MIR OVERVIEW the Russian Space Station Mir, Which Has Become An

Home , Kristall, Mir Core Module, Orbital module, Spektr

MIR OVERVIEW

The Russian space station Mir, which has become an important part of the U.S.-led effort to build the International Space Station, is itself the latest stage in the evolution of Russia’s manned space program.

Since 1971, Russia has been pushing back the limits on human presence in space, first with the Salyut series of space stations and now Mir. The current station is the result of numerous improvements the Russians made in the design of the Salyut spacecraft, but it re- tains the basic modular approach—the joining of various space vehicles to form a station—that has been the hallmark of the Rus- sian manned space program.

Mir is a third-generation space station. Its design is based on the modules of the second Salyut station. Mir (Russian for “peace,” “commune,” and “world”) is actually a complex of various modules: the core module, Kvant-1, Kvant-2, Kristall, Spektr, and Priroda. 27

MIR MODULES

The core module was the first element of the Mir complex to be placed in orbit. It was launched on a Proton rocket in February 1986, several months before the last Salyut station was removed from service. The orbiting station has been manned almost continuously since then. Atlantis approaches Mir during STS-74 mission (November 1995) The core module is the control center for the entire space station and also contains work and living areas. Two concentric cylinders, 43 feet long, make up this major habitable volume. The working area houses not only the control center but also a pilot’s the spacecraft that transport crew members and supplies to the sta- station and medical monitoring equipment. The living area has indi- tion and back to Earth. The docking module has a transfer vidual crew cabins, a galley, and a personal hygiene compartment compartment that allows the crew to travel between the Mir mod- complete with toilet, sink, and shower. ules and unload incoming supplies and equipment.

A docking module attached to the forward end of the core mod- Two Kvant (pronounced kwahnt) spacecraft serve as Mir re- ule has four radial ports for additional modules and an axial port for search modules. (Kvant means “quantum” in Russian.) Mir Core Module Length 43.3 ft Maximum Diameter 13.7 ft Habitable Volume 3,000 ft3 Priroda Weight at Launch 45,444 lb Launch Weight 43,431 lb Launch Vehicle Proton (Three-Stage) Length 43 ft Orbital Inclination 51.6 deg Diameter 14.35 ft Number of Solar Arrays 2 (Third Added During EVA) Habitable Volume 2,337 ft3 Span Across Solar Arrays 98 ft Anticipated Lifetime Area of Solar Arrays 844 ft2 (1,088 ft2 With Third Array) at Launch 3 yr Electricity Available 9-10 kW at 28.6 V Resupply Carriers Progress, Progress M Number of Docking/Berthing Ports 2 Docking, 4 Berthing Number of Main Engines 2 Main Engine Thrust (Each) 666 lb Kvant-1 Total Launch Weight 45,777 lb Spektr Mir Module Weight 24,444 lb Launch Weight 43,299 lb Functional Service Module Weight 21,333 lb Length 43 ft Length 19.14 ft Diameter 14.35 ft Maximum Diameter 13.7 ft Habitable Volume 2,186 ft3 28 Habitable Volume 1,333 ft3 Anticipated Lifetime at Launch 5 yr

Kvant-2 Launch Weight 43,477 lb Kristall Length 56.3 ft Launch Weight 4,362 lb Diameter 14.35 ft Length 56.3 ft Habitable Volume 2,043 ft3 Diameter 14.35 ft Span Across Solar Arrays 792 ft Habitable Volume 2,147 ft3 Solar Array Capacity ~7 kW Span Across Solar Arrays 118 ft Anticipated Lifetime at Launch 3 yr Mir Space Station MTD 950109-5097

Mir Space Station Kvant-1 is equipped with six gyrodynes, which provide ex- tremely accurate pointing of the space station and significantly reduce the amount of fuel used for attitude control. In 1992, Russian space- walking cosmonauts placed a thruster on top of a 48-foot-tall girder they erected and attached to Kvant-1 in 1991 to improve Mir’s attitude control.

For performing astronomical observations, the astrophysics module has a Roentgen X-ray telescope suite of four instruments developed by Britain, the Netherlands, the European Space Agency, and Russia, and an ultraviolet telescope. The telescopes cannot be aimed without orienting the entire Mir complex. The science equipment also includes an electrophoresis unit.

