THE SOYUZ FAMILY

Soyuz 7K-OK: (1967) Original basic model of Soyuz for earth orbit missions.
Soyuz 7K-OKS: (1971) Modification of Soyuz 7K-OK with a lightweight docking system and a crew transfer tunnel.
Soyuz 7K-T: (1973) Upgraded version of Soyuz following failure of Soyuz-11.
Soyuz 7K-M: (1973) Soyuz ferry as modified for the docking with Apollo.
Soyuz 7K-MS:
Progress: (1978) Unmanned space station supply ferry derived from Soyuz.
Soyuz T: (1979) Soyuz T represents a complete redesign of the Soyuz in the late seventies.
Soyuz TM: (1986) Purpose-built for use with Mir and follow-on space stations.
Progress M: (1989) Progress ferry with improved avionics/control and solar panels.

Soyuz is the most-utilized manned spacecraft and is now into its third decade with a flight total comparable to the aggregate for Mercury, Gemini, Apollo and Shuttle. There have also been dozens of umanned orbital tests and it is believed to form the basis of at least one type of photoreconnaissance satellite. Despite its age, Soyuz will continue in its current role as a Mir ferry and has been adopted by NASA as the interim Space Station rescue vehicle. An improved Soyuz-TM will act as the initial ACRV Assured Crew Return Vehicle for the international Space Station.

Chief designer Sergei Korolev intended there to be several Soyuz versions: the full 3-module craft for Earth-orbit operations, a stripped-down 2-module Zond for demonstrating lunar mission techniques, and a lunar-landing orbital version. The spacecraft and missions actually flown fall into three distinct categories. Soyuz 1-9 (1967-69) were configured for 3-man LEO solo missions of up to 2-1/2 weeks. Design work began on the Salyut space station in late 1969 as it became evident the Moon race was lost, and Soyuz 10-11 funtioned as crew ferries with integral transfer tunnels. The Soyuz 11 fatalities during descent prompted a thorough redesign and Soyuz became a 2-man station ferry capable of only 2-1/2 days' independent flight. The unmanned Progress cargo version was also introduced. The new design was launched 24 times in manned configuration and Soyuz 40 retired the model in May-1981. Soyuz-T with its uprated systems and 3-man crews took over for Salyut 7 operations until a further reworking produced the 'TM' Mir ferry, the designation indicating modified transport. Soyuz has thus been transformed from a spacecraft with lunar pretensions to a dedicated space station ferry.

The Soyuz has always had very limited maneuvering capability, a source of some embarrassment during the ASTP joint flight where the Apollo did most of the maneuvering. Not until the Soyuz T version was enough maneuvering fuel and the inertial navigation system available to allow rendezvous with non-cooperative objects (like the dead Salyut 7 station on the epic Soyuz T-15 flight) and to fly around objects for inspection (this is theoretically possible in the old models, but due to limited fuel or conservatism it was never demonstrated).

SOYUZ SPECIFICATIONS

First launch: 23-Apr-1967 Soyuz; 5-Jun-1980 Soyuz-T; 5-Feb-1987 Soyuz-TM
Number manned launches: 37 Soyuz, 14 Soyuz-T, 23 Soyuz-TM (to Feb-1996)
Principal uses: space station ferry, LEO solo operations
Availability: typically 2-4 launched annually
Cost: R95 million (+R56 million for SL-4) quoted in Nov-1992. R5 million quoted during Bulgarian TM5 mission of 1988, plus R4 million for SL-4 launcher
Performance: TM can accommodate a crew of three and 50 kg cargo for Mir-type operations, returning a full crew and 50 kg to Earth (no crew: 450/300 kg up/down). Independent flight time 3.2 days; attached to Mir 180 days. Capabilities are constrained partially by launch escape system. Transported equipment is limited to 45 x 60 x 100 cm up and 30 x 40 x 50 cm down
Principal units: forward Orbital Module, center Descent Module, and aft Service Module
Overall length: 6.98 m with docking probe withdrawn
Habitable volume: ~10 m³ (T/TM), previously ~9 m³
Launch mass: 7,070 kg (Soyuz-T 6,850 kg). Typically 6,790 kg at docking. Soyuz 19 mass breakdown was 1,224 kg OM, 2,802 kg DM, 2,654 kg SM
Landing mass: about 3,000 kg
Thermal protection: Soyuz-TM's exterior, apart from the SM radiators, is protected by green thermal blanketing; the DM carries eight blankets held by apex + base rings released when the other modules separates. Information on the DM's current re-entry protection is not available
Life support systems: Soyuz is hermetically sealed on the pad under sea level conditions and its 184-263 mbar partial O₂ pressure maintained by regeneration through potassium superoxide and LiOH cylinders. The bulk of the system is housed in the OM but the DM carries a smaller, independent unit. O₂ bottles provide emergency protection. Waste management and eating is handled entirely in OM; DM offers air sufficient for 48 h and only food/water packs for landing emergencies. The cosmonauts wear pressure suits
Avionics/control: the old Soyuz was controlled by ground command and/or pre-programmed analog sequencers activated from switch panels either side of the main display. Soyuz-T introduced the 16 kb-capacity Argon computer, capable of completing a fully automatic rendezvous/docking. Little is known of TM's system but it is believed to have been significantly upgraded and now supported by a backup computer. Attitude information is provided by IR Earth horizon + Sun sensors in conjunction with an improved strapped-down inertial platform. Range/range-rate information is generated by radar deployed on a 2.5 m pylon. Soyuz-TM employs the S-band Kurs docking system that allows it to approach Mir from any angle without the entire station having to rotate, as under the previous Igla system. The commander is aided by the 15^o FOV VSK-4 periscope for final approach, together with two external TV cameras

