Encyclopedia Astronautica
Atlas Agena A



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Atlas Agena A
Atlas Agena A - Midas 2 - COSPAR 1960 Zeta
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Atlas Agena A
Atlas Agena A - Midas 2 - COSPAR 1960 Zeta
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Atlas D Midas
Credit: © Thomas Kladiva - Thomas Kladiva
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Atlas Agena A
Credit: US Air Force
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Atlas Agena A
Credit: © Mark Wade
American orbital launch vehicle. Atlas D + 1 x Agena A upper stage. Agena originally called 'Hustler', based on engine for cancelled rocket-propelled nuclear warhead pod for B-58 Hustler bomber.

Payload: 800 kg (1,760 lb) to a GTO. Failures: 2. First Fail Date: 1960-02-26. Last Fail Date: 1960-10-11.

Stage Data - Atlas LV-3A / Agena A

  • Stage 0. 1 x Atlas MA-2. Gross Mass: 3,050 kg (6,720 lb). Empty Mass: 3,050 kg (6,720 lb). Thrust (vac): 1,517.422 kN (341,130 lbf). Isp: 282 sec. Burn time: 135 sec. Isp(sl): 248 sec. Diameter: 4.90 m (16.00 ft). Span: 4.90 m (16.00 ft). Length: 0.0000 m ( ft). Propellants: Lox/Kerosene. No Engines: 2. Engine: XLR-89-5. Status: Out of Production.
  • Stage 1. 1 x Atlas Agena LV-3A. Gross Mass: 117,150 kg (258,270 lb). Empty Mass: 2,390 kg (5,260 lb). Thrust (vac): 363.218 kN (81,655 lbf). Isp: 309 sec. Burn time: 330 sec. Isp(sl): 215 sec. Diameter: 3.05 m (10.00 ft). Span: 4.90 m (16.00 ft). Length: 20.27 m (66.50 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: XLR-105-5. Status: Out of Production.
  • Stage 2. 1 x Agena A. Gross Mass: 3,790 kg (8,350 lb). Empty Mass: 885 kg (1,951 lb). Thrust (vac): 68.950 kN (15,501 lbf). Isp: 276 sec. Burn time: 120 sec. Isp(sl): 0.0000 sec. Diameter: 1.52 m (4.98 ft). Span: 1.52 m (4.98 ft). Length: 4.73 m (15.51 ft). Propellants: Nitric acid/UDMH. No Engines: 1. Engine: Bell 8048. Other designations: RM-81. Status: Out of Production.

Historical Essay © Andreas Parsch

Lockheed RM-81 Agena

The Agena space vehicle was used in large numbers during the 1960s and 1970s as upper stage with SLV-2 Thor, SLV-3 Atlas and SLV-5 Titan boosters to launch a variety of military and civilian payloads into orbit. The Agena itself was actually the first general-purpose satellite, and formed the core for many operational satellites and experimental space vehicles. It is included in this missile directory, because the U.S. Air Force allocated the formal missile designator RM-81 to the Agena (see section on RM-81 Designation for details).

In 1955, the U.S. Air Force began its Weapons System 117L program, calling for the development of a strategic satellite system. The initial primary goal of WS-117L was the development an orbital photo-reconnaissance platform, and in October 1956, Lockheed became prime contractor for the system. The core element of WS-117L was a new multipurpose spacecraft with boost and manoeuvering engines, which would act as the second stage of the launch vehicle as well as the carrier vehicle for the reconnaissance system. Lockheed's Agena spacecraft was built around the Bell XLR81 liquid-propellant rocket engine, and was initially known informally as Hustler, because the XLR81 was originally developed for a (later cancelled) rocket-powered weapons pod for the B-58 Hustler bomber. The first launch of a Thor-Agena combination in January 1959 was a failure, but on 28 February that year, Agena scored its first success when a Thor-Agena launcher placed the Discoverer 1 satellite into polar orbit.

Agena A

The first few Agenas, including the vehicle used in the Discoverer 1 launch, used a Bell XLR81-BA-3 rocket engine, but most vehicles of the initial Agena A series used an XLR81-BA-5 (Bell Model 8048). The engine had gimballed nozzles for pitch and yaw control, and could deliver a thrust of 68.9 kN (15500 lb) for up to 120 s.