Kvant-2 docked with Mir in November 1989. The 40-foot-long MTD 950504-5181 module is equipped with an airlock that permits cosmonauts to leave Mir Core Module the module for spacewalks, a central instrument and cargo compartment, and an instrument and experiment compartment. The central Kvant-1, the astrophysics module, is equipped for celestial ob- 29 servations and some biotechnology experiments. The 19-foot-long module, which is connected to the aft end of the core module, houses a laboratory with separate areas for instrumentation and living.

Kvant-1 docked with Mir in April 1987. Because it does not have its own propulsion system, the astrophysics module had to be delivered to Mir by a Russian space tug. It began its astronomical observations in June 1987 by studying Supernova 1987a in the Large Magellanic Cloud.

Plumbing in Kvant-1 allows fuel and other fluids to be transferred to the core module from resupply craft that dock at Kvant-1’s aft port. The fuel is used by attitude thrusters in the core module.

Kvant-1, which was originally designed to be part of the Salyut space station, is the only module that docks at the core module’s rear port. Because Kvant-1 blocks the main thrusters on the aft end of the MTD 950504-5184 core module, docked spacecraft have had to perform the station’s orbital maintenance maneuvers. Kvant Astrophysics Module shower is delivered, the crew will use wet wipes for personal hygiene.

Kvant-2 was the first module equipped with the Lyappa arm, which is used to move the modules after they dock with Mir. The arm was attached to a fixture on the docking node and transferred Kvant-2 from the front axial port to one of the radial ports. The Kristall, Spektr, and Priroda modules also have a Lyappa arm.

Opposite Kvant-2 is the Kristall technology module, which ar- MTD 950504-5183 rived in June 1990. Kristall (which means “crystal” in Russian) is used to develop zero-g material and biological production techniques. Kvant-2 Module The 39-foot-long module contains an instrument/cargo compartment equipped with materials processing furnaces, biotechnology experiment apparatus, a hothouse for growing radishes and lettuce, an compartment can be sealed and used as an extension of or backup to ultraviolet telescope, an Earth resources camera, and several spec- the airlock. trometers. Following STS-71, Kristall was positioned at a radial port between Spektr and Kvant-2. This module supports Earth observation and biological research, 30 including experiments involving specimens that must be exposed to The Kristall module has two docking ports with androgynous the space environment outside the module. The module’s comple- docking mechanisms. The mechanisms are similar to the docking ment of scientific equipment includes a high-resolution camera, a apparatus built by the U.S. and Soviet Union for the Apollo-Soyuz multispectral Earth resources camera, an optical spectrometer, an linkup in 1975. They were designed for docking the Russian Buran infrared spectrometer, an incubator for hatching and raising Japa- but will be used by space shuttle orbiters instead. The Buran, or nese quail, a fluid flow experiment, and panels for monitoring “snow storm,” was the Russian equivalent of the U.S. shuttle orbit- conditions outside the space station. ers.

Kvant-2 also delivered a new, faster computer with more memory capability to manage the expanding Mir space station and brought the Russian manned maneuvering unit and new space suits for use on spacewalks. The space station’s attitude control capability was augmented by Kvant-2’s six gyrodynes and 32 thrusters.

Kvant-2 is equipped with a system that converts urine into water, which is then used to produce oxygen. It also has a shower that reclaims and processes the water for reuse. In April 1995, the Mir MTD 950504-5182 crew removed the shower unit and installed a gyrodyne that is used for attitude control when the shuttle docks with Mir. Until a new Kristall Module The 30-foot-long Spektr (“spectrum”) module, which was launched May 1995, adds an Earth-monitoring capability to Mir. It can measure sources of radiation on the Earth, such as active volca- noes, gas torches, and forest fires, and investigate environmental pollution. Investigators will also be able to study the effects of changes in the sun’s activity.

Spektr carried more than 1,600 pounds of scientific equipment, two pairs of solar arrays to boost power to the aging Russian station, and a new robotic arm to shuffle the massive Mir modules around in preparation for nine dockings with the shuttle orbiter. Spektr’s solar arrays are now almost fully deployed.

The newest addition to the Mir complex is the Priroda module, added in April 1996. Priroda, which means “nature,” supports experiments dealing with remote sensing and observation of the Earth. Cosmonauts and astronauts will conduct studies of the Earth’s at- mosphere and surface and will continue experiments begun earlier MTD 960827-5737 on the space station. 31 Priroda Module

DOCKING AND BERTHING MECHANISMS

Two kinds of mechanisms enable spacecraft to dock with Mir.

