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Submitted by Arthur - N1ORC - Amsat #31468

The Soyuz TMA spacecraft is designed to serve as the International 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.

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 module.

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

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 activities.

This graphic highlights the Soyuz spacecraft's Descent Module.
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 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 compartment.

This graphic highlights the Soyuz spacecraft's 
Instrumentation/Propulsion Module.
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 re-entry.

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 2000.

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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