Soyuz spacecraft

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Soyuz TMA spacecraft

Soyuz diagram

Soyuz (Russian: Союз, pronounced sah-YOUS, meaning "union") is a series of spacecraft designed by Sergey Korolyov for the Soviet Union's space program. The Soyuz succeeded the Voskhod spacecraft design and were originally built as part of the Soviet Manned Lunar program. The first unmanned launch of the Soyuz was on November 28, 1966. The first manned launch of the Soyuz was on April 23, 1967. Currently, the Soyuz spacecraft family is still in service and has launched more manned space missions than any other platform. The Soyuz spacecraft is launched by the Soyuz launch vehicle, as part of the Soyuz program and in the later missions as part of the Zond program. They were later used to carry cosmonauts to and from the Salyut and Mir space stations and are now used for transport to and from the International Space Station.

[edit] Design

Diagram showing the three elements of the Soyuz-TMA spacecraft.

A Soyuz spacecraft consists of three parts (from front to back):

a spheroid orbital module

a small aerodynamic reentry module

a cylindrical service module with solar panels attached

The first two portions are habitable living space. By moving as much as possible into the orbital module, which does not have to be shielded or decelerated during atmospheric re-entry, the Soyuz is both larger and lighter than the Apollo spacecraft's command module. The Apollo command module had six cubic meters of living space and a mass of 5000 kg; the three-part Soyuz provided the same crew with nine cubic meters of living space, an airlock, and a service module for the mass of the Apollo capsule alone.

Soyuz can carry up to three cosmonauts and provide life support for them for about 30 person days. The life support system provides a nitrogen/oxygen atmosphere at sea level partial pressures. The atmosphere is regenerated through KO₂ cylinders, which absorb most of the CO₂ and water produced by the crew and regenerates the oxygen, and LiOH cylinders which absorb leftover CO₂.

The vehicle is protected during launch by a nose fairing, which is jettisoned after passing through the atmosphere. It has an automatic docking system. The ship can be operated automatically, or by a pilot independently of ground control.

[edit] Orbital Module

Soyuz spacecraft's Orbital Module

The forepart of the spacecraft is the orbital module. It houses all the equipment that will not be needed for reentry, such as experiments, cameras or cargo. Commonly, it is used as both dining area and lavatory. At its far end, it also contains the docking port.

A hatch between it and the descent module can be closed so as to isolate it to act as an airlock if needed, cosmonauts exiting through its side port (at the bottom of this picture, near the descent module). On the launch pad, they have entered the spacecraft through this port.

This separation also lets the orbital module be customized to the mission with less risk to the life-critical descent module. The convention of orientation in zero gravity differs from that of the descent module, as cosmonauts stand or sit with their heads to the docking port.

[edit] Reentry Module

Soyuz spacecraft's Descent Module

The reentry module is used for launch and the journey back to Earth. It is covered by a heat-resistant covering to protect it during re-entry. It is slowed initially by the atmosphere, then by a braking parachute, followed by the main parachute which slows the craft for landing. At one meter above the ground, solid-fuel braking engines mounted behind the heat shield are fired to give a soft landing. One of the design requirements for the reentry module was for it to have the highest possible volumetric efficiency (internal volume divided by hull area). The best shape for this is a sphere, but such a shape can provide no lift, which results in a purely ballistic reentry. Ballistic reentries are hard on the occupants due to high deceleration and can't be steered beyond their initial deorbit burn. That is why it was decided to go with the 'headlight' shape that the Soyuz uses - a hemispherical forward area joined by a barely angled conical section (seven degrees) to a classic spherical section heat shield. This shape allows a small amount of lift to be generated due to the unequal weight distribution. The nickname was thought up at a time when nearly every headlight was circular.

[edit] Service Module

Soyuz spacecraft's Instrumentation/Propulsion Module

At the back of the vehicle is the service module. It has a pressurized container shaped like a bulging can that contains systems for temperature control, electric power supply, long-range radio communications, radio telemetry, instruments for orientation and control. A non-pressurized part of the service module contains the main engine and a spare: liquid-fuel propulsion systems for maneuvering in orbit and initiating the descent back to Earth. The ship also has a system of low-thrust engines for orientation. Outside the service module are the sensors for the orientation system and the solar array, which is oriented towards the sun by rotating the ship.

