Mir Hardware Heritage/Part 3 - Space Station Modules

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3.1 General Description
The heritage of the space station modules joined to Mir is convoluted (figure 3-1). In all cases, however, they are based on a “universal block,” a vehicle referred to by the Russian acronym FGB (figure 3-2).

For our purposes, we can group FGB-based vehicles into three categories:
 * Transport Logistics Spacecraft (Russian acronym TKS) (1976-1983)
 * Space station modules (1985-present)
 * Space tugs (1987-present)

All these categories have in common the following “predesigned systems.”


 * Basic FGB structure, including pressurized volume


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 * Rendezvous and docking systems
 * ΔV engines
 * Thrusters and attitude control systems
 * Propellant tanks
 * Power systems
 * Guidance and control systems
 * Thermal control systems

To form the vehicles in the different categories, the common predesigned systems are grouped or modified in various ways. Modifications are made in
 * Location of engines
 * Number and size of propellant tanks–up to 16 tanks may be added
 * Electric power system capacity–expandable to 7.5 kW, with nominal consumption of 3 kW
 * Solar array configuration (if arrays are used)
 * Internal layout of the FGB
 * Volume of the FGB pressurized compartment
 * Configuration of the modules added to the FGB “aft” section


 * width="33.3%" valign="top" align="left" rowspan="2" colspan="1"|In many cases, these spacecraft performed multiple functions; for example, the Cosmos 1443 TKS served as a tug, boosting the orbit of the Salyut 7 station, delivered cargo, and was also identified as a space station module.

3.2.1 The Beginning of Soviet Multimodular Space Stations (1962-1964)
While primarily concerned with circumlunar flight, the prospectus “Complex for the Assembly of Space Vehicles in Artificial Satellite Orbit (the Soyuz)” also included reference to a space station assembled from independently-launched modules. The prospectus was the product of Special Design Bureau-1 (Russian acronym OKB-1), which today is called RKK Energia (until recently, NPO Energia). The document was approved by OKB-1’s director, Sergei Korolev, on March 10, 1962. However, OKB-1 rapidly became preoccupied with the Soyuz vehicles it was developing for the Soviet lunar program. It fell to V. N. Chelomei’s OKB-52 organization (today called NPO Mashinostro-yeniye) to start building the first Soviet space stations. On October 12, 1964, OKB- 52 began development of a space station system called Almaz (“diamond”). When approved in 1967, Almaz comprised the single-launch Almaz space station with crew capsule; the TKS (figure 3-3) which supplied the station, delivered its crews, and provided them with living quarters; and the Proton booster for launching both Almaz station and TKS.

Development of the crew capsule, sometimes called Merkur (“Mercury”) (figure 3-4) was coordinated
 * align="top" align="left" valign="top" rowspan="1" colspan="2" | [[Image:Mir-73.jpg|350px|center]] Figure 3-2. FGB. This is a simplified aft view of the propulsion/cargo module used in the TKS vehicles and as the basis for subsequent space station modules and tugs. Aft (left) details are conjectural. Solar arrays are omitted for clarity.
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 * width="33.3%" align="left" valign="top" rowspan="1" colspan="1"|by the main OKB-52 organization. OKB-52’s Branch No. 1 (ancestor of the KB Salyut organization) was charged with developing the FGB component of the TKS. The station, spacecraft, and launcher would all be built at the Krunichev Machine Building Plant. This was the same plant which built much OKB-1 hardware.


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3.2.2 TKS (1970-1978)
In February 1970, the Soviet Ministry of Machine Building ordered transfer of all completed Almaz hardware from the Chelomei bureau to the Korolev bureau. In cooperation with OKB-52 Branch No. 1, Korolev’s bureau was able to
 * width="33.3%" valign="top" align="left" rowspan="2" colspan="1"|build the first Long-Duration Orbital Station (DOS-1) within a year of the transfer. This marriage of Korolev Soyuz and Chelomei Almaz hardware was dubbed Salyut 1. It was launched on a three-stage Proton in April 1971.

