Thor was a US space launch vehicle derived from the PGM-17 Thor intermediate-range ballistic missile. The Thor rocket was the first member of the Delta rocket family of space launch vehicles. The last launch of a direct derivative of the Thor missile occurred in 2018 as the first stage of the final Delta II.
Thor was first used as a launch vehicle during the testing program of the warhead reentry vehicle for the Atlas missile. [1] For these three tests a Thor core stage was topped by the Able second stage. Able used the Aerojet AJ-10-40 engine from the Vanguard second stage. The first such launch, 116, was lost on 23 April 1958 due to a turbopump failure in the main engine. The recovery of the reentry vehicles on the succeeding two attempts were not successful. Three mice, one on each vehicle, died in these tests.[ citation needed ]
The Able stage from the Atlas reentry vehicle tests was upgraded to become the Able I with a third stage consisting of an unguided Altair X-248 solid-fuel rocket motor. A Thor Able I was used in an attempt to place the 84 lb (38 kg) Pioneer 0 spacecraft into lunar orbit where it would take pictures of the lunar surface with a TV camera. The mission ended prematurely at 73.6 seconds after launch on 17 August 1958 due to a turbopump failure.
On 7 August 1959, a Thor-Able was used to successfully launch Explorer 6, the first satellite to transmit pictures of Earth taken from orbit.
Ablestar was a liquid-propellant rocket stage burning hypergolic propellants fed from gas-pressurized propellant tanks. It was used as the upper stage, and provided improved performance.[ citation needed ] On 13 April 1960, a Thor-Ablestar launched Transit 1B, the first experimental satellite of what eventually became the Global Navigation Satellite System. [2] On 22 June 1960, a Thor-Ablestar launched the first Galactic Radiation and Background (GRAB) electronic intelligence (ELINT) satellite for the United States Navy. These now-declassified satellites operated under a cover story of providing solar radiation data and included an electronics package to detect Soviet air defense radar signals. [3] GRAB-1 was the world's first successful reconnaissance satellite, preceding the first Corona mission to return film (Discoverer 14 on August 18) by almost two months. On 29 June 1961, the Ablestar stage used to launch Transit 4A, which became the first object to unintentionally explode in space, creating at least 294 trackable pieces of space debris. [4]
The Delta second stage was derived from the Able second stage. Members of the Delta rocket family derived from the Thor-Delta continue to launch satellites and space probes.
By 1969, the Thor core was being used regularly both in Delta vehicles and in the USAF Standard Space Launch Vehicle (SLV-2), with thrust augmentation and a variety of upper stages.
Together with the Agena upper stage, Thor was the booster of the Thor-Agena vehicle used to launch the early Corona (also known as "Keyhole" and "Discoverer") satellites from Vandenberg AFB. [5] These were the first photographic spy satellites, used for photographic surveillance of the Soviet Union, China and other areas. Thor-Agenas were used as launch vehicles for Corona satellites from June 1959 through May 1963.
The Thrust Augmented Thor (TAT) was developed to handle the growing satellites of the Corona program. It added three Castor solid-fuel rocket strapon boosters—each providing 53,000 lbf (236 kN) thrust—to the standard Thor core stage. The boosters were lit on the ground and jettisoned after burnout.
The Thrust-Augmented Long Tank Thor/Agena incorporated modifications allowing 49,000 lb (22,000 kg) more propellant and was capable of sending payloads ranging from 1400 to about 2800 pounds into 100-nautical-mile (190 km) polar circular orbits. [6]
The Thorad-Agena (pictured) was developed from Thor. It used a Long Tank Thor to launch an Agena-D upper stage.
Pioneer 1 was an American space probe, the first under the auspices of NASA, which was launched by a Thor-Able rocket on 11 October 1958. It was intended to orbit the Moon and make scientific measurements, but due to a guidance error failed to achieve lunar orbit and was ultimately destroyed upon reentering Earth's atmosphere. The flight, which lasted 43 hours and reached an apogee of 113,800 km, was the second and most successful of the three Thor-Able space probes.
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 image intelligence, and MIDAS for early warning, the Agena was later used as an upper stage, and an integrated component, for several programs, including Corona reconnaissance satellites and the Agena Target Vehicle used to demonstrate rendezvous and docking during Project Gemini. It was used as an upper stage on the Atlas, Thor, Thorad and Titan IIIB rockets, and considered for others including the Space Shuttle and Atlas V. A total of 365 Agena rockets were launched between February 28, 1959 and February 1987. Only 33 Agenas carried NASA payloads and the vast majority were for DoD programs.
The PGM-17A Thor was the first operational ballistic missile of the United States Air Force (USAF). Named after the Norse god of thunder, it was deployed in the United Kingdom between 1959 and September 1963 as an intermediate-range ballistic missile (IRBM) with thermonuclear warheads. Thor was 65 feet (20 m) in height and 8 feet (2.4 m) in diameter. It was later augmented in the U.S. IRBM arsenal by the Jupiter.
Delta is an American versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. Japan also launched license-built derivatives from 1975 to 1992. More than 300 Delta rockets have been launched with a 95% success rate. Only the Delta IV Heavy rocket remains in use as of November 2020. Delta rockets have stopped being manufactured in favor of Vulcan.