Launch Vehicle Combination Number of Launches First/Last Launch
Thor (SLV-2) + Agena A 16 21-Jan-1959 / 13-Sep-1960
Atlas (LV-3A) + Agena A 4 26-Feb-1960 / 31-Jan-1961
Total for Agena A 20 21-Jan-1959 / 31-Jan-1961

Launch summary for Agena A

The Thor-Agena A launched the initial reconnaissance satellites of the CORONA (publicly named Discoverer) series (KH-1 system), while the Atlas-Agena A was used for the first two launches of both the Midas (Missile Detection And Surveillance) early-warning system and Samos (Satellite and Missile Observation System) ELINT satellite series.

Agena B

The Agena B had an improved XLR81-BA-7 engine (Bell Model 8081), which could be restarted in space, and was stretched to carry much more propellant, doubling the total burn time to 240 s. Both features greatly increased the versatility of the Agena vehicle. When launched into low orbits, the Agena B had plenty of fuel left for extensive orbital manoeuvers, an important requirement for a reconnaissance platform. Later models of the Agena B used a further improved XLR81-BA-9 (Bell Model 8096) engine, which (among other changes) increased the thrust to 71.1 kN (16000 lb) by using a different type of fuel.

Launch Vehicle Combination Number of Launches First/Last Launch
Thor (SLV-2) + Agena B 44* 26-Oct-1960 / 28-Aug-1964
Thrust-Augmented Thor (SLV-2A/C) + Agena B 3* 29-Jun-1963 / 15-May-1966
Atlas (LV-3A) + Agena B 28 12-Jul-1961 / 21-Mar-1965
Atlas (SLV-3) + Agena B 1 9-Jun-1966
Total for Agena B 76 26-Oct-1960 / 9-Jun-1966

Launch summary for Agena B

* Thor variant counts slightly differ between sources, but Thor-Agena total is not in question

Most of the Thor-Agena B vehicles launched KH-series reconnaissance systems (all KH-2/3 CORONAs, and some satellites of the KH-4 CORONA and KH-5 ARGON series). The remainder included e.g. some ELINT systems of the Samos program. The Atlas-Agena B launched a variety of spacecraft, the major ones being Midas early-warning systems, Samos ELINT systems and Ranger space probes.

Agena C

The designation Agena C was reserved for a proposed enlarged variant, which was to have doubled the capability of the Agena B (most likely by doubling the fuel tank size). However, this version was not built.

Agena D

The majority of Agenas were of the final Agena D variant. This was essentially a "standardized" Agena B, which could accept a variety of payloads (in a conical payload section in the nose) and be fitted to Atlas, Thor or Titan launchers without changes to the basic Agena. The earlier Agena A/B vehicles were tailor-made for their respective payloads and launcher types. The Agena D launched a large number of military and scientific payloads, including e.g. the Gemini-Agena target vehicles used by NASA for space capsule docking experiments in 1966.

Launch Vehicle Combination Number of Launches First/Last Launch
Thor (SLV-2) + Agena D 22* 28-Jun-1962 / 31-May-1967
Thrust-Augmented Thor (SLV-2A/C) + Agena D 60* 28-Feb-1963 / 17-Jan-1968
LTTAT** (SLV-2G/H) + Agena D 22* 9-Aug-1966 / 16-Jul-71
Thorad (SLV-2G/H) + Agena D 21* 18-May-1968 / 25-May-72
Atlas (LV-3A) + Agena D 15 12-Jul-1963 / 20-Jul-1965
Atlas (SLV-3) + Agena D 48 14-Aug-1964 / 5-Nov-1967
Atlas (SLV-3A) + Agena D 12 4-Mar-1968 / 7-Apr-1978
Atlas F + Agena D 1 27-Jun-1978
Titan 3B (SLV-5B) 29 29-Jul-1966 / 23-Oct-1970
Titan 23B 2 21-Jan-1971 / 22-Apr-1971
Titan 33B 3 21-Mar-1971 / 21-Aug-1973
Titan 24B 23 12-Aug-1971 / 21-Aug-1973
Titan 34B 11 10-Mar-1975 / 12-Feb-1987
Total for Agena D 269 28-Jun-1962 / 12-Feb-1987

Launch summary for Agena D

* Thor variant counts slightly differ between sources, but Thor-Agena total is not in question
** LTTAT = Long-Tank Thrust-Augmented Thor (quoted by some sources as identical to Thorad)
Titan 3B was the designation for the Titan 3 + Agena D combination
These derivatives of the Titan 3B are sometimes called 3(23)B, 3(33B), 3(24)B and 3(34)B, respectively.

