Thor-Delta prior to the launch of Explorer 10
|Function||Expendable launch system|
|Country of origin||United States|
|Launch sites||Cape Canaveral LC-17|
The Thor-Delta, also known as Delta DM-19 or just Delta was an early American expendable launch system used for 12 orbital launches in the early 1960s. A derivative of the Thor-Able, it was a member of the Thor family of rockets, and the first member of the Delta family.
An expendable launch system 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 stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. Most satellites and human spacecraft are currently launched on ELVs. ELVs are simpler in design than reusable launch systems and therefore may have a lower production cost. Furthermore, an ELV can use its entire fuel supply to accelerate its payload, offering greater fuel efficiency. ELVs are proven technology in wide-use for many decades. ELVs are usable only once, and therefore have a significantly higher per-launch cost than reusable vehicles. New reusable launch systems under development by private companies such as SpaceX and Blue Origin have the potential to obsolete many existing ELVs due to the lower per-launch costs of reusable rockets.
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the central mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion.
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 first stage was a Thor missile in the DM-19 configuration. The second stage was the Delta, which had been derived from the earlier Able stage. An Altair solid rocket motor was used as a third stage.
The PGM-17A Thor was the first operational ballistic missile of the U.S. 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.
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.
The Altair was a solid-fuel rocket with a fiberglass casing, initially developed for use as the third stage of Vanguard rockets. It was manufactured by Allegany Ballistics Laboratory (ABL) as the X-248. It was also sometimes called the Burner 1.
The basic design of the original Vanguard upper stages, featuring a pressure-fed nitric acid/UDMH, regeneratively cooled engine, was kept in place, but with an improved AJ10-118 engine. More significantly, the Delta stage featured cold gas attitude control jets allowing it to be stabilized in orbit for restart and more precise burns.
The Thor-Delta was the first rocket to use the combination of a Thor missile and a Delta upper stage. This configuration was reused for many later rockets, and a derivative, the Delta II, remained in service until 2018.
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 variants. The rocket flew its final mission ICESat-2 on 15 September 2018, earning the launch vehicle a streak of 100 successful missions in a row, with the last failure being GPS IIR-1 in 1997.
The Thor-Delta launched a number of significant payloads, including the first communications satellite, Echo 1A; the first British satellite, Ariel 1; and the first active direct-relay communications satellite, Telstar 1. All 12 launches occurred from Cape Canaveral Air Force Station Launch Complex 17. The launch of Telstar 1 used pad B, while all other launches were from pad A. All launches were successful except the maiden flight, which failed to place Echo 1 into orbit due a problem with the second stage.
A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are 2,134 communications satellites in Earth's orbit, used by both private and government organizations. Many are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.
Ariel 1, was the first British satellite, and the first satellite in the Ariel programme. Its launch in 1962 made the United Kingdom the third country to operate a satellite, after the Soviet Union and the United States. It was constructed in both the UK and the United States by NASA Goddard Space Flight Center and SERC, under an agreement reached as the result of political discussions in 1959 and 1960.
Telstar is the name of various communications satellites. The first two Telstar satellites were experimental and nearly identical. Telstar 1 launched on top of a Thor-Delta rocket on July 10, 1962. It successfully relayed through space the first television pictures, telephone calls, and telegraph images, and provided the first live transatlantic television feed. Telstar 2 launched May 7, 1963. Telstar 1 and 2—though no longer functional—still orbit the Earth.
|1||May 13, 1960||Echo 1||CCAFS LC 17A||Failure||Launch at 9:16 p.m. GMT. Good first stage. Second-stage attitude control system failure. Vehicle destroyed.|
|2||August 12, 1960||Echo 1A||CCAFS LC 17A||Success||Payload placed into 1,035 miles (1,666 km), 47 degree inclination orbit.|
|3||November 23, 1960||TIROS-2||CCAFS LC 17A||Success|
|4||March 25, 1961||Explorer-10||CCAFS LC 17A||Success||78 pounds (35 kg) payload placed into elliptical 138,000 miles (222,000 km) orbit.|
|5||July 12, 1961||TIROS-3||CCAFS LC 17A||Success|
|6||August 16, 1961||Explorer-12||CCAFS LC 17A||Success||Energetic Particle Explorers. EPE-A. Highly elliptical orbit.|
|7||February 8, 1962||TIROS-4||CCAFS LC 17A||Success|
|8||March 7, 1962||OSO-1||CCAFS LC 17A||Success||Orbiting Solar Observatory. 345 miles (555 km), 33 degree orbit.|
|9||April 26, 1962||Ariel 1||CCAFS LC 17A||Success||Ariel 1 was later seriously damaged by the Starfish Prime nuclear test.|
|10||June 19, 1962||TIROS-5||CCAFS LC 17A||Success|
|11||July 10, 1962||Telstar 1||CCAFS LC 17B||Success||Telstar 1 was later damaged by the Starfish Prime high altitude nuclear event.|
|12||September 18, 1962||TIROS-6||CCAFS LC 17A||Success|
Delta (rocket family)
Delta is an American versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. More than 300 Delta rockets have been launched with a 95% success rate. Only the Delta IV Heavy rocket remains in use as of August 22, 2019. Delta rockets are currently manufactured and launched by the United Launch Alliance.