[edit] Technical Data

[edit] Variants

[edit] A-B-C circumlunar complex (1963)

Soyuz-A manned spacecraft concept (1963). It was to have been part of the Soyuz A-B-C circumlunar complex Soyuz A-B-C circumlunar concept. The drawing shows Soyuz-A (right), Soyuz-B booster, and Soyuz-C tanker with twin whip antennae (left)

Korolev initially promoted the Soyuz A-B-C circumlunar complex concept in which a two-man craft would rendezvous with other components in Earth orbit to assemble a lunar excursion vehicle, the components being delivered by the proven R-7 rocket. Besides the Soyuz-A spacecraft, the complex would feature a Soyuz-B booster and a Soyuz-C tanker with twin whip antennae.

[edit] Soyuz 7K-OK (1967-1971)

Soyuz 7K-OK(A) spacecraft with an active docking unit.

The manned Soyuz spacecraft can be classified into design generations. Soyuz 1 through Soyuz 11 (1967-1971) were first-generation vehicles, carrying a crew of up to three without spacesuits and distinguished from those following by their bent solar panels and their use of the Igla automatic docking navigation system, which required special radar antennas. This first generation was called 7K-OK and encompassed the original Soyuz and Salyut 1 Soyuz. Variations within it were primarily docking fixtures; the first nine examples had no internal hatch and crew transfer had to take place by means of spacewalks, employing spacesuits kept in the orbital module, which functioned as an airlock, as done on Soyuz 4 and 5.

[edit] Soyuz 7K-L1 (1967-1970)

The 7K-L1 was designed to launch men from the Earth to circle the moon. It was based on the 7K-OK with several components stripped out to reduce the vehicle weight. The most notable modifications included the removal of the orbital module (providing extra space for living quarters or equipment) and a reserve parachute. It was the primary hope for Soviet circumlunar flight. Tests in the Zond program from 1968-1970 (Zond 4 to Zond 8) produced multiple failures in the 7K-L1's re-entry systems. The goal was scrapped, along with the two remaining 7K-L1s.

[edit] Soyuz 7K-OKS

Upgraded Soyuz 7K-T version capable of carrying 2 cosmonauts with Sokol space suits (after the Soyuz 11 accident).

The next manned version of the Soyuz was the 7K-OKS

This was designed for space station flights and now had a docking port that allowed internal transfer between spacecraft. It flew only twice manned (Soyuz 10 and Soyuz 11). During the reentry of the second flight, Soyuz 11, the crew were killed when the capsule depressurized during the re-entry phase.

[edit] Soyuz 7K-T (1973-1981)

Salyut 1-type Soyuz 7K-T for 3 cosmonauts without space suits. This was the Original Soyuz 7K-OK upgraded for Salyut space stations. The probe and drogue docking system (left) permitted internal transfer of cosmonauts from the Soyuz to the station.

The second generation, the Soyuz Ferry, comprised Soyuz 12 through Soyuz 40 (1973-1981). Although still using the Igla system, these had no solar panels, employing batteries; the crew could now wear spacesuits throughout their flight, though their number was reduced to two.

This version is called the 7K-T. With just a crew of two, all cosmonauts could wear spacesuits during launch and reentry. The replacement of solar panels with batteries limited it to about two days of undocked flight.

A modified version of this spacecraft flew on Soyuz 13, were instead of the docking system a large Orion 2 astrophysical camera for imaging the sky and Earth was used.

Another modification was the 7K-T/A9 used for the flights to the military Almaz space station. This featured the ability to remote control the space station and a new parachute system and other still classified and unknown changes.

[edit] Soyuz-T (1976-1986)

Soyuz-T spacecraft. Apollo-Soyuz Test Project (ASTP) Soyuz. The APAS-75 docking unit is located at left.

Apollo-Soyuz Test Project Soyuz served as a technological bridge to the third generation Soyuz-T (T - транспортный, Transportnyi meaning transport) spacecraft (1976-1986). It featured solar panels allowing longer missions, a revised Igla rendezvous system and new translation/attitude thruster system on the Service module. It could carry a crew of three, now wearing spacesuits.