DESCENT MODULE
The decent module carries a single 70 cm diameter overhead hatch, opened from either side, and two 70 cm diameter side hatches for the primary/reserve parachute systems. The DM provides occupants with two 20 cm diameter portholes, one either side of the control panels.
Crew size: 3 (alternately, a 100 kg cargo pod can replace one crewmember)
Length: 2.2 m
Maximum diameter: 2.2 m
Habitable volume: ~4 m³
Total mass: 2,850 kg
Attitude & orbit control system
    thrusters: 6 x 67 N (activated for reentry only)
    propellant: H₂O₂
L/D hypersonic: 0.25-0.30
Power: small battery supply for power after SM separation
Landing system: On a normal mission, descent is initiated by a 3-4 min ~155 m/s retroburn by the main engine, followed by OM and then SM ejection. The landing system is activated by pressure switch at 9-11 km and 850 km/h, with two sequential stabilizing drogues releasing the 4.25 m braking 'chute from the port compartment. The primary canopy is deployed reefed at 8 km. It is freed to its full 35.5 m diameter at a descent rate of around 35 m/s to reduce sink rate to 8 m/s. The reserve systems yields 10 m/s descent rate with 25 m 'chute, activated at 6 km. The heat shield is dropped at about 3 km some 5 min before landing to clear the base retromotors for a soft landing. Four solids are triggered by a radar altimeter about 2 m above the ground to cushion the impact. Touchdown is normally on land but Soyuz is equipped for water landings

ORBITAL MODULE
The spherodial orbital module (OM) provides space for cargo, food, waste management services, orbital experimentation on solo missions and EVA operations through the 65 cm diameter side hatch. The forward 80 cm hatch houses the docking apparatus inside a 1.3 m diameter docking collar and connections for electrical, communications and hydraulic links. The original Soyuz design included four OM waist portholes, reduced to two on Soyuz-T and one on TM. Since at least 1991, TM has carried at least one front-viewing cupola in the OM, with controls for flyaround operations using direct vision.
Length: 3.0 m
Maximum diameter: 2.2 m
Habitable volume: ~6 m³
Total mass: 1,200 kg

SERVICE MODULE
The service module (SM) supports the DM on its forward face. A 45 cm deep pressurized section houses batteries, power conditioning systems for the twin solar panels and control systems. Umbilicals link this section with the DM's base panel. The unpressurized rear section holds the propulsion system and its four spherical containers; the outer surface provides a mounting for ~8 m² of thermal radiators.
Length: 2.3 m
Diameter: 2.2 m (flaring to 2.7 m at aft end)
Total mass: 2,700 kg Soyuz / 2,750 kg Soyuz-T / 2,950 kg Soyuz-TM
Propellant mass: 500 kg Soyuz / 700 kg Soyuz-T / 900 kg Soyuz-TM (some 150 kg is reserved for rendezvous/docking, and 200/400 kg is used/allocated for Earth return)
Propulsion system (old Soyuz)
    designation: KTDU-35
    main engine thrust: 4.09 kN vac (+ 4.03 kN backup)
    propellant: nitric acid/UDMH
    specific impulse: 282 s vac
    AOCS thrusters: 14 (+4 backup) x 98 N + 8 (+4 backup) x 9.8 N supplied by H₂O₂
Propulsion system (Soyuz-T, Soyuz-TM)
    designation: ODU unified propulsion system
    main engine thrust: 3.1 kN vac
    propellant: NTO/UDMH (supplies main engine + AOCS)
    specific impulse: 305 s vac
    AOCS thrusters: 14 x 137 N + 12 x 24.5 N
Power: Soyuz-T introduced twin 4-segment solar wings 1.4 x 4.4 m feeding batteries in the service module. Output ~1.3 kW, with a significant proportion lost in cabling/processing. TM span 10.6 m. Soyuz locks on to the Sun with a sensor and slowly cartwheels around the Sun axis

Soyuz separation system

External links:

• ENERGIA: Soyuz TM.
• ENERGIA: Soyuz TMA.
• ENERGIA: Soyuz TMA-M.