The Halley Armada is the name of a series of space probes, five of which were successful, sent to examine

Halley's Comet Halley's Comet is the only known List of periodic comets, short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after ...

during its 1986 sojourn through the inner Solar System, connected with apparition "1P/1982 U1". The armada included one probe from the

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

, two probes that were joint projects between the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and two probes from the

Institute of Space and Astronautical Science , or ISAS, is a Japanese national research organization of astrophysics using rockets, astronomical satellites and interplanetary probes which played a major role in Japan's space development. Established as part of the University of Tokyo ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. Notably,

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

did not contribute a probe to the Halley Armada.

Main space probes

Probes involved (in order of closest approach)

Giotto Giotto di Bondone (; – January 8, 1337), known mononymously as Giotto, was an List of Italian painters, Italian painter and architect from Florence during the Late Middle Ages. He worked during the International Gothic, Gothic and Italian Ren ...

(596 km), the first space probe to get close-up color images of the nucleus of a comet. (ESA) * Vega 2 (8,030 km), which dropped a balloon probe and lander on

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

before going on to Halley. (USSR/France Intercosmos) * Vega 1 (8,889 km), which dropped a balloon probe and lander on Venus before going on to Halley. (USSR/France Intercosmos) * Suisei (151,000 km), also known as PLANET-A. Data from Sakigake was used to improve upon Suisei for its dedicated mission to study Halley. (ISAS) *

Sakigake , known before launch as MS-T5, was Japan's first interplanetary spaceflight, interplanetary spacecraft and the first deep space probe to be launched by any country other than the US or the Soviet Union. It aimed to demonstrate the performan ...

(6.99 million km), Japan's first probe to leave the Earth system, mainly a test of interplanetary mission technology. (ISAS) Without the measurements from the other space probes, Giotto's closest distance would have been 4,000 km instead of the 596 km achieved.

Chronological order of each of the probes' flybys (date of closest approach)

* Vega 1 (March 6, 1986) * Suisei (March 8, 1986) * Vega 2 (March 9, 1986) *

(March 11, 1986) * Giotto (March 14, 1986)

Other missions

Other space probes had their instruments examining Halley's Comet: *

Pioneer 7 Pioneer commonly refers to a person who is among the first at something that is new to a community. A pioneer as a settler is among the first settling at a place that is new to the settler community. A historic example are American pioneers, perso ...

was launched on August 17, 1966. It was put into heliocentric orbit with a mean distance of 1.1 AU to study the solar magnetic field, the solar wind, and cosmic rays at widely separated points in solar orbit. On 20 March 1986, the spacecraft flew within 12.3 million kilometers of Halley's Comet and monitored the interaction between the cometary hydrogen tail and the solar wind. *

Pioneer Venus Orbiter The ''Pioneer Venus Orbiter'', also known as ''Pioneer Venus 1'' or ''Pioneer 12'', was a mission to Venus conducted by NASA as part of the Pioneer Venus project. Launched in May 1978 atop an Atlas-Centaur rocket, the spacecraft was inserted into ...

in orbit of Venus, was positioned perfectly to take measurements of Halley's Comet during its

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

February 9, 1986. Its UV-spectrometer observed the water loss when Halley's Comet was difficult to observe from the Earth. *

International Cometary Explorer The International Cometary Explorer (ICE) spacecraft, designed and launched as the International Sun-Earth Explorer-3 (ISEE-3) satellite, was launched on 12 August 1978 into a heliocentric orbit. It was one of three spacecraft, along with the m ...

, which was repurposed as a cometary probe in 1982 and visited Comet Giacobini-Zinner in 1985, transited between the Sun and Halley's Comet in late March 1986 and took measurements.

Failed and cancelled missions

The Space Shuttle ''Challenger'', on its launch on January 28, 1986, was carrying SPARTAN-203 with the mission to make observations of Halley's Comet. STS-51L failed to reach orbit, resulting in the total loss of crew and vehicle. That launch failure resulted in the cancellation of dozens of subsequent shuttle missions, including the next scheduled launch, STS-61-E, planned for March 6, 1986, with a payload including the ASTRO-1 observatory, which was intended to make astronomical observations of Halley's Comet. The International Comet Mission, consisting of a carrier NASA probe and a smaller European probe based on the ISEE-2 design, with the intention that the American probe would release the European probe towards Halley for a close flyby, before going on to explore Comet 10P/Tempel itself. The NASA probe was cancelled November 1979.

Presumed observations from space

*Any observations of Halley's Comet made by the crew of Soyuz T-15, which made the first trip to the

Mir ''Mir'' (, ; ) was a space station operated in low Earth orbit from 1986 to 2001, first by the Soviet Union and later by the Russia, Russian Federation. ''Mir'' was the first modular space station and was assembled in orbit from 1986 to ...

space station A space station (or orbital station) is a spacecraft which remains orbital spaceflight, in orbit and human spaceflight, hosts humans for extended periods of time. It therefore is an artificial satellite featuring space habitat (facility), habitat ...

and the last to

Salyut 7 Salyut 7 (), also known as DOS-6 (Durable Orbital Station 6) was a space station in low Earth orbit from April 1982 to February 1991. It was first crewed in May 1982 with two crew via Soyuz T-5, and last visited in June 1986, by Soyuz T-15. Va ...

in March 1986, are unknown.

References

External links

Image of Halley in 1986 by Giotto spacecraft
(ESA Giotto. Archive.org, 27 Sep 2011) {{Planetary defense Soviet space probes European Space Agency space probes NASA space probes Japanese space probes