Zvezda (ISS)
Encyclopedia
Zvezda DOS-8, also known as the Zvezda Service Module, is a component of the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...

 (ISS). It was the third module launched to the station, and provides all of the station's life support system
Life support system
In human spaceflight, a life support system is a group of devices that allow a human being to survive in space.US government space agency NASA,and private spaceflight companies...

s, some of which are supplemented in the USOS, as well as living quarters for two crew members. It is the structural and functional center of the Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

n portion of the station - the Russian Orbital Segment
Russian Orbital Segment
The Russian Orbital Segment is the name given to the components of the International Space Station constructed in Russia and operated by the Russian Federal Space Agency...

.

The module was manufactured by S.P. Korolev Rocket and Space Corporation Energia
S.P. Korolev Rocket and Space Corporation Energia
OAO S.P. Korolev Rocket and Space Corporation Energia , also known as RKK Energiya, is a Russian manufacturer of spacecraft and space station components...

. Zvezda was launched on a Proton rocket on July 12, 2000 and docked with the Zarya module on July 26. The rocket used for the launch was one of the first to carry advertising
Space advertising
Space advertising is the use of advertising in outer space or related to space flight. While there have only been a few examples of successful marketing campaigns, there have been several proposals to advertise in space, some even planning to launch giant billboards visible from the Earth...

; it was emblazoned with the logo
Logo
A logo is a graphic mark or emblem commonly used by commercial enterprises, organizations and even individuals to aid and promote instant public recognition...

 of the fast food
Fast food
Fast food is the term given to food that can be prepared and served very quickly. While any meal with low preparation time can be considered to be fast food, typically the term refers to food sold in a restaurant or store with preheated or precooked ingredients, and served to the customer in a...

 chain Pizza Hut
Pizza Hut
Pizza Hut is an American restaurant chain and international franchise that offers different styles of pizza along with side dishes including pasta, buffalo wings, breadsticks, and garlic bread....

, for which the company is reported to have paid more than US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

1 million.

Origins

The basic structural frame of Zvezda, known as "DOS-8", was initially built in the mid-1980s to be the core of the Mir-2
Mir-2
Mir-2 was a space station project begun in February 1976. Some of the modules built for Mir-2 have been incorporated into the International Space Station . The project underwent many changes, but was always based on the DOS-8 base block space station core module, built as a back-up to the DOS-7...

space station. This means that Zvezda is similar in layout to the core module (DOS-7) of the Mir
Mir
Mir was a space station operated in low Earth orbit from 1986 to 2001, at first by the Soviet Union and then by Russia. Assembled in orbit from 1986 to 1996, Mir was the first modular space station and had a greater mass than that of any previous spacecraft, holding the record for the...

space station. It was in fact labeled as "Mir-2" for quite some time in the factory. Its design lineage thus extends back to the original Salyut
Salyut
The Salyut program was the first space station program undertaken by the Soviet Union, which consisted of a series of nine space stations launched over a period of eleven years from 1971 to 1982...

 stations. The space frame was completed in February 1985 and major internal equipment was installed by October 1986.

The MIR-2 space station was redesigned after the failure of the Polyus core module to reach orbit. Zvezda is around 1/4 the size of polyus, and has no armaments.

Design

Zvezda consists of a cylindrical "Work Compartment" where the crews work and live, a cylindrical "Transfer Chamber" which has one docking port, an unpressurized "Assembly Compartment" surrounding the Transfer Chamber, and a spherical "Transfer Compartment" with three docking ports. The component weights 18051 kg (39,795.6 lb)) and had a length of 13.1 metres (43 ft). The solar panels extend 29.7 metres (97.4 ft).

The "Transfer Compartment" attaches to the Zarya module, and has docking ports intended for the Science Power Platform
Science Power Platform
The Science Power Platform was a planned Russian element of the International Space Station that was intended to be delivered to the ISS by a Russian Proton rocket or Zenit rocket but was shifted to launch by Space Shuttle as part as a tradeoff agreement on other parts of the ISS...

 and the Universal Docking Module
Universal Docking Module
The Nodal Module is a pressurized module of the Russian Segment of the International Space Station and will be used in the OPSEK space station...

. As in the early days of Mir, the transfer compartment provides a suitable EVA airlock where spacewalkers in Orlan suits removed a hatch after closing a few that connected the compartment to the rest of the station. It was used only during Expedition 2
Expedition 2
Expedition 2 was the second long-duration spaceflight aboard the International Space Station, immediately following Expedition 1. Its three person crew stayed aboard the station from March to August 2001...