Chelomei’s bureau continued work on Almaz and the TKS. In December 1976, two TKS Merkur capsules were launched atop a Proton booster under the moniker Cosmos 881-882. This, and three additional dual capsule flights, were long misinterpreted as tests of subscale lifting bodies as part of the Soviet shuttle effort. The first complete TKS (a Merkur and an FGB), Cosmos 929, reached orbit unmanned in July 1977. Its Merkur capsule was successfully recovered in August 1977, and the FGB orbited until February 1978.

About 1980, the Soviet government decided to concentrate all manned
 * align="top" valign="top" rowspan="1" colspan="2" | [[Image:Mir-75.jpg|400px|center]] Figure 3-4. Merkur capsule.
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{|cellspacing=10 cellpadding="15" width="100%" border="0" spaceflight activity at NPO Energia. One Soviet source states that Soviet Defense Minister Dmitri Ustinov “wound down” the TKS program by 1982, an assertion which seems to match the schedule of the final two TKS test flights. Cosmos 1267’s Merkur capsule reentered on May 24, 1981. Its FGB docked with the unmanned Salyut 6 station on June 19, 1981. Cosmos 1443 docked with the unmanned Salyut 7 station in March 1983. The Soviets idenified it as a cargo transport. The Salyut 7 Principal Expedition 2 crew unloaded cargo from Cosmos 1443 in July-August 1983. By this time NPO Energia’s efforts to reapply the Mashinostroyeniye TKS designs to its DOS multimodular station program were well advanced.
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3.2.3 Space Station Modules (1985-Present)
Cosmos 1686 was a transitional vehicle reflecting the decision to convert the 20-ton TKS vehicles into space station modules. It had an FGB very similar to the ones used in the Cosmos 929, Cosmos 1267, and Cosmos 1443 TKS vehicles. However, its Merkur capsule was heavily modified to house scientific instruments and remained attached to the FGB throughout its flight. Cosmos 1686 delivered 4500 kg of cargo to Salyut 7 on October 2, 1985, though this cannot be taken as evidence that it was primarily a cargo TKS, like Cosmos 1443; the Mir space station modules Kvant, Kvant 2, and Kristall all delivered cargo as well. At the time of its launch, Soviet sources stated that it had no Merkur capsule, though later Russian sources stated that it had a capsule not designed to return to Earth, which was to have been detached manually by the Chegets in January 1986. Cosmos 1686 was left attached to Salyut 7 in a long-duration test of critical systems after the last crew left the

station (1986). Cosmos 1686 underwent uncontrolled reentry with Salyut 7 in February 1991.
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The decision to adapt TKS hardware to serve the multimodular space station program affected Mir, the first multimodular station. It was originally meant to receive 7-ton modules based on the Progress design at its lateral ports. Such modules appeared often in Soviet conceptual artwork depicting multimodular stations. The first Progress-based station module was to have been the Gamma astrophysical research module. In the event, it flew as an independent unmanned satellite. Its main instrument was the Gamma-1 gamma-ray telescope. The docking unit which would have joined it to Mir was replaced in the flown version by a small compartment holding two additional telescopes.

Kvant docked at Mir’s aft port on March 31, 1987. It was delivered to Mir by a detachable FGB-based space tug. It was not itself based on the FGB or TKS. It was originally intended to dock with Salyut 7.

Kvant 2 docked with Mir in November 1989. Kvant 2 was built around an FGB. Kristall, another FGBbased module, docked with Mir in June 1990.

3.2.4 Space Tugs (1987-Present)
In 1974, on the day the Soyuz 14 crew returned from their stay on Salyut 3, Academician Boris Petrov described space tugs in an interview with the newspaper Izvestia. He stated that space tugs would be ground-controlled vehicles capable of searching for, capturing, and propelling space station modules. They would be used to bring together modules independently placed in orbit, thereby assembling large space station complexes.
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The Functional Service Module (FSM) tug which delivered the Kvant module to Mir in April 1987 was a simplified FGB. It was launched docked to the module’s aft port. The FSM detached after delivering Kvant to Mir’s aft port.