Probe-and-drogue devices are used to mate the Soyuz and Progress spacecraft with Mir in addition to connecting Kvant-1, Kvant-2, Kristall, and Priroda to the berthing ports on the Mir core module. The probing rod, located on the active mating element (spacecraft), enters the receiving cone of the passive, or drogue, element (the station). After the capture latch at the end of the probe mates with a socket at the end of the drogue cone, an electric drive retracts the probe and pulls the two parts of the docking mechanism together until a mechanical stop is reached. Axial and late motion is damped by electromechanical devices and shock absorbers. Then MTD 960827-5750 active hooks secure the two assemblies around the docking interface seal. Spektr Module Passive Assembly Station Side

Receiving Cone

Capture Latch

Pilot Charles Precourt (STS-71) points out an element of the Russian-built Active Assembly androgynous peripheral assembly, which sits on top of the orbiter docking Soyuz Side 32 system, to commander Robert "Hoot" Gibson.

MTD 950504-5179 The second mating device is the androgynous docking mechanism, which is designed to mate with a like device on the Buran Probe-and-Drogue Docking Mechanism orbiter and the space shuttle orbiter. The mechanism consists of a three-petal androgynous capture ring mounted on six interconnected axis to provide clearance for each shuttle docking. The longitudinal ball-screw shock absorbers. This docking mechanism was used for axis is normally used by Progress resupply modules and Soyuz space- the first time to mate the orbiter Atlantis with Mir during STS-71 craft. Moreover, it was inconvenient to move Kristall from port to and is installed on both ends of the docking module delivered to Mir port in preparation for each shuttle docking. on STS-74. The new DM allows clearance for the shuttle to dock with Kristall MIR DOCKING MODULE at the radial axis of Mir. Kristall will not be moved from that loca- tion and all future shuttle dockings will use the DM, which may also A Russian-built docking module (DM) was delivered by Atlantis be used for future Soyuz dockings. during STS-74 and attached to the Kristall module of the Mir space station so that the shuttle can dock with the Kristall module at the Docking Module Structure Mir radial port on future missions. The basic elements of the DM are the pressure-sealed body, Without the DM, Kristall had to be moved to Mir’s longitudinal androgynous peripheral docking system (APDS), trusses for pay- Fuse Panel Interior Light

APAS Control Panel TCS Control Panel Hatch Dust Filter

APAS-1 Connector Window Feed- Fan Through

1 1 130° Utility Outlet 3

Centerline Camera 33 3 (On-Orbit Only) 2 [TB KAMEPA] Camera/Fan

Window Pressure Equalization Pressure Equalization Valve Valve NPRVs Manual Circuit APAS Power APAS Fuse Manual Valve Breaker Panel Panel Panel TCS Air Circulation Fan TCS Overboard Vent TCS Heater Pump/Fan Thermal Control System (TCS) Control Unit Controller Control Unit MTD 951103-5482

Docking Module Interior (Starboard) APAS Control Power Circuit Select Boxes Switching Power Distribution Unit Unit Interior Light

Lab Lighting Panel Dust Filter Handrail APAS-2

Connector Feed-Through Spare Air Circulation

NPRV Utility Matrix Primary Window Fan Outlet Air Stowage Bracket Circulation Switching Patch Fan Units Panels PEV Drive Control Units MTD 951103-5481

Docking Module Interior (Port Side) Cooperative Kristall module. Several Russian vehicles also use this mechanism Solar Array to dock with Kristall and other Mir modules. The APDS design is APAS-2 Russian and was used before as part of the Apollo-Soyuz Test Pro- gram in 1975. The same mechanism is planned for the ISSA. As the Railing Reusable Solar Array name implies, the two halves of each docking mechanism interface are androgynous, meaning there is no distinction between them and any half can physically mate with any other half. Payload Disconnect Assembly The DM is constructed of aluminum alloy covered by screen vacuum thermal insulation (SVTI) and a micrometeoroid shield. Two containers on both sides of the top of the module transported new solar arrays to Mir. The two solar arrays are different types. One, called the cooperative solar array (CSA), was built as a cooperative Grapple effort by NASA and Russia; the other is a Russian solar array (RSA). Fixture The CSA, which uses Russian structures and NASA photovoltaic modules, was designed during Phase 1 operations of the Interna- Trunnion tional Space Station program. The array is expected to provide more power and longer life than existing arrays and helps power U.S. ex- Scuff Plate periments aboard Mir. The solar arrays were attached to Mir during 35 External Camera a spacewalk by cosmonauts after STS-74. APAS-1 and Light MTD 951103-5461 Interior Arrangement