The Delta G, or Thor-Delta G was an American expendable launch system used to launch two biological research satellites in 1966 and 1967. It was a member of the Delta family of rockets.
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.
The R-7 family of rockets is a series of rockets, derived from the Soviet R-7 Semyorka, the world's first ICBM. More R-7 rockets have been launched than any other family of large rockets.
The Delta E, or Thor-Delta E was an American expendable launch system used for twenty-three orbital launches between 1965 and 1971. It was a member of the Delta family of rockets.
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 N-II or N-2 was a derivative of the American Delta rocket, produced under licence in Japan. It replaced the N-I-rocket in Japanese use. It used a Thor-ELT first stage, a Delta-F second stage, nine Castor SRMs, and on most flights either a Star-37E or Burner-2 upper stage, identical to the US Delta 0100 series configurations. Eight were launched between 1981 and 1987, before it was replaced by the H-I, which featured Japanese-produced upper stages. All eight launches were successful.
The Thor DSV-2U or Thor LV-2F Star-37XE Star-37S-ISS was an American expendable launch system used to launch five DMSP weather satellites between 1976 and 1980. It was a member of the Thor family of rockets, and a derivative of the Thor DSV-2.
The Delta A, or Thor-Delta A was an American expendable launch system used to launch two Explorer spacecraft in October 1962. A derivative of the Thor-Delta, it was a member of the Delta family of rockets.
The Delta B, or Thor-Delta B was an American expendable launch system used for nine orbital launches between 1962 and 1964. A derivative of the Thor-Delta, it was a member of the Delta family of rockets.
The Delta C, or Thor-Delta C was an American expendable launch system used for thirteen orbital launches between 1963 and 1969. It was a member of the Delta family of rockets.
The Delta D, Thrust Augmented Delta or Thor-Delta D was an American expendable launch system used to launch two communications satellites in 1964 and 1965. It was derived from the Delta C, and was a member of the Delta family of rockets.
The Delta L, Thor-Delta L, or Thrust-Augmented Long Tank Thor-Delta was a US expendable launch system used to launch the Pioneer E and TETR satellites in 1969 (failed) and HEOS satellite in 1972. It was a member of the Delta family of rockets.
The Delta M or Thor-Delta M was an American expendable launch system used for thirteen orbital launches between 1968 and 1971. It was a member of the Delta family of rockets.
The Delta N or Thor-Delta N was an American expendable launch system used for nine orbital launches between 1968 and 1972. It was a member of the Delta family of rockets, and the last Delta to be given an alphabetical designation - subsequent rockets were designated using a four digit numerical code.
The Delta 1000 series was an American expendable launch system which was used to conduct eight orbital launches between 1972 and 1975. It was a member of the Delta family of rockets. Several variants existed, differentiated by a four digit numerical code.
The Delta 2000 series was an American expendable launch system which was used to conduct forty-four orbital launches between 1974 and 1981. It was a member of the Delta family of rockets. Several variants existed, which were differentiated by a four digit numerical code.
The Delta 1000, 2000 and 3000 series used surplus NASA Apollo program rockets engines for its first and second stages.
The Delta 3000 series was an American expendable launch system which was used to conduct 38 orbital launches between 1975 and 1989. It was a member of the Delta family of rockets. Several variants existed, which were differentiated by a four digit numerical code.
The Proton-K, also designated Proton 8K82K after its GRAU index, 8K82K, was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81 and 200 at the Baikonur Cosmodrome in Kazakhstan.
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