The Atlas-Agena was an American

expendable launch system An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket sta ...

derived from the

SM-65 Atlas The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dyna ...

missile. It was a member of the

Atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geographic ...

family of rockets, and was launched 109 times between 1960 and 1978.Encyclopedia Astronautica - Atlas
/ref> It was used to launch the first five

Mariner A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship. The profession of the s ...

uncrewed probes to the planets

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...

and

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

, and the

Ranger A Ranger is typically someone in a military/paramilitary or law enforcement role specializing in patrolling a given territory, called “ranging”. The term most often refers to: * Park ranger or forest ranger, a person charged with protecting and ...

and

Lunar Orbiter The Lunar Orbiter program was a series of five uncrewed lunar orbiter missions launched by the United States from 1966 through 1967. Intended to help select Apollo landing sites by mapping the Moon's surface, they provided the first photographs ...

uncrewed probes to the Moon. The upper stage was also used as an uncrewed orbital target vehicle for the

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Northern ...

crewed spacecraft to practice rendezvous and docking. However, the launch vehicle family was originally developed for the Air Force and most of its launches were classified DoD payloads. The Atlas-Agena was a two-and-a-half-stage rocket, with a stage-and-a-half Atlas missile as the first stage, and an

RM-81 Agena The RM-81 Agena was an American rocket upper stage and satellite bus which was developed by Lockheed Corporation initially for the canceled WS-117L reconnaissance satellite program. Following the split-up of WS-117L into SAMOS and Corona for imag ...

second stage. Initially,

Atlas D The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dy ...

missiles, redesignated as the LV-3, were used as the first stage. These were later replaced by the standardized

Atlas SLV-3 The Atlas SLV-3, or SLV-3 Atlas was an American expendable launch system derived from the SM-65 Atlas / SM-65D Atlas missile. It was a member of the Atlas family of rockets. The Atlas SLV-3 was a stage and a half rocket, built as a standardized ...

, and its derivatives, the SLV-3A and B. The final Atlas-Agena launch used an

Atlas E/F The Atlas E/F (or SB-1A) was an American expendable launch system and sounding rocket built using parts of decommissioned SM-65 Atlas missiles. It was a member of the Atlas family of rockets. The first stage was built using parts taken from d ...

. The earliest Agena variant was the Agena A in 1959–60, which did not have restart capability. Most of these were flown on

Thor-Agena Thor-Agena was a series of orbital launch vehicles. The launch vehicles used the Douglas-built Thor first stage and the Lockheed-built Agena second stages. They are thus cousins of the more-famous Thor-Deltas, which founded the Delta rocket ...

boosters for the Discoverer program and only four used Atlases (

Midas Midas (; grc-gre, Μίδας) was the name of a king in Phrygia with whom several myths became associated, as well as two later members of the Phrygian royal house. The most famous King Midas is popularly remembered in Greek mythology for his ...

1, Midas 2,

Samos Samos (, also ; el, Σάμος ) is a Greek island in the eastern Aegean Sea, south of Chios, north of Patmos and the Dodecanese, and off the coast of western Turkey, from which it is separated by the -wide Mycale Strait. It is also a separate ...

1, and Samos 2), two of which failed. Late in 1960, Lockheed introduced the uprated Agena B stage which was restartable and had longer propellant tanks for more burn time. It first flew on the Thor and did not make its maiden voyage on an Atlas for months, when Midas 3 launched on July 12, 1961. Atlas-Agenas were then used for DoD and NASA programs, but proved a reliability nightmare as one failure after another happened. In late 1962, after

Ranger 5 Ranger 5 was a spacecraft of the Ranger program designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to colle ...

suffered another booster malfunction, albeit a minor one that ground controllers were able to work around, NASA convened a review board which undertook a wholesale reevaluation of the Atlas-Agena as a launch vehicle. The board found that quality control and checkout procedures were poor, and that this situation was exacerbated by the several dozen configurations of the booster, as each individual DoD and NASA program necessitated custom modifications to the Atlas and Agena, and the latter also differed in its Atlas and Thor variants. The board recommended improved quality control, better hardware, and also establishing one standardized launch vehicle for all space programs. The end result was the

and Agena D, standardized versions of the Atlas D core and Agena B which would be the same on every launch (at least as far as the Atlas was concerned, Agena Ds often still had customized setups, especially for DoD payloads). The Agena D first flew in July 1963 for DoD launches, but NASA continued using Agena Bs for the remaining Ranger missions. The Atlas SLV-3 meanwhile first flew in August 1964. Dozens of Atlas SLV-3/Agena D boosters were flown over the following years, mostly for the