The majority of Agena D missions on Thor-type boosters launched KH-series reconnaissance systems, mostly CORONA (KH-4/4A/4B), but also ARGON (KH-5) and LANYARD (KH-6). Most of the initial Atlas-Agena D vehicles (LV-3A/SLV-3) launched GAMBIT satellites (KH-7 reconnaissance system) into orbit, but payloads also included the Mariner series of interplanetary probes and the GATV (Gemini-Agena Target Vehicle). The SLV-3A/Agena D was used to launch the CANYON and RHYOLITE/AQUACADE series of ELINT/SIGINT satellites into geostationary orbits.

The Titan 3B/23B/24B series launched GAMBIT (KH-8 reconnaissance system) satellites, while the payloads of the larger Titan 33B/34B boosters consisted of JUMPSEAT SIGINT and SDS communications satellites.

A total of 365 Agena vehicles of all types were launched into space by the U.S. Air Force and NASA between January 1959 and 12 February 1987, when the last Agena D was launched with a USAF payload (SDS communications satellite #7) as upper stage of a Titan 34B booster.

RM-81 Designation

In 1958 (or early 1959), the U.S. Air Force allocated the formal "Research Missile" designation RM-81 to the Agena space vehicle. The reasons for this remain unclear, but the USAF possibly needed to assign a designator for formal purposes and there was no better alternative at that time. USAF serial number listings show a total order of 341 Agenas, designated as XRM-81, RM-81, SRM-81 and SRM-81A. Because I cannot connect these four designators in any way to the documented basic Agena variants (Agena A/B/D), I don't know what the significance of the different RM-81 designations is. The table below is a detailed listing of allocated Agena serial number blocks, sorted by type designation:

    Serial Range Designation Total Number Ordered
    59-2544/2557
    60-606/615
    60-5454/5463
    60-6594/6630
    60-6914/6922
    62-12585
    XRM-81 81
    60-3710/3719 RM-81 10
    63-7368/7406
    63-12759/12764
    65-10657/10685
    66-4390/4432
    66-9249/9262
    67-14544/14579
    SRM-81 167
    61-4530/4536
    62-3876/3878
    62-4614/4625
    62-12202/12213
    62-12289/12291
    63-13040/13085
    SRM-81A 83

Notes:
1. The Agena did not receive a new designation in June 1963, when the joint DOD missile designation system was introduced, because spacecraft were not originally part of the new system.
2. One would expect that SRM-81A designated a newer version than SRM-81 (before 1962, an "A" suffix designated the second version), but the latest blocks are all attributed to plain SRM-81. However, after June 1963 the Agena's designation was no longer covered by any official regulation, so it's possible that the general SRM-81 designator was not meant to designate any specific variant, but was only retained in the serial number list for informal purposes.
3. The 341 serials do not account for the full number of Agenas built (at least 365).

Specifications

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate! Because exact numbers for each Agena depend on payload configuration, the data are to be regarded as "typical" values.

Data for Agena A, Agena B, Agena D:

  Agena A Agena B/D
Length 5.94 m (19.5 ft) 7.56 m (24.8 ft)
Diameter 1.52 m (5 ft)
Weight 3850 kg (8500 lb)
Fuel: 2945 kg (6500 lb)
7160 kg (15800 lb)
Fuel: 6115 kg (13500 lb)
Propulsion Bell XLR81-BA-5 liquid-fuel rocket;
68.9 kN (15500 lb) for 120 s
Bell XLR81-BA-9 liquid-fuel rocket;
71.1 kN (16000 lb) for 240 s
Main Sources