, where two men put a docking cone on the nadir port. Currently the lower port contains the Pirs Docking Compartment and the other contains Mini-Research Module 2. In December 2011, Pirs will be deorbited and replaced by the Multipurpose Laboratory Module
Multipurpose Laboratory Module
Nauka , also known as the Multipurpose Laboratory Module , , will be a component of the International Space Station , funded by the Russian Federal Space Agency. In the original ISS plans, Nauka was to use the location of the Docking and Stowage Module...

.

The "Assembly Compartment" holds external equipment such as thrusters, thermometers, antennas, and propellant tanks.

The "Transfer Chamber" is equipped with automatic docking equipment and is used to service Soyuz
Soyuz spacecraft
Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...

 and Progress spacecraft
Progress spacecraft
The Progress is a Russian expendable freighter spacecraft. The spacecraft is an unmanned resupply spacecraft during its flight but upon docking with a space station, it allows astronauts inside, hence it is classified manned by the manufacturer. It was derived from the Soyuz spacecraft, and is...

.

Zvezda contains sleeping quarters for two cosmonauts, a NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

-provided Treadmill with Vibration Isolation System
Treadmill with Vibration Isolation System
The Treadmill with Vibration Isolation Stabilization System, commonly abbreviated as TVIS, is a treadmill for use on-board the International Space Station and is designed to allow astronauts to run without vibrating delicate microgravity science experiments in adjacent labs...

 and a bicycle for exercise, toilet and other hygiene facilities and a galley with a refrigerator and freezer. It contains the primary Russian computers for guidance and navigation. It has a total of 14 windows—three 9 inches (228.6 mm) windows in the forward Transfer Compartment, a 16-inch window in the Working Compartment, one in each crew compartment, and several more. It also contains the Elektron system that electrolyzes condensed humidity and waste water to provide hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. The hydrogen is expelled into space and the oxygen is used for breathing air. The condensed water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 and the waste water can be used for drinking in an emergency, but ordinarily fresh water from Earth is used. There are 16 small thrusters and two large thrusters for propulsion, and eight batteries for storing power.

The Elektron system has required significant maintenance work, having failed several times and requiring the crew to use Solid Fuel Oxygen Generator canisters (commonly called "Oxygen Candles", which were the cause of a fire on Mir) when it has been broken for extended amounts of time. It also contains the Vozdukh, a system which removes carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 from the air based on the use of regenerable absorbers of carbon dioxide gas. Zvezda has been criticized for being excessively noisy and the crew has been observed wearing earplugs inside it.

Connection to the ISS

On July 26, 2000, Zvezda became the third component of the ISS when it docked at the aft port of Zarya. (Zarya had already been attached to the U.S. Unity module
Unity Module
thumb|right|300px|ISS Unity connecting module The Unity connecting module was the first U.S.-built component of the International Space Station....

.) Later in July, the computers aboard Zarya handed over ISS commanding functions to computers on Zvezda.

On September 11, 2000, two members of the STS-106
STS-106
STS-106 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Atlantis.-Crew:-Mission parameters:*Mass:**Orbiter Liftoff: **Orbiter Landing: **Payload: *Perigee: 233 mi...

 Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

 crew completed final connections between Zvezda and Zarya; during a 6 hour, 14 minute EVA, astronaut Ed Lu and cosmonaut Yuri Malenchenko connected nine cables between Zvezda and Zarya, including four power cables, four video and data cables and a fiber-optic telemetry cable. The next day, STS-106 crew members floated into Zvezda for the first time, at 05:20 UTC on September 12, 2000.

Zvezda provided early living quarters, a life support system, a communication system (Zvezda introduced a 10 Mbit/s Ethernet network to the ISS), electrical power distribution, a data processing system, a flight control system, and a propulsion system. These quarters and some, but not all, systems have since been supplemented by additional ISS components.

The two main engines on Zvezda can be used to raise the station's altitude. This was done on April 25, 2007. This was the first time the engines had been fired since Zvezda arrived in 2000.

Launch risks

Due to Russian financial problems, Zvezda was launched with no backup and no insurance. Due to this risk, NASA had constructed an Interim Control Module
Interim Control Module
The Interim Control Module is a NASA constructed module designed to serve as a temporary "tug" for the International Space Station in case the Zvezda service module was destroyed or not launched for an extended period of time. It was derived from a formerly-classified Titan Launch Dispenser used...

in case it was delayed significantly or destroyed on launch.
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