Docking Module The DM’s center aisle is flanked by port and starboard avionics bays that run the length of the cylindrical midsection of the module. load bay mounting, assemblies for attaching the solar array cargo, a The bays are formed by an aluminum alloy frame mounted to bulk- grappling fixture, outboard television cameras and docking aids, an heads that separate the hemispherical ends from the cylindrical electrical umbilical, extravehicular activity (EVA) handrails, and midsection. The front of each bay is enclosed by lightweight lami- internal support systems mounted on racks in two avionics bays. nated aluminum closeout panels Velcroed into position and pinned at the corners to support launch loads. The ceiling is formed by the The DM is 15.4 feet long from tip to tip of the identical APDSs curved exterior hull. The floor is formed by aluminum panels that on either end. For identification purposes, APDS-1 is the system allow cabling to pass between the avionics bays, protect piping, and attached to Kristall and APDS-2 attaches to the shuttle. The DM support the deliverable cargo pallet. diameter is 7.2 feet, and the module weighs approximately 9,011 pounds. The DM avionics are mounted on aluminum racks welded di- rectly to the DM hull in the standoff spaces behind the avionics bay The APDS mechanism is universal. It is used to attach the DM closeout panels. These closeout panels channel forced air driven by to the orbiter docking system (ODS) and to dock the DM with the fans mounted in each bay over the avionics for cooling. Air filters are located at the APDS-1 ends of the module, where air is drawn surizes the Kristall vestibule with Mir air. (Kristall vestibule pres- into the avionics bay channels. Cooling air is exhausted through the sure telemetry is not available to the shuttle or Mission Control in fan at the opposite end of the bay. The avionics bays contain all of Houston.) The shuttle crew equalizes pressure between the DM and the DM control systems. the Kristall vestibule with the DM/Kristall system before opening the DM APDS-1 hatch. The Mir crew equalizes pressure across the Two ceiling-mounted fluorescent lights, one at each end on op- Kristall hatch by using the Kristall vestibule equalization valve be- posite sides, provide interior illumination. Circular handrails are fore the Kristall hatch is opened. All intermediate volumes are mounted around the periphery of the hatches at each end of the mod- leak-checked before a hatch is opened. ule. A longitudinal handrail runs the length of the port-side avionics bay approximately midway between the ceiling and floor. A small There are two Russian-built hatches on the DM, one at each handrail is mounted vertically along the starboard air filter cover at end. They are similar to the Kristall hatch and are physically part of the aisle edge of the bay sidewall. the APDS mechanism housing that is welded to the DM shell. The hatches are designed to open inward and to be secured in the open The closeout panels enclosing the avionics bays are sized and position by lock-back mechanisms on the hatch hinge. To open or numbered to allow access to specific equipment mounted in the bay. close a hatch requires a special hatch tool. The hatch actuator nut All panels are completely covered with a woven material similar to resides on a hatch actuator plate (HAP), labeled in Russian and trans- Velcro pile. lated into English. Telemetry is available to indicate when the DM APDS-2 hatch is open, and the standard switch panel shows when Environmental Control the DM APDS-1 hatch is open. Each hatch has three microswitches 36 to sense hatch closure. Only one microswitch needs to be released The DM environmental controls consist of pressure and ther- (closed) to generate a valid hatch-open signal. The maximum differ- mal systems. The first includes all pressure relief and air ential pressure against which a DM hatch can be opened is 10 to 15 pressurization systems. The Russian system definition of thermal mmHg. control includes the DM fluid loop and related equipment such as pumps and fans. Air Revitalization. To maintain a shirtsleeve environment for the crew, the DM depends on its controlling vehicle for air revital- Pressure. The entire DM maintains a pressurized environment ization, such as carbon dioxide and humidity removal. DM internal for crew members. Pressure is held by the exterior shell and hatch fans circulate ambient DM air while air ducts from the controlling seals at both ends of the module. A system of pressure valves allows vehicle into the DM support atmospheric conditioning. When the the DM to be pressurized before launch and to equalize pressure shuttle controls the DM, shuttle systems support the DM atmospheric before the shuttle-to-DM or Kristall-to-DM hatches are opened. A parameters. Once Mir controls the DM, the required parameters are system of shuttle- and Mir-based pressure valves is also needed to provided by Mir systems. pressurize and depressurize the vestibule formed between the DM hatch and the mating vehicle hatch when the docking mechanisms Thermal Control. The temperature of the DM is controlled by mate. The DM is pressurized to 920 mmHg (1.2 standard atmo- passive thermal blankets, a fluid cooling loop, fans for avionics equip- spheres) at 20°C before launch. ment, and the APDS window fan. The APDS window fan mounts near the bracket that holds an interior centerline camera and pre- After the shuttle has docked with Kristall/Mir, the Mir crew pres- vents the window from fogging during docking operations. Rendezvous/Docking Aids