[1] Jos Heyman: "World Spacecraft Digest 1957-2002", Tiros Space Information, 2003
[2] Jos Heyman: "Spacecraft Tables 1957-2002", Tiros Space Information, 2003
[3] Ren J. Francillon: "Lockheed Aircraft since 1913", Putnam, 1987
[4] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
[5] Mark Wade: Encyclopedia Astronautica
[6] Gunter Krebs: Gunter's Space Page
[7] USAF Aircraft Serial Number Records (data provided by Jos Heyman)


AKA: Atlas-Hustler; LV-3A.
Gross mass: 123,990 kg (273,350 lb).
Payload: 800 kg (1,760 lb).
Height: 30.00 m (98.00 ft).
Diameter: 3.05 m (10.00 ft).
Thrust: 1,587.19 kN (356,815 lbf).
Apogee: 600 km (370 mi).
First Launch: 1960.02.26.
Last Launch: 1961.01.31.
Number: 4 .

More... - Chronology...


Associated Countries
Associated Spacecraft
  • Aeronutronics Project 7969 American manned spacecraft. Study 1958. Aeronutronics' proposal for the Air Force initial manned space project was a cone-shaped vehicle 2.1 m in diameter with a spherical tip of 30 cm radius. It does not seem to have been seriously considered. More...
  • Convair Project 7969 American manned spacecraft. Study 1958. Convair's proposal for the Air Force initial manned space project involved a large-scale manned space station. When pressed, they indicated that a minimum vehicle - a 450 kg, 1. More...
  • Lockheed Project 7969 American manned spacecraft. Study 1958. Lockheed's proposal for the Air Force initial manned space project was a 20 degree semiapex angle cone with a hemispherical tip of 30 cm radius. The pilot was in a sitting position facing rearward. More...
  • Midas American military early warning satellite. 18 launches, 1960.02.26 (Midas 1) to 1966.10.05 (Midas 12). Part of a then-secret USAF program known as WS-117L, the MIDAS (Missile Defense Alarm System) program began in November 1958. More...
  • Samos American military surveillance satellite. 17 launches, 1960.10.11 (Samos 1) to 1962.11.11 (Samos 11). First generation photo surveillance; return of camera and film by capsule; program still partially classified, evidently due to embarrassment. More...

Associated Engines
  • Bell 8048 Bell Nitric acid/UDMH rocket engine. 68.9 kN. Out of production. Isp=276s. Used on Agena A, derived from Rascal engine. Regeneratively cooled; used drilled holes to create the same effect as more costly stacked spaghetti rubes. First flight 1959. More...
  • XLR105-5 Rocketdyne Lox/Kerosene rocket engine. 363.2 kN. Atlas D. Atlas Sustainer. Gas generator, pump-fed. Shared turbopumps for booster engines. Isp=309s. First flight 1958. More...
  • XLR89-5 Rocketdyne Lox/Kerosene rocket engine. 758.7 kN. Atlas D. Designed for booster applications. Gas generator, pump-fed. Shared turbopumps for booster engines. Isp=282s. First flight 1958. More...

See also
  • Atlas The Atlas rocket, originally developed as America's first ICBM, was the basis for most early American space exploration and was that country's most successful medium-lift commercial launch vehicle. It launched America's first astronaut into orbit; the first generations of spy satellites; the first lunar orbiters and landers; the first probes to Venus, Mars, Mercury, Jupiter, and Saturn; and was America's most successful commercial launcher of communications satellites. Its innovative stage-and-a-half and 'balloon tank' design provided the best dry-mass fraction of any launch vehicle ever built. It was retired in 2004 after 576 launches in a 47-year career. More...

Associated Manufacturers and Agencies
  • Convair American manufacturer of rockets, spacecraft, and rocket engines. Convair, USA. More...

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Vandenberg Vandenberg Air Force Base is located on the Central Coast of California about 240 km northwest of Los Angeles. It is used for launches of unmanned government and commercial satellites into polar orbit and intercontinental ballistic missile test launches toward the Kwajalein Atoll. More...
  • Cape Canaveral LC14 Atlas launch complex. The complex was built for the Atlas ballistic missile program. Launch sites 11 to 14 were accepted between August 1957 and mid-April 1958. After its final Atlas missile launch, Complex 14 was converted into an Atlas /Agena launch complex, and later turned over to NASA. Complex 14 supported 32 Atlas and Atlas/Agena missions, including four manned Mercury missions and seven unmanned Gemini target vehicle launches. Complexes 11, 12 and 14 were deactivated in 1967. Complex 14 and the gantry on Complex 13 were declared national historic landmarks in April 1984. More...
  • Vandenberg SLC3W Delta, Atlas launch complex. First designated LC1-1 and used to launch Atlas Agena B with Samos payloads. After Samos cancellation, rebuilt in 1963 to support launch of KH-4 Corona spysats atop Thor-Agena. Refurbished in 1973 to accomodate surplus Atlas ICBM's in space launch role. More...