The SAMOS or SAMOS-E program was a relatively short-lived series of reconnaissance satellites for the United States in the early 1960s, also used as a cover for the initial development of the KH-7 GAMBIT system. Reconnaissance was performed with film cameras and television surveillance from polar low Earth orbits with film canister returns and transmittals over the United States. SAMOS was first launched in 1960 from Vandenberg Air Force Base.
The Thor-Able was an American expendable launch system and sounding rocket used for a series of re-entry vehicle tests and satellite launches between 1958 and 1960. It was a two-stage rocket, consisting of a Thor IRBM as a first stage and a Vanguard-derived Able second stage. On some flights, an Altair solid rocket motor was added as a third stage. It was a member of the Thor family and an early predecessor of the Delta.
The Scout family of rockets were American launch vehicles designed to place small satellites into orbit around the Earth. The Scout multistage rocket was the first orbital launch vehicle to be entirely composed of solid fuel stages. It was also the only vehicle of that type until the successful launch of the Japanese Lambda 4S in 1970.
Space Launch Complex 3 (SLC-3) is a launch site at Vandenberg Space Force Base that consists of two separate launch pads. SLC-3E (East) is currently used by the Atlas V launch vehicle, while SLC-3W (West) has been demolished.
The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was launched 109 times between 1960 and 1978. It was used to launch the first five Mariner uncrewed probes to the planets Venus and Mars, and the Ranger and Lunar Orbiter uncrewed probes to the Moon. The upper stage was also used as an uncrewed orbital target vehicle for the Gemini 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 Castor family of solid-fuel rocket stages and boosters built by Thiokol and used on a variety of launch vehicles. They were initially developed as the second-stage motor of the Scout rocket. The design was based on the MGM-29 Sergeant, a surface-to-surface missile developed for the United States Army at the Jet Propulsion Laboratory.
Atlas is a family of US missiles and space launch vehicles that originated with the SM-65 Atlas. The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the Convair Division of General Dynamics. Atlas was a liquid propellant rocket burning RP-1 fuel with liquid oxygen in three engines configured in an unusual "stage-and-a-half" or "parallel staging" design: two outboard booster engines were jettisoned along with supporting structures during ascent, while the center sustainer engine, propellant tanks and other structural elements remained connected through propellant depletion and engine shutdown.
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 family. The first attempted launch of a Thor-Agena was in January 1959. The first successful launch was on 28 February 1959, launching Discoverer 1. It was the first two-stage launch vehicle to place a satellite into orbit.
Discoverer 1 was the first of a series of satellites which were part of the CORONA reconnaissance satellite program. It was launched on a Thor-Agena A rocket on 28 February 1959 at 21:49:16 GMT from Vandenberg Air Force Base in California. It was a prototype of the KH-1 satellite, but did not contain either a camera or a film capsule. It was the first satellite launched toward the South Pole in an attempt to achieved a polar orbit, but was unsuccessful. A CIA report, later declassified, concluded that "Today, most people believe the Discoverer 1 landed somewhere near the South Pole".
The Thorad-Agena was an American expendable launch system, derived from the Thor and Delta rockets. The first stage of the rocket was a stretched Thor variant named "Long Tank Thrust Augmented Thor". The Long Tank Thor first stage was later adopted by NASA's Delta program for its "Thrust Augmented Improved Delta", which first flew in 1968. The second stage was the Agena-D, which had already been used in conjunction with the standard configuration Thor, as the Thor-Agena. Three Castor rockets would be used as boosters. Most launches carried Corona (KeyHole) reconnaissance satellites, particularly spacecraft of the KH-4 series, however some scientific and technology development satellites were also flown, mostly towards the end of the program.
Juno II was an American space launch vehicle used during the late 1950s and early 1960s. It was derived from the Jupiter missile, which was used as the first stage.
The Thor-Ablestar, or Thor-Able-Star, also known as Thor-Epsilon was an early American expendable launch system consisting of a PGM-17 Thor missile, with an Ablestar upper stage. It was a member of the Thor family of rockets, and was derived from the Thor-Able.
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 Able rocket stage was a rocket stage manufactured in the United States by Aerojet as the second of three stages of the Vanguard rocket used in the Vanguard project from 1957 to 1959. The rocket engine used nitric acid and UDMH as rocket propellants. The Able rocket stage was discontinued in 1960. The improved Ablestar version was used as the upper stage of the Thor-Ablestar two stage launcher. The Ablestar second stage was an enlarged version of the Able rocket stage, which gave the Thor-Ablestar a greater payload capacity compared to the earlier Thor-Able. It also incorporated restart capabilities, allowing a multiple-burn trajectory to be flown, further increasing payload, or allowing the rocket to reach different orbits. It was the first rocket to be developed with such a capability and development of the stage took a mere eight months.
Discoverer 8, also known as Corona 9005, was an American optical reconnaissance satellite launched on 20 November 1959 at 19:25:24 GMT, the fifth of ten operational flights of the Corona KH-1 spy satellite series. Overburn by the carrier rocket placed the satellite in a higher apogee, more eccentric orbit than planned, the camera failed to operate, and the film return capsule was lost on reentry after separation from the main satellite on 21 November.
Discoverer 15, also known as Corona 9010, was a spy satellite used in the Corona program managed by Advanced Research Projects Agency (ARPA) of the Department of Defense and the United States Air Force. Launched on 13 September 1960, the satellite took reconnaissance photos of the Soviet Union. However, its recoverable film capsule was lost in the Pacific Ocean after reentry outside the recovery zone on 15 September.
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