The Mir Space Station
For 24 years Soviet/Russian space stations have demonstrated the technology required to maintain a human presence in Earth orbit and have proven the utility of manned experiments across a wide spectrum of scientific disciplines. Since the launch of Salyut 1 in 1971, seven Soviet space stations have supported more than 11,000 man-days (30 man-years) of on-orbit experience. (Three other space stations were lost during or shortly after launch during 1972-1973 and were never occupied.) The current Mir Space Station represents the culmination of this technological evolution and embodies many of the operational concepts adopted by the ISS. The evolution of Soviet space stations is shown in Figure 8.
NOTE: FIGURE 8 TO BE INSERTED HERE
Figure 8 The evolution of Soviet space stations.
Source: Johnson (1994). Reprinted by permission from Teledyne Brown Engineering.
Assembly of the Mir Space Station began in February 1986 with the launch of the first element: the Mir core module. Originally anticipated for a seven-year life span, the Mir orbital complex was to consist of six permanent modules serviced by manned and unmanned logistics spacecraft and to be completed by 1990. However, after seven years in orbit only four of the six permanent modules (Mir in 1986, Kvant 1 in 1987, Kvant 2 in 1989, and Kristall in 1990) with a total mass of more than 70 metric tons had been launched. The launches of the remaining two modules were repeatedly delayed. As part of Phase 1 of the ISS program, the precursor phase of international cooperation using the Mir and the Space Shuttle prior to beginning the assembly of ISS, additional modules are being docked to Mir. The Spektr Module was docked in June 1995, and the final Mir module, Priroda, is scheduled for docking in December 1995. Both modules are equipped with U.S. research payloads and equipment as well as Russian equipment.
During its first nine years in orbit, the Mir Space Station hosted 17 main expeditions, which accumulated nearly 19 person-years of activity with crews representing nine countries or organizations (Afghanistan, Austria, Bulgaria, ESA, France, Germany, Japan, Syria, and the United Kingdom), in addition to the many republics of the former USSR and the now Commonwealth of Independent States. A record 14-month mission was completed in March 1995 by Dr. Valeri Polyakov, who spent a total of 22 months on the orbital complex. The facility has been permanently manned since September 1989, and by April 1995, had received 71 different spacecraft of eight types. As shown in Table 2, an average of 7-8 missions have been flown annually from 1986 to 1994 without a launch failure (67 Soyuz and 4 Proton launch vehicles in all); all spacecraft have successfully rendezvoused and docked with the complex. More than 90 successful dockings have been accomplished (including those dockings associated with repositioning spacecraft for logistical reasons).
TABLE 2 Launch and Resupply History of Mir, 1986-1994 YEAR Modules Soyuz Soyuz-TM Progress Progress-M 1986 Mir 1 1 2 0 1987 Kvant 1 0 3 7 0 1988 0 3 6 0 1989 Kvant 2 0 1 2 2 1990 Kristall 0 3 1 3 1991 0 2 0 5 1992 0 2 0 5 1993 0 2 0 5 1994 0 3 0 5 TOTAL 4 1 20 18 25
To support the significant logistical requirements of the Mir Space Station (about 10-12 metric tons per year), the previously proven Soyuz-T manned transport and the Progress automated cargo ferry were enhanced to create the current Soyuz-TM and Progress-M variants. The Soyuz-TM spacecraft debuted in 1986 and had carried 20 crews of 2-3 people to the Mir Space Station by the spring of 1995. Capable of independent flight for several days or being docked with Mir for more than six months, the 7.1-metric-ton Soyuz-TM design will be modified to serve as an ISS crew-return vehicle. The Soyuz-TM is rated as able to return up to three cosmonauts to an Earth site on land or at sea.
The 7.3-metric-ton Progress-M freighter can resupply the Mir Space Station with more than 2.5 metric tons of material, including food, air, water, propellants, clothing, equipment, replacement parts, and a wide assortment of other cargo. More than 70 Progress (1978-1990) and Progress-M (1989-present) vehicles have been launched, and each one has successfully docked with its intended space station (Mir or one of its Salyut predecessors). Most dockings are automated (a crew need not even be on board the space station), but a cosmonaut can take control and perform the operation manually, if necessary. In 1990 the Raduga reentry capsule was introduced, permitting suitably equipped Progress-M spacecraft with the ability of returning up to 150 kg of material to Earth. Progress-class spacecraft have also been used to perform special scientific experiments after completing their missions to Mir (e.g., deployment of large antennas or solar reflectors). At their end-of-life, Progress-M vehicles are loaded with refuse and destructively deorbited, usually over the Pacific Ocean.