KH-7 Gambit BYEMAN codenamed GAMBIT, the KH-7 (Air Force Program 206) was a reconnaissance satellite used by the United States from July 1963 to June 1967. Like the older CORONA system, it acquired imagery intelligence by taking photographs and returnin ...

program, also for a few NASA missions. The last Atlas-Agena was flown in 1978 to launch SEASAT, but on a repurposed

Atlas F The SM-65F Atlas, or Atlas-F, was the final operational variant of the Atlas missile, only differing from the Atlas E in the launch facility and guidance package used. It first flew on 8 August 1961, and was deployed as an operational ICBM between ...

missile rather than the SLV-3. Launches were conducted from Launch Complexes 12, 13 and 14 at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

, and Launch Complexes 1 and 2 at

Point Arguello Point Arguello (Spanish: ''Punta Argüello'') is a headland on the Gaviota Coast, in Santa Barbara County, California, near the city of Lompoc. The area was first used by the United States Navy in 1959 for the launch of military and sounding r ...

(now SLC-3 and 4 at

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USS General Harry Taylor (AP-145), USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in K ...

Variants

Destruct system

Some Atlas-Agena variants contained an Inadvertent Separation Destruct System (ISDS) to destroy the Agena in the event that it separated prematurely from the Atlas, a situation that could be caused by a booster hard-over or if the Atlas self-destructed in flight. The ISDS charges were mounted on the adapter section between the two vehicles and would activate if a series of tripwires were broken. During the coasting period between staging, the ISDS charges were disabled. The Atlas's own RSO charges were also wired so that they would destroy both vehicles if activated. Most Agenas also had their own separate RSO charges, although NASA planetary probes omitted them for weight-saving reasons and due to the flight trajectory used, which meant that destruct of the Agena was no longer possible following staging. The Gemini-Agena Target Vehicle had a specially modified Range Safety destruct system designed to fire slugs into the propellant tanks rather than the conventional method of rupturing them externally, since an inadvertent activation of the RSO system in orbit could endanger the Gemini astronauts. The very first Atlas-Agena flight, Midas 1 in February 1960, failed when the unproven ISDS system mistakenly activated at staging, rupturing the Atlas's LOX tank and causing the breakup of the Agena. The ISDS system was redesigned afterwards and this failure mode did not repeat itself.

Production launches

Ranger

The Ranger spacecraft were designed to impact the Moon, returning photographs of the lunar surface until their destruction. The spacecraft was designed in three Blocks, all similar in appearance with a forward antenna and

magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...

, supported by a boom, with more sensors and two solar panels and a dish antenna mounted at the base. The first two Block I spacecraft,

Ranger 1 Ranger 1 was a prototype spacecraft launched as part of the Ranger program of unmanned space missions. Its primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missio ...

and Ranger 2, were launched on August 23 and November 18, 1961, not to the Moon, but in intended high Earth orbits to test the Atlas-Agena and spacecraft capabilities. However, the Agena malfunctioned on both flights and left the probes trapped in a useless low Earth orbit from which they soon decayed. The Block II missions,

Ranger 3 Ranger 3 was a space exploration mission conducted by NASA to study the Moon. The Ranger 3 robotic spacecraft was launched January 26, 1962 as part of the Ranger program. Due to a series of malfunctions, the spacecraft missed the Moon by and ...

Ranger 4 Ranger 4 was a spacecraft of the Ranger program, launched in 1962. It was designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to crashing upon the Moon, to rough-land a seismometer c ...

, and

, were launched away from Earth in January, April, and October 1962, but all three failed due to either malfunctions of the probe or launch vehicle difficulties. Ranger 3 missed the Moon entirely. Ranger 4's solar panels failed to deploy, and the navigation system failed, sending the probe to impact the lunar far side without returning any pictures or data. Ranger 5 suffered an unknown failure which deprived it of power, and it missed the Moon by .

Ranger 6 Ranger 6 was a lunar probe in the NASA Ranger program, a series of robotic spacecraft of the early and mid-1960s to obtain the first close-up images of the Moon's surface. It was launched on January 30, 1964 and was designed to transmit high-reso ...

, launched January 30, 1964, successfully impacted the Moon but its cameras failed to return pictures. The last three Rangers were finally successful:

Ranger 7 Ranger 7 was the first space probe of the United States to successfully transmit close images of the lunar surface back to Earth. It was also the first completely successful flight of the Ranger program. Launched on July 28, 1964, Ranger 7 was d ...

in July 1964,

Ranger 8 Ranger 8 was a lunar probe in the Ranger program, a robotic spacecraft series launched by NASA in the early-to-mid-1960s to obtain the first close-up images of the Moon's surface. These pictures helped select landing sites for Apollo missions an ...

in February 1965, and

Ranger 9 Ranger 9 was a Lunar probe, launched in 1965 by NASA. It was designed to achieve a lunar impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact. The spacecraft carried s ...

in March 1965.

