Progress 7K-TG (,

GRAU index The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the Chief of ...

11F615A15), was a

Soviet 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 ...

uncrewed spacecraft used to resupply

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 ...

s in

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

. Forty three flew, delivering cargo to

Salyut 6 Salyut 6 () was a Soviet orbital space station, the eighth station of the Salyut programme, and alternatively known DOS-5 as it was the fifth of the Durable Orbital Station series of civilian space stations. It was launched on 29 September 19 ...

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 ...

, and

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 ...

. It was the first version of the

Progress Progress is movement towards a perceived refined, improved, or otherwise desired state. It is central to the philosophy of progressivism, which interprets progress as the set of advancements in technology, science, and social organization effic ...

spacecraft to fly, and spawned later derivatives including the Progress-M which replaced it, and the later Progress-M1. Model of Salyut-7 with two Soyuz spacecrafts

Model of Salyut-7 with two Soyuz spacecrafts

The Progress 7K-TG spacecraft was derived from the crewed

Soyuz 7K-T The second generation of the Soyuz spacecraft, the ''Soyuz 7K-T'', comprised Soyuz 12 through Soyuz 40 (1973–1981). In the wake of the Soyuz 11 tragedy, the spacecraft was redesigned to accommodate two cosmonauts who would wear pressure ...

ferry spacecraft, which had been designed for the

Salyut programme The ''Salyut'' programme (, , meaning "salute" or "fireworks") was the first space station programme, undertaken by the Soviet Union. It involved a series of four crewed scientific research space stations and two crewed military reconnaissa ...

. The descent module of the Soyuz spacecraft was replaced with a new section designated ''Otsek Komponentov Dozapravki'', or OKD. This contained fuel tanks and pumps used for refuelling the space station that it docked with. Like the Soyuz 7K-T, the Progress was not equipped with

solar panels A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

, and instead relied on batteries for power. Early spacecraft had a design life of 33 days, including three in free flight, and the rest docked with a space station. Later spacecraft flew longer missions, with the longest, Progress 38, spending almost 75 days in orbit. The first Progress 7K-TG spacecraft, Progress 1, was launched on 20 January 1978. The first twelve spacecraft flew to Salyut 6, with the next thirteen, including the Kosmos 1669 spacecraft - a Progress spacecraft which was given a Kosmos designation and omitted from the sequence of Progress designations - going to Salyut 7. The last eighteen flew to Mir. With the exception of Progress 20, all of the flights to Salyut stations were launched by

Soyuz-U Soyuz-U ( GRAU index: 11A511U) was a Soviet and later Russian expendable medium-lift launch vehicle designed by the TsSKB design bureau and constructed at the Progress factory in Samara, Russia. The ''U'' designation stands for ''unified' ...

carrier rockets. Progress 20 and all of the Mir flights used the more powerful Soyuz-U2 carrier rocket. The last spacecraft, Progress 42, was launched on 5 May 1990. It was deorbited on 27 May 1990, breaking up in the atmosphere over the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

at around 12:27 UTC. Some Progress 7K-TG launches used the payload fairing developed for the

Soyuz Soyuz is a transliteration of the Cyrillic text Союз (Russian language, Russian and Ukrainian language, Ukrainian, 'Union'). It can refer to any union, such as a trade union (''profsoyuz'') or the Soviet Union, Union of Soviet Socialist Republi ...

spacecraft, including the launch escape tower, but with the motors in the tower removed, and no stabilisers on the sides of the fairing. Officially this was done to preserve the rocket's aerodynamic properties, however it was reported that on several flights the tower was used to support tests of the K-36M

ejection seat In aircraft, an ejection seat or ejector seat is a system designed to rescue the aircraft pilot, pilot or other aircrew, crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an exp ...

under development for the

Buran programme The ''Buran'' programme (, , "Snowstorm", "Blizzard"), also known as the "VKK Space Orbiter programme" (), was a Soviet and later Russian reusable spacecraft project that began in 1974 at the Central Aerohydrodynamic Institute in Moscow and w ...

. In addition to their regular cargoes, the Progress 7 spacecraft was used to transport the KRT-10

radio telescope A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the r ...

to Salyut 6, and Progress 17 delivered the Iskra 3 satellite to Salyut 7 for deployment.

References

{{DEFAULTSORT:7K-TG, Progress Progress (spacecraft)

See also

References