicles, each adapted to its mission requirements. To satisfy each separate mission requirement, these space launch vehicles required individual tailoring of the vehicle structure and subsystems. Some required only minor changes-some required significant modifications. Lead times were necessarily long due to this program tailoring. Program realignments and cancellations caused extensive launch, vehicle storage or re-allocation which, in turn, resulted in launch-vehicle modification due to updating and/or mission-peculiar requirements. This detracted from the inherent flexibility, reliability, and low cost of the Atlas.

On 20 February 1962, the free world's first earth-orbiting Astronaut, Colonel John Glenn, was placed in orbit by an Atlas LV-3B, the first of four such manned flights. Mercury program launch vehicles, designated the LV-3B series, were man-rated derivations of the Atlas D used for the first American manned orbital missions. The Mercury program hardware, both launch vehicle and spacecraft, performed so successfully that two LV-3B vehicles remained in the inventory after all Mercury program objectives were achieved. The success of the much-heralded Mercury Program was typical of the reliability achievements of the space programs in which the Atlas was a participant.

LV-3C vehicles launched Centaur vehicles, including the Surveyor I lunar soft-landing mission. These vehicles were constant 10-foot-diameter tank derivatives of the Atlas D, with the guidance system removed and the guidance pod shortened. Atlas vehicles with a Centaur second stage use the all-inertial guidance system on-board the Centaur.

Atlas SLV-3(6) - The increasing demand for space launch vehicles for a broad variety of US Air Force and NASA programs, coupled with the very high reliability which these programs demand, led to the decision to develop a standard space launch vehicle with improved countdown and flight reliability, increased flexibility for mission assignments, shorter launch-site turnaround time, and lower cost. This decision resulted in a contract awarded in 1962 for the design and production of the Atlas SLV-3.

The Atlas SLV-3 series had a tapered forward tank section for use with small-diameter second stages, or a cylindrical forward section (10-foot diameter mating ring) for use with the 10-foot diameter Centaur upper stage. SLV-3 and SLV-3A are of the tapered-tank configuration. SLV-3C had the cylindrical forward tank, as did the LV-3C and SLV-3(0AO) which are no longer in production. An Agena second stage could be used for large-diameter payloads by utilizing the SLV-3B (systems from SLV-3A; tank from SLV-3C) and the OAO fairing system.

Atlas SLV-3A(7) - By early 1965, growing payload requirements dictated the development of space boosters with increased performance characteristics. Convair division submitted proposals to the Air Force for a number of uprated Atlas configurations. Each of these proposed configurations was based on extending the length (and therefore propellant capacity) of the Atlas monocoque tanks, increasing the engine thrust, and reducing overall vehicle weight. As the result of these proposals, contractual authorization was received for design, development, and fabrication of two uprated Atlas space launch vehicle configurations, the SLV-3A and the SLV-3C, to provide increased performance capability for Atlas/Agena and Atlas/Centaur missions, respectively. The first SLV-3A and SLV-3C were delivered to the Air Force in 1967.

SLV-3A vehicles were improved-performance versions of SLV-3, featuring an elongated tank (117-inch extension) and an uprated propulsion system.

The airframe is composed of two major sections: the sustainer or tank section and the booster section. The sustainer section consists of the fuel tank, liquid oxygen tank, and the pods. The sustainer and vernier engines are mounted on this structure. The booster section is composed of the thrust cylinder, engine nacelles, heat shield, and fairings. The booster engines are mounted in this section. The propellant tank is the primary structure of the sustainer section. It is a thin-wall, fully monocoque-structure pressure vessel, deriving its rigidity from internal pressurization. The tank body of the SLV-3 is a resistance-welded structure of corrosion-resistant stainless steel sheets (skins) which vary in thickness from 0.048 to 0.015 in.