Associated Stages
  • Agena A Nitric acid/UDMH propellant rocket stage. Loaded/empty mass 3,790/885 kg. Thrust 68.95 kN. Vacuum specific impulse 276 seconds. The Agena space vehicle was used in large numbers during the 1960s and 1970s as upper stage with SLV-2 Thor, SLV-3 Atlas and SLV-5 Titan boosters to launch a variety of military and civilian payloads into orbit. The Agena itself was actually the first general-purpose satellite, and formed the core for many operational satellites and experimental space vehicles. More...
  • Atlas MA-2 Lox/Kerosene propellant rocket stage. Loaded/empty mass 3,050/3,050 kg. Thrust 1,517.42 kN. Vacuum specific impulse 282 seconds. More...
  • Atlas Agena LV-3A Lox/Kerosene propellant rocket stage. Loaded/empty mass 117,150/2,390 kg. Thrust 363.22 kN. Vacuum specific impulse 309 seconds. More...

Atlas Agena A Chronology


1960 February 26 - . 17:25 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC14. LV Family: Atlas. Launch Vehicle: Atlas Agena A. LV Configuration: Atlas Agena A 29D / Agena A 1008. FAILURE: Second stage failed to separate.. Failed Stage: 2.
  • Midas 1 - . Payload: Midas / Agena TV 1008. Mass: 2,025 kg (4,464 lb). Nation: USA. Agency: USAF. Class: Military. Type: Early warning satellite. Spacecraft: Midas. Decay Date: 1960-02-26 . COSPAR: F600226A. Summary: Missile Defense Alarm System..

1960 May 24 - . 17:36 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC14. LV Family: Atlas. Launch Vehicle: Atlas Agena A. LV Configuration: Atlas Agena A 45D / Agena A 1007.
  • Midas 2 - . Payload: Midas / Agena TV 1007. Mass: 2,300 kg (5,000 lb). Nation: USA. Agency: USAF. Class: Military. Type: Early warning satellite. Spacecraft: Midas. Decay Date: 1974-02-07 . USAF Sat Cat: 43 . COSPAR: 1960-Zeta-1. Apogee: 494 km (306 mi). Perigee: 473 km (293 mi). Inclination: 33.0000 deg. Period: 94.30 min. Summary: Missile Defense Alarm System. Test launch with W-17 sensor..

1960 October 11 - . 20:33 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC3W. LV Family: Atlas. Launch Vehicle: Atlas Agena A. LV Configuration: Atlas Agena A 57D / Agena A 2101. FAILURE: Second stage failure.. Failed Stage: 2.
  • Samos 1 - . Payload: Samos E-1 no. 1. Mass: 1,845 kg (4,067 lb). Nation: USA. Agency: USAF. Class: Surveillance. Type: Military surveillance satellite. Spacecraft: Samos. Decay Date: 1960-10-11 . COSPAR: F601011A. Summary: First generation photo surveillance; radio relay of images; Satellite and Missile Observation Satellite..

1961 January 31 - . 20:21 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC3W. LV Family: Atlas. Launch Vehicle: Atlas Agena A. LV Configuration: Atlas Agena A 70D / Agena A 2102.
  • Samos 2 - . Payload: Samos E-1 no. 2. Mass: 1,900 kg (4,100 lb). Nation: USA. Agency: USAF. Class: Surveillance. Type: Military surveillance satellite. Spacecraft: Samos. Decay Date: 1973-10-21 . USAF Sat Cat: 70 . COSPAR: 1961-Alpha-1. Apogee: 557 km (346 mi). Perigee: 474 km (294 mi). Inclination: 97.4000 deg. Period: 95.00 min. Summary: First generation photo surveillance; radio relay of images; micrometeoroid impact data. Poor results..

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