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Submitted by Arthur - N1ORC
Space Station Assembly
Elements: Russian Soyuz

The Soyuz TMA spacecraft is designed to serve as the space station's crew
return vehicle, acting as a lifeboat in the unlikely event an emergency
would require the crew to leave the station. A new Soyuz capsule is
normally delivered to the station by a Soyuz taxi crew every six months
-- the taxi crew then returns to Earth in the older Soyuz capsule.

The Soyuz spacecraft is launched to the space station from the Baikonur
Cosmodrome in Kazakhstan aboard a Soyuz rocket. It consists of an Orbital
Module, a Descent Module and an Instrumentation/Propulsion Module.

Orbital Module

This graphic highlights the Soyuz spacecraft's Orbital Module. 
This portion of the Soyuz spacecraft is used by the crew while on orbit
during free-flight. It has a volume of 6.5 cubic meters (230 cubic feet),
with a docking mechanism, hatch and rendezvous antennas located at the
front end. The docking mechanism is used to dock with the space station
and the hatch allows entry into the station. The rendezvous antennas are
used by the automated docking system -- a radar-based system -- to
maneuver towards the station for docking. There is also a window in the

The opposite end of the Orbital Module connects to the Descent Module via
a pressurized hatch. Before returning to Earth, the Orbital Module
separates from the Descent Module -- after the deorbit maneuver -- and
burns up upon re-entry into the atmosphere.

Descent Module

This graphic highlights the Soyuz spacecraft's Descent Module.
The Descent Module is where the cosmonauts and astronauts sit for launch,
re-entry and landing. All the necessary controls and displays of the
Soyuz are located here. The module also contains life support supplies
and batteries used during descent, as well as the primary and backup
parachutes and landing rockets. It also contains custom-fitted seat
liners for each crewmember's couch/seat, which are individually molded to
fit each person's body -- this ensures a tight, comfortable fit when the
module lands on the Earth. When crewmembers are brought to the station
aboard the space shuttle, their seat liners are brought with them and
transferred to the existing Soyuz spacecraft as part of crew handover

The module has a periscope, which allows the crew to view the docking
target on the station or the Earth below. The eight hydrogen peroxide
thrusters located on the module are used to control the spacecraft's
orientation, or attitude, during the descent until parachute deployment.
It also has a guidance, navigation and control system to maneuver the
vehicle during the descent phase of the mission.

This module weighs 2,900 kilograms (6,393 pounds), with a habitable
volume of 4 cubic meters (141 cubic feet). Approximately 50 kilograms
(110 pounds) of payload can be returned to Earth in this module and up to
150 kilograms (331 pounds) if only two crewmembers are present. The
Descent Module is the only portion of the Soyuz that survives the return
to Earth.

Instrumentation/Propulsion Module

This graphic highlights the Soyuz spacecraft's Instrumentation/Propulsion
This module contains three compartments: Intermediate, Instrumentation
and Propulsion.

The intermediate compartment is where the module connects to the Descent
Module. It also contains oxygen storage tanks and the attitude control
thrusters, as well as electronics, communications and control equipment.
The primary guidance, navigation, control and computer systems of the
Soyuz are in the instrumentation compartment, which is a sealed container
filled with circulating nitrogen gas to cool the avionics equipment. The
propulsion compartment contains the primary thermal control system and
the Soyuz radiator, which has a cooling area of 8 square meters (86
square feet). The propulsion system, batteries, solar arrays, radiator
and structural connection to the Soyuz launch rocket are located in this

The propulsion compartment contains the system that is used to perform
any maneuvers while in orbit, including rendezvous and docking with the
space station and the deorbit burns necessary to return to Earth. The
propellants are nitrogen tetroxide and unsymmetric-dimethylhydrazine. The
main propulsion system and the smaller reaction control system, used for
attitude changes while in space, share the same propellant tanks.

The two Soyuz solar arrays are attached to either side of the rear
section of the Instrumentation/Propulsion Module and are linked to
rechargeable batteries. Like the Orbital Module, the intermediate section
of the Instrumentation/Propulsion Module separates from the Descent
Module after the final deorbit maneuver and burns up in atmosphere upon

Rendezvous, Docking and Undocking

A Soyuz spacecraft generally takes two days after launch to reach the
space station. The rendezvous and docking are both automated, though once
the spacecraft is within 150 meters (492 feet) of the station, the
Russian Mission Control Center just outside Moscow monitors the approach
and docking. The Soyuz crew has the capability to manually intervene or
execute these operations.

TMA Improvements and Testing

The Soyuz TMA spacecraft is a replacement for the Soyuz TM, which was
used from May 1986 to November 2002 to take astronauts and cosmonauts to
Mir and then to the International Space Station beginning in November

The TMA increases safety, especially in descent and landing. It has
smaller and more efficient computers and improved displays. In addition,
the Soyuz TMA accommodates individuals as large as 1.9 meters (6 feet, 3
inches tall) and 95 kilograms (209 pounds), compared to 1.8 meters (6
feet) and 85 kilograms (187 pounds) in the earlier TM. Minimum crewmember
size for the TMA is 1.5 meters (4 feet, 11 inches) and 50 kilograms (110
pounds), compared to 1.6 meters (5 feet, 4 inches) and 56 kilograms (123
pounds) for the TM.

Two new engines reduce landing speed and forces felt by crewmembers by 15
to 30 percent and a new entry control system and three-axis accelerometer
increase landing accuracy. Instrumentation improvements include a color
"glass cockpit," which is easier to use and gives the crew more
information, with hand controllers that can be secured under an
instrument panel. All the new components in the Soyuz TMA can spend up to
one year in space.

New components and the entire TMA were rigorously tested on the ground,
in hangar-drop tests, in airdrop tests and in space before the spacecraft
was declared flight-ready. For example, the accelerometer and associated
software, as well as modified boosters (incorporated to cope with the
TMA's additional mass), were tested on flights of Progress unpiloted
supply spacecraft, while the new cooling system was tested on two Soyuz
TM flights.

Descent module structural modifications, seats and seat shock absorbers
were tested in hangar drop tests. Landing system modifications, including
associated software upgrades, were tested in a series of airdrop tests.
Additionally, extensive tests of systems and components were conducted on
the ground.


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