SLV-3A maintained the same tank shape as the SLV-3 at its forward and aft ends. However, additional skin sections are welded into the cylindrical section of the tank to make the total tank length 117 inches longer than the SLV-3. The intermediate bulkhead was positioned such that the fuel/oxidizer ratio remained the same for both vehicles. Propellant capacity of SLV-3A was increased approximately 48,000 pounds over the SLV-3 by the increased oxidizer and fuel tank volumes.

The LV-3C was superseded by the uprated and standardized SLV-3C, which had a 51-inch longer propellant tank than LV-3C and the same uprated propulsion system as the SLV-3A. SLV-3C had a different forward-tank shape than the standard SLV-3. Like the LV-3C, the SLV-3C had a constant 10-foot-diameter tank to the forward mating ring, and an ellipsoidal forward bulkhead. The cylindrical tank section of SLV-3C was 51 inches longer than LV-3C. The intermediate bulkhead was relocated (forward) to retain the propellant ratio. Approximately 21,000 pounds more propellants were accommodated by the SLV-3C than the LV-3C.

Atlas SLV-3D - The SLV-3D series was developed for use with the Centaur D-1A and D-1AR vehicles.

Further Capabilities

Recognizing the trend toward larger and heavier spacecraft designs, General Dynamics in 1986 began evaluating an Atlas K/Centaur with increased performance and a 4.0 meter diameter fairing.(8)

The Atlas-Centaur had a lift capacity to LEO of about 13,300 pounds or about 5,100 pounds to geosynchronous transfer orbit. The Atlas-Centaur II was expected to have an ability to launch 16,150 pounds to LEO, or about 6,100 pounds to geosynchronous transfer orbit. The performance enhancement of almost 3,000 pounds to LEO was to be achieved by increasing the thrust of the booster engines 10 percent, stretching the Atlas propellant tanks 9 feet, and stretching the Centaur tanks 3 feet.(9)

Notes

1. Adapted from: General Dynamics Convair Division, Atlas Space Launch Vehicle Systems Summary, GDC-BGJ67-001, February 1967;

Air Command and Staff College (Lt Col Curtis D. Cochran, Lt Col Dennis M. Gorman, Maj Joseph D. Dumoulin {editors}), Space Handbook - AU-18, (Air University Press, Maxwell Air Force Base, Alabama, January 1985); and

General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

2. Air Command and Staff College (Lt Col Curtis D. Cochran, Lt Col Dennis M. Gorman, Maj Joseph D. Dumoulin {editors}), Space Handbook - AU-18, (Air University Press, Maxwell Air Force Base, Alabama, January 1985); and

General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

3. General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

4. Adapted from: Air Command and Staff College (Lt Col Curtis D. Cochran, Lt Col Dennis M. Gorman, Maj Joseph D. Dumoulin {editors}), Space Handbook - AU-18, (Air University Press, Maxwell Air Force Base, Alabama, January 1985); and

General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

5. Adapted from: General Dynamics Convair Division, The Atlas Launch Vehicle Family for Spacecraft Contractor Planning, GDC-BGJ67-002, April 1967; and

General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

6. General Dynamics Convair Division, Atlas Space Launch Vehicle Systems Summary, GDC-BGJ67-001, February 1967.

7. Adapted from: General Dynamics Convair Division, Atlas Space Launch Vehicle Systems Summary, GDC-BGJ67-001, February 1967;

General Dynamics Convair Division, The Atlas Launch Vehicle Family for Spacecraft Contractor Planning, GDC-BGJ67-002, April 1967; and

General Dynamics Convair Division, The Atlas Launch Vehicle Family for Spacecraft Contractor Planning, GDC-BGJ67-002, April 1967.

8. General Dynamics Space Systems Division, Atlas Centaur Mission Planners Guide, (April 1983, Revised November 1986), Arlington, Virginia and San Diego, California.

9. US Congress, Office of Technology Assessment, Launch Options for the Future: Buyer's Guide, OTA-ISC-383 (Washington, DC: U.S. Government Printing Office, July 1988), page 46.



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