Mariner

The Mariner spacecraft were built by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

Mariner 1 Mariner 1, built to conduct the first American planetary flyby of Venus, was the first spacecraft of NASA's interplanetary Mariner program. Developed by Jet Propulsion Laboratory, and originally planned to be a purpose-built probe launched summ ...

and

Mariner 2 Mariner 2 (Mariner-Venus 1962), an American space probe to Venus, was the first robotic space probe to conduct a successful planetary encounter. The first successful spacecraft in the NASA Mariner program, it was a simplified version of the Bl ...

were twins, launched on July 22 and August 27, 1962, to fly by the planet

. The first two craft used the same

spacecraft bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-d ...

as the Block I Rangers, each weighing and instrumented to perform radiometric temperature measurements of the planet, and to measure interplanetary magnetic fields and particles. Mariner 1's Atlas-Agena malfunctioned and went off course, requiring its destruction approximately 5 minutes after liftoff. Mariner 2 successfully made the 3½-month flight, becoming the first spacecraft to fly by another planet. It carried

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...

and

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

radiometers, and sensors for cosmic dust, solar

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

and high-energy

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

, and

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

Mariner 3 Mariner 3 (together with Mariner 4 known as Mariner-Mars 1964) was one of two identical deep-space probes designed and built by the Jet Propulsion Laboratory (JPL) for NASA's Mariner-Mars 1964 project that were intended to conduct close-up (fl ...

and

Mariner 4 Mariner 4 (together with Mariner 3 known as Mariner-Mars 1964) was the Mariner program, fourth in a series of spacecraft intended for planetary exploration in a flyby mode. It was designed to conduct closeup scientific observations of Mars and ...

used a redesigned spacecraft bus weighing , and were launched on November 5 and November 28, 1964, to fly by the planet

. Mariner 3 failed after a successful launch when its payload shroud failed to open. These Mariners carried cameras, and Mariner 4 successfully returned pictures of Mars as it flew by. The

Mariner 5 Mariner 5 (Mariner Venus 1967) was a spacecraft of the Mariner program that carried a complement of experiments to probe Venus' atmosphere by radio occultation, measure the hydrogen Lyman-alpha (hard ultraviolet) spectrum, and sample the solar ...

was successfully launched to Venus on June 14, 1967, and flew by in October, probing Venus's atmosphere with radio waves, scanning its brightness in

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...

, and sampling solar particles and

fluctuations above the planet.

Gemini

The First Docking in Space - GPN-2000-001344

The Agena rocket stage was used as the passive docking target for the

crewed space program. After docking, the Agena could also be fired by the astronauts to raise the combined Gemini-Agena spacecraft into a higher orbit. The first attempt at such a docking mission was made for the

Gemini 6 Gemini 6A (officially Gemini VI-A) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1965 crewed United States spaceflight in NASA's Gemini program. The mission, flown by Wally Schirra and Thomas P. Stafford, ...

mission on October 25, 1965, but the Agena suffered an engine failure and did not reach orbit. This forced postponement and replanning of the Gemini 6A mission, which performed rendezvous with

Gemini 7 Gemini 7 (officially Gemini VII) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1965 crewed spaceflight in NASA's Gemini program. It was the fourth crewed Gemini flight, the twelfth crewed American spacefli ...

without docking. The GATV was first successfully launched for

Gemini 8 Gemini 8 (officially Gemini VIII) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was the sixth crewed spaceflight in NASA's Gemini program. It was launched on March 16, 1966, and was the 14th crewed American flig ...

on March 16, 1966, permitting the first successful docking in space. GATV-8 was later used as the secondary Agena target for

Gemini 10 Gemini 10 (officially Gemini X) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1966 crewed spaceflight in NASA's Gemini program. It was the 8th crewed Gemini flight, the 16th crewed American flight, and t ...

, which also docked with its own GATV. GATV-9 failed to orbit when the Atlas suffered a control malfunction, forcing a similar reschedule of the

Gemini 9A Gemini 9A (officially Gemini IX-A) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1966 crewed spaceflight in NASA's Gemini program. It was the seventh crewed Gemini flight, the 13th crewed American flight ...

mission using a backup Augmented Target Docking Adapter atop an Atlas, but with no Agena rocket stage. Two more GATVs were successfully launched and used on

Gemini 11 Gemini 11 (officially Gemini XI) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was the ninth crewed spaceflight mission of NASA's Project Gemini, which flew from September 12 to 15, 1966. It was the 17th crewed ...

and

Gemini 12 Gemini 12 (officially Gemini XII) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1966 crewed spaceflight in NASA's Project Gemini. It was the 10th and final crewed Gemini flight ( Gemini 1 and Gemini 2 wer ...