In May 1987, the first Energia heavy-lift launch vehicle carried the 80-ton Polyus space platform. A modified FGB tug was integral to Polyus, providing it with attitude control and orbit maintenance propulsion. It was also meant to complete orbital insertion for Polyus, but attitude control failure thwarted the orbital insertion maneuver. Polyus fell into the Pacific Ocean.
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3.3.1 TKS Specifications

 * Launch weight .......................................... about 19,000 kg
 * Length ....................................................... 17.51 m
 * Diameter ................................................... 4.15 m
 * Span across solar arrays ........................... 16 m
 * Number of main engines .......................... 2
 * Main engine thrust (each) ......................... 400 kg
 * Habitable volume ..................................... about 60 m$3$
 * Number of crew ........................................ 3*
 * Capsule diameter ...................................... 305 cm
 * Capsule height .......................................... 206 cm


 * * Never launched carrying a crew.

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3.3.2 TKS Notable Features

 * Launched on a three-stage Proton launch vehicle.
 * Had a unique configuration (figure 3-5). It can be thought of as two spacecraft (Merkur and FGB) joined aft to aft (figure 3-3). The Merkur capsule (figure 3-4), which up until reentry had a long, slender nose containing the capsule’s propulsion system, was attached by its aft end (heat
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 * shield) to the aft end of the FGB (figure 3-2). The forward end of the FGB was the broad, conical end with its probe docking unit. At launch the forward end of the FGB was pointed down, toward the top of the Proton booster. This put the nose of the Merkur capsule at the top.


 * Couches for three cosmonauts in the conical Merkur capsule.
 * A hatch through the capsule’s heat shield led through a tunnel into the FGB pressurized compart
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 * ment. The hatch was reached from Merkur by removing the center couch.


 * Capsule propulsion systems in module attached to the nose of the capsule. This permitted maneuvering in orbit independent of the FGB, and was also used for deorbit burns. It was discarded after completing the deorbit burn.
 * Parachute module attached to the nose of the Merkur capsule.
 * Capsule was designed to be reusable; its heat shield did not ablate during reentry.
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Figure 3-5. Cutaway of TKS vehicle. Details are conjectural. The broad black line outlines the vehicle’s pressurized compartments. A tunnel (stippled) connects the FGB and Merkur capsule.

3.4 Cosmos 1686
Salyut 7 module—Transitional vehicle (TKS to space station module) October 2, 1985-February 7, 1991 Figure 3-6. Cosmos 1686. Note the Merkur capsule (left), heavily modified to house scientific instruments.

3.4.1 Cosmos 1686 Specifications

 * Launch weight ......................................... about 20,000 kg
 * Length .................................................... 15 m
 * Span across solar arrays ......................... 16 m
 * Maximum diameter .................................. 4.15 m
 * Propellant mass at launch ........................ 3000 kg

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 * Closely resembled the TKS vehicles (figure 3-6).
 * Merkur capsule was greatly modified to carry instruments. Basically, the retrorocket and parachute packages were replaced by scientific equipment, including an infrared telescope and the Ozon spectrometer.
 * Tested systems planned for use on the Mir station base block.
 * Docked with Salyut 7 on October 2, 1985, during the long-duration stay of the cosmonauts of its fifth
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3.4.2 Cosmos 1686 Notable Features

 * Principal Expedition (the Cheget crew, which arrived on Soyuz-T 14).


 * Salyut 7/Cosmos 1686 complex (figure 3-7) massed 43 tons. Cosmos 1686 delivered 4500 kg of cargo, and nearly doubled the volume available to the Chegets. Unfortunately, they were little able to use the supplies and experimental apparatus or the room because of Vasyutin’s illness.
 * On August 19-22, 1986, ground controllers boosted the vacant Salyut 7-Cosmos 1686 complex to a 474 km by 492 km orbit using engines on Cosmos 1686.
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 * This reduced the propellant supply of the complex to 70 kg (about 500 kg were required for controlled deorbit). In addition, Cosmos 1686 and Salyut 7 each suffered major systems breakdowns soon after they were abandoned, making the complex impossible to control.

