Pirs docking compartment

The "Pirs" docking compartment is a Russian module of the International Space Station (ISS). "Pirs" ( _ru. Пирс, meaning "pier") -- also called "Stikovochny Otsek 1" or "SO-1" ( _ru. Стыковочный отсек, "docking module") -- is one of the two Russian docking compartments originally planned for the ISS. "Pirs" was launched in August 2001. It provides the ISS with additional docking ports, and allows egress and ingress for spacewalks by cosmonauts using Russian Orlan space suits. When the Russian segment of the ISS was redesigned in 2001 the new design did not include SO-2, and its construction was cancelled. [cite web | url = http://www.russianspaceweb.com/iss_dc.html | title = Docking Compartment of the Russian segment of the ISS | author = Anatoly Zak] Although "Pirs" is thus the only airlock in the Russian segment of the station, spacewalks can also be conducted from the "Quest" airlock in the U.S. segment.

Construction and design

The Russian docking compartment was manufactured by RKK Energia. The Docking Compartment is similar to the Mir Docking Module used on the Mir space station. It provides docking ports for the Soyuz-TMA and Progress-M spacecraft. It also has two airlocks to accommodate spacewalks by cosmonauts wearing Russian Orlan-M spacesuits.

Launch in 2001

The 3,580 kilogram Pirs Docking Compartment is attached to the nadir (bottom, Earth-facing) port of the Zvezda service module. It docked to the International Space Station on September 16, 2001, and was configured during three spacewalks by the Expedition 3 crew.

Pirs launched Sept. 14, 2001, as ISS Assembly Mission 4R on a Russian Soyuz rocket, using a modified Progress spacecraft as an upper stage. The Docking Compartment has two primary functions. It serves as a docking port for the docking of transport and cargo vehicles to the Space Station and as an airlock for the performance of spacewalks by two Station crewmembers using Russian Orlan spacesuits.

In addition, the Docking Compartment can transport fuel from the fuel tanks of a docked Progress resupply vehicle to either the Zvezda Service Module Integrated Propulsion System or the Zarya Functional Cargo Block. It can also transfer propellant from "Zvezda" and "Zarya" to the propulsion system of docked vehicles -- Soyuz and Progress. The docking compartment's planned lifetime as part of the station was five years.

Current Status of Pirs

Pirs was originally scheduled to be discarded and reenter when the "SO2" was installed on the International Space Station, but the "SO2" has been cancelled and deleted due to lack of funding and the Pirs will continue to be used instead.Fact|date=October 2008

Future of Pirs

Pirs is scheduled to be moved from the nadir (bottom) port to the zenith (top) port of the Zvezda module to make room for the Russian Multipurpose Laboratory Module scheduled for launch in December, 2011. Cite web|url=http://www.nasa.gov/mission_pages/station/structure/iss_manifest.html|title=Consolidated Launch Manifest|accessyear=2008|accessmonthday=July 08|publisher=nasa.gov|year=2008|]

SO2 docking compartment

The SO2 docking compartment would have been installed on the Universal Docking Module (UDM). In the original design, the UDM would have been docked to the nadir (Earth-facing) port of "Zvezda" SO2 would have been docked to one of the UDM's four docking ports, as would each of the two Russian Research Modules. The SO2 and one Research Module have since been cancelled, and the UDM itself has been replaced by the Multipurpose Laboratory Module.

Pirs Docking Compartment — airlock specifications

*Length: 4.91 meters
*Diameter: 2.55 meters
*Weight: 3,580 kilograms
*Volume: 13 cubic meters

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References