Sistema Stykovki i Vnutrennego Perekhoda, SSVP (russian: Система стыковки и внутреннего перехода, ''System for docking and internal transfer'') is a docking standard used by

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

and

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...

n spacecraft, sometimes called RDS for ''Russian Docking System''. It has been used on all variants of

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

other than the Soyuz 7K-L3 and early flights of the Soyuz 7K-OK, as well as

Progress Progress is the movement towards a refined, improved, or otherwise desired state. In the context of progressivism, it refers to the proposition that advancements in technology, science, and social organization have resulted, and by extension w ...

, TKS,

ATV ATV may refer to: Broadcasting * Amateur television *Analog television Television stations and companies * Ràdio i Televisió d'Andorra * ATV (Armenia) * ATV (Aruba), NBC affiliate * ATV (Australian TV station), Melbourne * ATV (Austria) * AT ...

, and on all Soviet and Russian

space station A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station ...

History

SSVP was initially conceived in 1967 by the TsKBEM design bureau for use on the then-planned OIS military space station. Though OIS never flew, in 1970 the design was selected for use on the

Salyut The ''Salyut'' programme (russian: Салют, , 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 ...

and

Almaz The Almaz (russian: Алмаз, lit=Diamond) program was a highly secret Soviet military space station program, begun in the early 1960s. Three crewed military reconnaissance stations were launched between 1973 and 1976: Salyut 2, Salyut 3 ...

space stations. During its first attempted use on the Soyuz 10 mission, docking was unsuccessful due to a faulty hatch, and a failure in the automatic docking system. This led to a number of redesigns to reduce damage from accidental loads. In the 1980s, SSVP was further upgraded to support docking of large modules, such as the ones that would be used to construct '' Mir''. They were used to attach all pressurized modules of the ''Mir'', and for most spacecraft dockings (with the exception of the

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...

flights, and Soyuz TM-16, which used the APAS-89 docking mechanisms located on Kristall and the

Mir Docking Module The Stykovochnyy Otsek (russian: стыковочный отсек, en, Docking compartment), GRAU index 316GK, otherwise known as the ''Mir'' docking module or SO, was the sixth module of the Russian space station '' Mir'', launched in November ...

.) The modern version of SSVP is SSVP-G4000. The Russian segment of the

International Space Station The International Space Station (ISS) is the largest Modular design, modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos ( ...

features eight available passive SSVP-G4000 ports, located on Zvezda-aft, Rassvet, Poisk, and

Prichal ''Prichal'' nodal module also known as Uzlovoy Module or UM (russian: Узловой Модуль "Причал", ''Nodal Module Berth'') is a Russian spacecraft which is part of the International Space Station (ISS). It was approved in 201 ...

. An additional port, on Zarya-nadir, was used to dock Rassvet. In addition to Russian spacecraft, the SSVP was also used on the European

Automated Transfer Vehicle The Automated Transfer Vehicle, originally Ariane Transfer Vehicle or ATV, was an expendable automated cargo spacecraft, cargo spacecraft developed by the European Space Agency (ESA), used for space cargo transport in 2008–2015. The ATV desi ...

, which docked to the aft port of Zvezda. These ports were provided by

in exchange for the Data Management System, supplied by ESA for use in Zvezda. An upgraded version, designed for reusability and to provide a wider tunnel, is planned for use on the next-generation Orel spacecraft.

Design

SSVP consists of two components; an active probe, and a passive drogue. The probe enters the drogue, and its tip is grasped by soft-capture latches which are then retracted using electrically driven motors to provide close alignment. Eight hard-capture locks then firmly attach the two spacecraft. After hard docking, the pressure between spacecraft is equalized using the Interface Leak Check System. The port contains a transfer tunnel, with an internal diameter of 800 mm. The ring surrounding this tunnel also includes a number of connectors, providing for transfer of power, data, and fuel between two docked vehicles.

Hybrids

A "hybrid" version, combining the design of SSVP and

APAS-95 The terms Androgynous Peripheral Attach System (APAS), Androgynous Peripheral Assembly System (APAS) and Androgynous Peripheral Docking System (APDS), are used interchangeably to describe a family of spacecraft docking mechanisms, and are also so ...

, is also available, used for permanent docking of space station modules. This version uses the probe-and-drogue design of the standard SSVP, but with a hard-dock collar from APAS-95. The APAS-95 collar has twelve latches instead of the eight of standard SSVP. This variant is known as SSVP-M8000. These hybrid SSVP ports are used to permanently connect Pirs, Nauka, Poisk and Zarya to Zvezda and Prichal to Nauka. Modified Passive hybrids of SSVP-M8000 are used on lateral ports of Prichal and are known as SSPA-GB 1/2.

Adapter Ring

It converts passive Hybrid SSVP-M8000 Docking System to passive SSVP-G4000. The docking ring initially used for Soyuz MS-18 and

Progress MS-17 Progress MS-17 (), Russian production No. 446, identified by NASA as Progress 78P, was a Progress spaceflight operated by Roscosmos to resupply the International Space Station (ISS). This was the 169th flight of a Progress spacecraft. History ...

docking on Nauka until detached by Progress MS-17 inflight for Prichal module arrived on ISS. This adapter is termed as SSPA-GM. It was made for the Nauka nadir and Prichal nadir ports of the International Space Station, where Soyuz and Progress spacecrafts had to dock to a port designated for modules. Before removal of SSPA-GM, the docking ring is in diameter; that becomes after removal.

References

External links