Figure 3-7. Cosmos 1686 and Salyut 7.
 * All previous space stations over which the Soviets maintained control were intentionally deorbited after their last cosmonaut crew departed. The Soviets estimated that the reboost gave the complex an 8-yr lifetime in orbit. They considered recovering the station using the Buran shuttle.
 * Cosmos 1686 underwent uncontrolled reentry with Salyut 7 on February 11, 1991.
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3.5 Kvant
Mir module—astrophysics and attitude control March 31, 1987-present
 * width="66.6%" align="left" rowspan="1" colspan="1"| [[image:Mir-79.png|350px]] Figure 3-8. Kvant module.
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3.5.1 Kvant Specifications

 * Total launch weight .................................. 20,600 kg
 * Mir module weight ................................... 11,000 kg
 * Functional Service Module (FSM)
 * weight ..................................................... 9,600 kg
 * Length ..................................................... 5.8 m
 * Maximum diameter ................................... 4.15 m
 * Habitable volume ...................................... 40 m3
 * Anticipated lifetime at launch ..................... 5 yr

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3.5.2 Kvant Notable Features

 * Kvant (figure 3-8) was originally designed for use with Salyut 7, but launch was delayed past the endurance of that station.
 * Only space station module to dock at the rear port of a Salyuttype space station.
 * Two pressurized living and working compartments and an unpressurized (20 cu/m) experiment compartment.
 * Absence of an integral propulsion system. Delivered to Mir by FSM tug (figure 3-14).
 * Absence of a power generation system. Kvant relies on the Mir
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 * base block’s solar arrays for electricity. The Kristall module arrays are scheduled to be moved to Kvant in 1994, prior to the docking by Space Shuttle Atlantis with Mir in 1995. EVAs in 1991, 1993, and 1994, prepared the way for the transfer of the Kristall solar arrays to Kvant.


 * Plumbing for transferring fuel from a Progress M spacecraft arriving at Kvant’s rear port to propellant tanks for attitude thrusters in the Mir base block. Plumbing also transfers other fluids.
 * Rear port features Igla and Kurs rendezvous and docking systems. Front port features Igla only; it was used for initial docking with
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 * the rear port of the Mir base block. After docking in 1987, the front port Kvant antenna was folded down, its work done.


 * Module blocks the main engines at the rear of the Mir base block. Since Kvant docked, all orbital maintenance maneuvers have been carried out by docked spacecraft.
 * Six control moment gyros (gyrodynes), with a total mass of 990 kg, which permit extremely accurate pointing of the complex (necessary for astronomical observations). The gyrodynes reduce the amount of attitude control propellant needed by the Mir base block’s control thrusters. They do, however, use a great
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3.6 Kvant 2
Mir module—augmentation of base block’s capabilities, EVA airlock November 26, 1989–present

3.6.1 Kvant 2 Specifications

 * Launch weight ........................................... 19,565 kg
 * Length ...................................................... 13.73 m
 * Diameter ................................................... 4.35 m
 * Habitable volume ....................................... 61.3 m$2$
 * Span across solar arrays ............................ 24 m
 * Solar array capacity .................................. ~7 kW
 * Anticipated lifetime at launch ..................... 3 yr

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3.6.2 Kvant 2 Notable Features

 * Referred to as D-module (Dushnashcheniye module) or augmentation module prior to launch (figure 3-9).
 * First module to be put in place at one of the Mir base block’s four lateral ports.
 * Three compartments, including specialized EVA airlock compartment, central instrument and cargo compartment, and instrument and experiment compartment.
 * Central instrument and cargo compartment can be sealed and depressurized, serving as either an airlock compartment extension or a backup to the EVA airlock compartment.
 * Solar arrays of a design similar to those on the Mir base block.
 * 1-m EVA hatch, first Soviet spacecraft hatch designed to open outward.
 * Kurs rendezvous and docking system for docking with Mir’s front port.
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 * Delivered the Soviet “flying armchair” manned maneuvering unit (Russian acronym YMK) and advanced new Orlan-DMA EVA suits.
 * Lyappa arm (figure 3-10) attached to a fixture in the Mir base block’s multiport docking node and pivoted Kvant 2 from the front longitudinal port to its assigned lateral port (figure 3-11). Kristall, Priroda, and Spektr also carry the Lyappa arm.
 * Delivered the Salyut 5B computer, which was designed to take over from the Argon 16B computer in the Mir base block. Salyut 5B is faster and has more memory than the older computer, and thus is more capable of managing the expanding Mir complex.
 * System for regenerating water from urine. The water produced is electrolyzed to produce oxygen in an Elektron system similar to the one on Kvant.
 * Shower cabinet for personal hygiene, a metal compartment through which warm air circulates. Water is supplied through a
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 * sprayer. A “gas-liquid separator” siphons used shower water to a regenerator, which processes the water for reuse (the latter is part of the dehumidifier system which recycles water from the air). In practice this system has not worked as well as hoped. Water adheres to the user and the sides of the cabinet, making drying and cleanup difficult.