Lunar Orbiter

A series of five Lunar Orbiter spacecraft were launched from August 1966 through August 1967, to help select landing sites for the Apollo lunar landing program by mapping the Moon's surface.Bowker, David E. and J. Kenrick Hughes, Lunar Orbiter Photographic Atlas of the Moo

NASA SP-206 (1971). Each spacecraft weighed and was in diameter, minus the four extended solar panels. All launches were successful, and a total of 99 percent of the surface of the Moon (near and far side) was mapped with resolution as high as 3 ft 3 in (1 meter). Altogether the Orbiters returned 2180 high resolution and 882 medium resolution frames. The spacecraft also carried micrometeroid sensors, which showed the average micro-meteoroid flux near the Moon to be two orders of magnitude greater than in interplanetary space, but slightly less than the near-Earth environment.

OAO

Orbiting Astronomical Observatory The Orbiting Astronomical Observatory (OAO) satellites were a series of four American space observatories launched by NASA between 1966 and 1972, managed by NASA Chief of Astronomy Nancy Grace Roman. These observatories, including the first su ...

was a series of NASA satellites flown between 1966 and 1972 for astronomy studies. The first OAO (launched April 8, 1966) used a one-off Atlas variant, mating an Agena D to the LV-3C variant of the Atlas and encased in a Centaur-type payload shroud. The remaining three launches used actual Atlas-Centaur vehicles.

ATS

Applications Technology Satellite The Applications Technology Satellites (ATS) were a series of experimental satellites launched by NASA, under the supervision of, among others, Wernher von Braun. The program was launched in 1966 to test the feasibility of placing a satellite int ...

was a series of NASA satellites flown in 1967–69 to perform various technology tests. Only the first ATS was launched on an Atlas-Agena, the remainder using Atlas-Centaurs. ATS-1 was a partial failure when the Agena failed to restart, leaving it in LEO.

OGO

Orbiting Geophysical Observatory Orbiting Geophysical Observatory (OGO) Program of NASA refers to the six satellites launched by the United States that were in use from September 1964 to 1972, designed to study the Earth's magnetosphere. The satellites successfully studied th ...

was a series of NASA satellites flown between 1964 and 1969 for magnetosphere studies. These satellites used several different booster types, including Thor-Agenas. Five of them used Atlas-Agenas, and OGO 5 (launched March 4, 1968) was the sole civilian use of the Atlas SLV-3A Agena.

Midas

Missile Defense Alarm System The Missile Defense Alarm System, or MIDAS, was a United States Air Force Air Defense Command system of 12 early-warning satellites that provided limited notice of Soviet intercontinental ballistic missile launches between 1960 and 1966. Original ...

was a series of Air Force satellites flown between 1960 and 1966 for infrared detection of ballistic missile exhaust plumes on Atlas-Agena A, B, and D. There were several failures and overall program performance was poor, but it would give way to the more successful

DSP DSP may refer to: Computing * Digital signal processing, the mathematical manipulation of an information signal * Digital signal processor, a microprocessor designed for digital signal processing * Yamaha DSP-1, a proprietary digital signal ...

satellites.

Samos

was a series of Air Force satellites flown between 1960 and 1962 for photoreconnaissance on Atlas-Agena A and B. There were several failures, including an on-pad explosion of an Atlas, and the program was cancelled at the end of 1962 without ever demonstrating any operational capability.

Gambit

was a series of Air Force satellites flown between 1963 and 1966 for photoreconnaissance on Atlas-Agena D. Although there were a number of mission failures, Gambit overall was highly successful in comparison with the bungled Samos program and it returned high-value area reconnaissance of the USSR and China before giving way to KH-8 Gambit in 1967.

Rhyolite/Canyon

Rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

Canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

was a series of Air Force satellites flown between 1968 and 1978 for SIGNIT intelligence on Atlas SLV-3A Agena. One Canyon mission failed when its Atlas went off course and had to be destroyed. These were the final launches of Atlas-Agena vehicles aside from the one-off Atlas F/Agena used to launch Seasat.

Vela

Vela consisted of two sets of Air Force satellites flown in 1964–65 to monitor Soviet compliance with the Nuclear Test Ban Treaty on Atlas-Agena Ds.

Snapshot

Snapshot Snapshot, snapshots or snap shot may refer to: * Snapshot (photography), a photograph taken without preparation Computing * Snapshot (computer storage), the state of a system at a particular point in time * Snapshot (file format) or SNP, a file ...

was a one-off Air Force test of a nuclear satellite flown in 1965 on an Atlas-Agena D.

References

{{US launch systems Rockets and missiles Atlas (rocket family)