The Soyuz ASTP spacecraft was designed for use during the Apollo Soyuz Test Project. It featured design changes mandated by the Americans to make the spacecraft safer. The Soyuz ASTP featured new solar panels for increased mission length, an androgynous universal docking mechanism instead of the standard male mechanism and modifications to the environmental control system to lower the cabin pressure to 0.68 atmospheres (69 kPa) prior to docking with Apollo. The last flight of this version, Soyuz 22 again replaced the docking port with a camera.

[edit] Soyuz-TM (1986-2003)

Soyuz-TM spacecraft. Compare the antennae on the orbital module to those on Soyuz-T. Differences reflect the change from the Igla rendezvous system used on Soyuz-T to the Kurs rendezvous system used on Soyuz-TM.

Soyuz-TM crew transports (M - модифицированный, Modifitsirovannyi meaning modified) was fourth generation (1986-2003) and used for ferry flights to the Mir and ISS space stations. It added to the Soyuz T new docking and rendezvous, radio communications, emergency and integrated parachute/landing engine systems. The new Kurs rendezvous and docking system permitted the Soyuz TM to maneuver independently of the station, without the station making "mirror image" maneuvers to match unwanted translations introduced by earlier models' aft-mounted attitude control.

[edit] Soyuz-TMA (2003-.... )

The Soyuz TMA-7 spacecraft departs from the International Space Station.

A slightly modified Soyuz TMA is now also being used (A - антропометрический, Antropometricheskii meaning anthropometric). This features several changes to accommodate requirements requested by NASA in order to service the International Space Station, including more latitude in the height and weight of the crew and improved parachute systems. It is also the first expendable vehicle to feature "glass cockpit" technology, and the first of the Soyuz spacecraft family to have the feature. Soyuz-TMA looks identical as a Soyuz-TM spacecraft on the outside, but in the interior, it is able to accommodate taller occupants with new adjustable crew couches.

[edit] Future developments

In 2004, Russian space officials announced that the Soyuz will be replaced by early 2011 with the new Kliper and Parom spacecrafts. However, since then the Kliper appears to have been indefinitely postponed due to lack of funding from government, and it has been announced that the Soyuz will receive an upgrade to make it suitable for missions beyond Earth orbit.

[edit] Related craft

The unmanned Progress spacecraft were derived from Soyuz and are used for servicing space stations.

The Chinese Shenzhou spacecraft is also heavily influenced by the design of the Soyuz.

[edit] See also

• Progress spacecraft
• Sokol space suit
• space exploration
• human spaceflight
• Crew Space Transportation System study to develop a European-Russian successor to Soyuz

[edit] Missions

See List of manned space missions as well as the Zond program

[edit] Image Gallery

Early 7K-OK Soyuz at National Space Centre, Leicester, England	Soyuz spacecraft of the Apollo Soyuz Test Project (ASTP)	Soyuz 19 spacecraft as seen from Apollo CM	Soyuz docked to Mir
Soyuz spacecraft mock-up	Soyuz launch vehicles engines	Soyuz TM-31 Moves to Launch Pad, 29 October 2000	Soyuz TMA-2 launch, Baikonur, April 26, 2003
Soyuz TMA-3 landing (NASA)	Space Shuttle Orbiter and Soyuz-TM (drawn to scale). Current spacecraft used by humans to travel in space.

[edit] External links

• Russia New Russian spaceship will be able to fly to Moon - space corp
• RSC Energia: Concept Of Russian Manned Space Navigation Development
• David S.F. Portree, Mir Hardware Heritage, NASA RP-1357, 1995
• Information on Soyuz spacecraft (search for Soyuz on that page for links to every spacecraft imaginable)
• OMWorld's ASTP Docking Trainer Page
• NASA - Russian Soyuz TMA Spacecraft Details

v • d • e Soviet (to 1991) and Russian government manned space programs
Active:	Soyuz - ISS (joint)
In Development:	Kliper
Past	Vostok, Voskhod, Salyut, Apollo-Soyuz Test Project (joint), Mir, Shuttle-Mir Program (joint)
Cancelled	Zond (lunar Soyuz 7K-L1) - N1-L3 (Moon landing program) - Spiral - Almaz (incorporated into Salyut program) / TKS spacecraft - Energia / Buran

v • d • e Lunar Manned Spacecraft
Orbiters	Apollo Command/Service Module, Soyuz spacecraft/Lunniy Orbitalny Korabl, Orion
Landers	Apollo Lunar Module, Lunniy Korab, Lunar Surface Access Module

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