Figure 3-9. Kvant 2 module. Kvant 2 houses an EVA airlock (hatch visible at left).
 * Rodnik (“spring”) water system launched with 300 liters/420 kg of water in external tanks.
 * Launched with other cargo, including 600 kg of propellant; 285 kg of food; 28 kg of air; and 200 kg of experimental equipment. *Scientific equipment includes the Priroda 5 high-resolution camera, MKF-6MA multispectral Earth resources camera, MKS-M2 optical spectrometer on the ASPG-M platform, ITS-7D infrared spectrometer on the ASPG-M platform, ARIS X-ray sensor on the ASPG-M platform, Inkubator-2 unit for hatching and raising Japanese quail, VEP-3 and VEP-4 panels for monitoring
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Figure 3-11. Repositioning Kvant module using Lyappa arm.

Figure 3-12. Kristall module. Kristall joined Mir in 1990. It carries two APAS-89 docking units (left).

3.7 Kristall
Mir module—Shuttle docking, materials processing, and Earth observation May 31, 1990–present

3.7.1 Kristall Specifications

 * Launch weight .......................................... 19,640 kg
 * Length ..................................................... 13.73 m
 * Diameter .................................................. 4.35 m
 * Habitable volume ....................................... 60.8 m$3$
 * Span across solar arrays ........................... about 36 m (maximum)

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3.7.2 Kristall Notable Features

 * Kristall (figure 3-12) referred to as the T-module (Teknologia module) or Kvant 3 prior to launch.
 * At aft end is a node with two ports, each fitted with APAS-89 androgynous docking apparatus (figure 3-13). APAS-89 is similar to the APAS-75 docking unit (see section 1.9.2) jointly developed by the U.S. and Soviet Union for ASTP (1975). The chief difference is APAS-89’s inward-facing spade-shaped guides. The guides were turned inward to be placed outside the pressurized tunnel
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 * linking the two spacecraft electrical and fluid connections running through the docking collar. Conversely, this placed mechanical systems located outside the collar on the APAS-75 inside the APAS-89 collar. APAS-89 was tested in space by the Soyuz-TM 16 spacecraft, which docked at the lateral APAS-89 Kristall port in 1993. Originally built for a Soyuz-class vehicle as part of the Mir-2 space station program, a modified version was prepared for Buran shuttle/Mir dockings, but never used in that capacity. It is expected to be used in further modified form by U.S. Shuttle Orbiters beginning in 1995. Atlantis will use one of these to dock with Mir for the first time on the STS-71 mission in 1995. Seven U.S. Shuttle visits to this port are planned through 1997.


