The Thor-Delta, also known as Delta DM-19 or just Delta was an early 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 ...

used for 12

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...

al launches in the early 1960s. A derivative of the

Thor-Able 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 Vang ...

, it was a member of the

Thor Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding æsir, god associated with lightning, thunder, storms, sacred trees and groves in Germanic paganism and mythology, sacred groves ...

family of rockets, and the first member of the

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also re ...

family. The first stage was a

missile in the DM-19 configuration. The second stage was the

, which had been derived from the earlier

Able Able may refer to: * Able (1920 automobile), a small French cyclecar * Able (rocket stage), an upper stage for Vanguard, Atlas, and Thor rockets * Able (surname) * ABLE account, a savings plan for people with disabilities * Able UK, British ship ...

stage. An

Altair Altair is the brightest star in the constellation of Aquila and the twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinised from α Aquilae and abbreviated Alpha Aql or ...

solid rocket motor A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Arabs, Chinese, Persians ...

was used as a third stage. 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 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 va ...

, remained in service until 2018. The Thor-Delta launched a number of significant payloads, including the first

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

, Echo 1A; the first British satellite,

Ariel 1 Ariel 1 (also known as UK-1 and S-55), 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 Stat ...

; and the first active direct-relay communications satellite,

Telstar 1 Telstar 1 was a communications satellite launched by NASA on July 10, 1962. It was the satellite that allowed the first live broadcast of television images between the United States and Europe. Telstar 1 remained active for only 7 months before i ...

. All 12 launches occurred from

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 ...

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 Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, were metalized balloon satellites acting as passive reflectors of microwave signals. Communication sign ...

into orbit due to a problem with the second stage.

Thor-Delta launches

1963 mystery cloud

On 28 February 1963, a Thor

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pad, launch pads, supported by a missile launch contro ...

carrying a spy satellite into orbit was launched from

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 ...

. The rocket went off course and mission control detonated the rocket at an altitude of before it could reach orbit. The rocket detonation produced a large circular cloud that appeared over the southwestern United States. Due to its mysterious nature, appearing at a very high altitude and being visible for hundreds of miles, the cloud attracted widespread attention and was published by the news media. The cloud was featured on the cover of ''Science Magazine'' in April 1963, ''Weatherwise'' Magazine in May 1963, and had a full page image published in the May issue of ''Life Magazine''. Prof. James MacDonald at the

University of Arizona The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory. T ...

Institute for Atmospheric Physics investigated the phenomena and linked it to the Thor rocket launch after contacting military personnel at Vandenberg Air Force Base. When the launch records were later declassified, the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...

released a memo explaining that the cloud was the result of a military operation.

References

Thor (rocket family) {{rocket-stub

Thor-Delta launches

1963 mystery cloud

See also

References