The trajectory control sensor (TCS) is a JSC-designed laser sensor package that provides relative trajectory data about a target vehicle operating in close proximity (less than 1,500 meters) to the orbiter. It provides range, range rate, bearing, bearing rate, attitude, and attitude rates for target vehicles by using special retroreflectors.

The DM has four JSC retroreflectors that are used in shuttle dockings. The hemispherical retroreflectors are mounted on the side of the DM and on the back of the grapple fixture.

Retroreflectors on the Kristall module were designed and built in Russia to assist the Soyuz-Mir rendezvous and docking. Tests at JSC indicate that these retroreflectors are compatible with the TCS. MTD 950504-5180 VISITING SPACECRAFT Soyuz-TM Spacecraft The Soyuz-TM, which transports crews and cargo to and from 37 Mir, docks at the axial port on the transfer compartment of the core module. The Soyuz has three components. The descent module, where the crew stays during launch, orbital maneuvers, rendezvous, docking, and descent, accommodates three suited crew members. It contains the main systems control station for the spacecraft. The orbital module, which contains life support, rendezvous, and docking systems, is a crew habitat during nondynamic flight phases. The instrument assembly module, a cylindrical shell, contains the orbital flight systems.

Usually, the Soyuz-TM is launched from the Baikonur complex and takes two days to reach Mir and complete docking operations. Only the Soyuz maneuvers during docking operations; Mir remains passive. As a precaution in preparation for docking, the crew members aboard Mir put on their space suits and wait in the resident Soyuz, which has been docked at the station throughout their stay. The arriving Soyuz always docks at one of Mir’s axial ports. MTD 950504-5180

Progress-M Logistics Resupply Spacecraft Since the Soyuz-TM has a limited life in space, this rotation of Priroda Base vehicles guarantees that the Mir crew will always have a way back Module to Earth.

Progress-M The unmanned Progress-M, with a cargo capacity of about 5,300 Spektr pounds, transports cargo and new supplies to Mir and returns waste and scientific data to Earth. Docked to Mir or flying freely, Progress can also be used to conduct scientific experiments. Soyuz-TM MISSION CONTROL

Kvant-2 Kvant At Russia’s Kaliningrad complex, there are three control rooms, each dedicated to a specific Russian space program: Soyuz-TM, Kristall Buran, and Mir. The Mir and Soyuz control rooms are similar to the Docking U.S. Mission Control Center, even to the large map of the world in Module the front of the rooms. Since each Mir module can produce its own telemetry stream, the modules are sometimes considered separate vehicles. The console controllers can display data from as many as three vehicles simultaneously. 38

Orbiter Docking Like the U.S. Mission Control staff, Russian flight control per- System sonnel are grouped in teams. Four teams of controllers work on each Soyuz flight and five teams work on each Mir mission. After work- Shuttle ing a 24-hour shift, one Soyuz team takes three days off while the MTD 960827-5719 next team takes over; the Mir teams rotate off for four days. Most of Mated Configuration, STS-79 the console positions are vacant most of the time because the period of communication coverage is so brief. When docking is completed and the hatches are opened, both crews take off their space suits and begin the exchange of informa- Each day, the MCC team in Moscow uplinks a flight plan to the tion and tasks referred to as “hand-over” activities. At the end of the Mir crew, describing a one-day schedule of activities to be performed hand-over period, all crew members again don their space suits. The five days later. Thus, the team that developed the agenda will be on departing crew gets into the resident Soyuz, which has been docked duty when the plans are being carried out. The Mir crew works at the station the longest, and the new crew waits in the Soyuz that from 8 a.m. to 11 p.m. five days a week. All crew members must has just arrived until the resident Soyuz undocks and starts back to exercise for two hours each day, including days off. During signal Earth. Once the resident Soyuz has left, the crew moves the new acquisition periods, the Mir crew can have voice and two-way video Soyuz to a radial port so that the axial port is free to dock the next communication with the ground. spacecraft.

Source: Some information used in this article came from Cosmonautics: A Colorful History. Wayne R. Matson editor. Cosmos Books: Washington, D.C.