 * Materials processing furnaces (Krater 5, Optizon 1, Zona 2, and Zona 3) and biotechnology experiment apparatus (Ainur electrophoresis unit) weighing 500 kg, which are capable of generating 100 kg of material per year for industrial use on Earth.
 * Priroda 5 Earth resources cameras in the docking node.
 * Svet “hothouse” for growing radishes and leaf lettuce.
 * Folding “collapsible” solar arrays weighing 500 kg. The arrays are designed to be transferred to the Kvant module, where they will be shaded less frequently.
 * Six gyrodynes for attitude control.
 * Glazar 2 ultraviolet telescope, augmenting the Glazar ultraviolet telescope on Kvant (together the two instruments swept areas of the sky 90° apart); Mariya magnetic spectrometer; Marina gamma ray telescope; Buket gamma spectrometer; and Granat astrophysical spectrometer.
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3.8.1 Kvant Functional Service Module (1987-1988)
Service Module (1987-1988) Probably the “purest” space tug of the Soviet/Russian program was the Kvant Functional Service Module (FSM) (figure 3-14). The FSM was a stripped-down FGB. Presumably it was thus launched “tail-up” like the TKS spacecraft, an idea supported by the streamlined structure covering the FSM’s aft, where the Merkur capsule would be located on a TKS. It was launched docked with Kvant’s aft port on March 31, 1987. This would have placed the Kvant module with the probe docking unit meant to attach it to Mir pointed downwards at launch, against the top of the Proton booster. Kornilov’s article about the Polyus spacecraft (see below) contains information on Polyus’ design which adds credence to this suggestion. Together the module and FSM formed an integrated spacecraft, with navigation data from antennas at Kvant’s front fed to the attitude control system in the FSM. The first attempt to dock Kvant failed; the second was successful, but only after an EVA to remove a foreign object from the docking mechanism. The Kvant FSM undocked from the Kvant aft port on April 13, and boosted to a storage orbit with a mean altitude only 41 km higher than that of Mir. The FSM underwent uncontrolled reentry on August 25, 1988.
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 * width="33.3%" align="left" valign="top" rowspan="1" colspan="1"| [[image:Mir-85.png|225px]] Figure 3-15. Polyus cutaway. Displays the FGB-based service/propulsion module. Note that, like other FGBbased vehicles, it launched aft end up. This places Polyus’ front end at the bottom. The streamlined projections on Polyus’ sides were dispensers for experimental tracking targets.


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3.8.2 Polyus Service Module (1987)
In July-August 1992, Yu. P. Kornilov, chief lead designer at Salyut Design Bureau, described in an article the Polyus spacecraft (figure 3-15). Polyus (“pole of the Earth”) was the payload of the first Energia rocket flight (May 15, 1987) (figure 3-16). In July 1985, the Ministry of General Machine Building ordered the Salyut Design Bureau to create a new spacecraft for the first Energia test flight, then scheduled for autumn 1986. The short lead time forced novel approaches to management and construction. Existing hardware, including systems developed for the Buran shuttle program, was used whenever possible. The final configuration had the following attributes:
 * Length: 37 m.
 * Diameter: 4.1 m.
 * Approximate weight: 80,000 kg.
 * Two modules: a small operations/service module and a large special-purpose module.
 * Nose fairing made of “carbonfilled plastic.” This was the first nonmetallic fairing used in the Soviet space program.
 * Used Buran ground support equipment; also originally designed for Buran were the supports linking Polyus to Energia and the system for separating Polyus from Energia.

The new spacecraft’s operations/service module was based on an FGB with the following attributes:


 * Contained all Polyus attitude control and internal systems control equipment, the telemetry system, the power supply system (twin solar arrays, as on the TKS vehicle), the fairing jettison system, antennas, and the scientific experiment control systems.
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 * Polyus electronic systems unable to withstand hard vacuum were placed in the FGB’s pressurized compartment.
 * Propulsion system had 4 sustainer engines, 20 attitude control thrusters, and 16 vernier engines.
 * Approximate weight: 20,000 kg.
 * To meet deadline imposed on Polyus development, the FGB used was one which had exceeded its planned “shelf-life.”

According to Kornilov, Polyus had the following mission objectives:
 * Test feasibility of launching heavy (100-ton) side-mounted (asymmetrically positioned) payloads on the Energia rocket such as would be used in planned advanced space station programs (primary objective).
 * Test future systems, including a docking system. The docking approach radio and optical systems would be tested using reflectors—small inflatable spheres and angled reflectors released from “side units” located on either side of the front of the Polyus spacecraft. The streamlined “side units” were sometimes mistaken for orbit insertion engines in early Western analyses.
 * Study interaction of gas and plasma produced by Polyus with natural ionospheric plasma. Polyus contained 420 kg of xenon and krypton in 42 tanks, each with a capacity of 36 liters. Polyus was launched backwards, with its engines pointing upward and its front end pointed down, toward the Energia launch pad’s flame pit. This configuration was dictated by the FGB heritage of its aft-mounted operations/service module. The FGB-based module was launched with its broad front end down, and its engines pointed up, just as it would have been had it been launched atop a Proton. When the FGB was part
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