The Mir core module, which serves as the principal space station control element, contains the main computers, communications equipment, kitchen and hygiene facilities, and primary living quarters. A small airlock is available for experiments or for the release of small satellites or refuse. The forward end of the Mir core module is configured with five docking ports (one forward and four radial) to receive logistics spacecraft and to attach four large permanent modules. Although the Mir core module's main propulsion system has not been operational since the arrival of Kvant 1 in 1987, this central module serves as the principal propellant storage unit and assists in controlling the attitude of the entire space station.
The smaller Kvant 1 module contains a suite of scientific instruments for astrophysical observations and materials science experiments as well as attitude control devices (gyrodynes) designed to improve the stability of the space station and to reduce propellant consumption. It is also the site of two girders (Sofora and Rapana) erected by cosmonauts on the outside of Kvant 1. While both structures are used for a variety of experiments, the taller (15 m) Sofora tower was equipped in 1992 with a roll-control engine, the precursor to a Russian unit now under development for ISS.
The Kvant 2 spacecraft is called the "additional equipment module" due to its large amount of equipment created for improving living conditions and operations in the overall complex. Kvant 2 carried electrolysis units (Elektron and Vika) to provide oxygen from recycled water; a new, large-capacity water supply system (Rodnik); two separate water regeneration systems; new sanitation facilities; a new shower; and a compartment designed to enhance extra-vehicular activities (EVAs). Several life science, materials science, and Earth observation instruments are also installed on Kvant 2.
The Kristall module was created to expand experiments in five major scientific fields: materials processing, biotechnology, biological studies, Earth observations, and astrophysical research. As its name implies, the module's major equipment was dedicated to materials science investigations. Kristall was also fitted out with two additional universal docking ports (APAS-89), which evolved from the APAS-75 docking system created for the Apollo-Soyuz Test Project in 1975. This new system was tested successfully in 1993 and was used by Space Shuttle mission STS-71 in the first Shuttle-Mir docking in June, 1995.
The addition of both the Spektr and Priroda modules by the end of 1995 will increase the utility of the Mir Space Station. Spektr has recently been added to Mir, and Priroda is scheduled for launch before the end of 1995. Both modules are equipped with a variety of Earth observation instruments, as well as other experiments for materials science, space technology, or space science. Equally important will be the increased power generation capability they will provide. Their arrival will essentially complete the Mir assembly process, resulting in an orbital facility of approximately 140 metric tons (see Chapter 3 for the principal parameters describing the Mir Space Station at this stage). Current plans call for the Mir Space Station to be operated until at least late 1997, when construction of ISS will commence.
During the nine-year operation and maintenance of the Mir Space Station, EVAs have proven invaluable and highly effective. Forty EVAs were performed in the 1987-1994 period (average of five per year) for a total of 344 man-hours outside the space station. In addition to permitting the installation and removal of scientific experiments on the exterior of the orbital facility, EVAs have been used to correct a docking problem with the Kvant 1 module; to repair scientific instruments, a rendezvous antenna, an EVA hatch, and a Soyuz-TM thermal control system; to test manned maneuvering units; to install additional solar arrays; and to construct the Sofora and Rapana trusses.
The Mir Space Station provides opportunities for wide-ranging scientific and technical experiments. Often, the Mir operational program is structured to concentrate on specific scientific disciplines (e.g., Earth observations or materials sciences) for several days or weeks to increase the efficiency of crew support. During the period 1992-1993, the relative proportions of investments in experiments were technical experiments (40 percent), remote sensing and environmental experiments (24 percent), technological and biotechnological experiments (15 percent), astrophysics experiments (13 percent), and medical and biological experiments (8 percent). The following sections highlight some of the hundreds of pieces of major equipment and instruments which have been operated on the Mir space station.
The principal life sciences experiments surround the physical well-being of the Mir Space Station crews, including initial adaptation to the microgravity environment, physiological changes during short- and long-duration missions, and readaptation to a 1-g environment upon return to Earth. The extensive USSR/CIS experience on space stations has led to the refinement of a number of practices and devices that can either monitor the physiological effects of near-weightlessness or be employed as countermeasures to prevent unnecessary and potentially harmful effects.
In part by trial and error, Russian medical experts have determined that two hours of strenuous exercise (normally one hour in the morning and one hour in the evening) are necessary to maintain acceptable circulatory and muscle conditioning. A treadmill and a bike (Veloergometer) play a central role in this regimen. In addition, "penguin suits" (coveralls with elastic straps) may be worn up to eight hours a day to place axial loads on the body. Prior to the return to Earth, the Chibis pneumatic vacuum suit is worn for extended periods to help redistribute blood to the lower body. Several medical monitors (e.g., Aelita, Gamma 1, and Lyulin for use inside Mir and Beta-8 for use during EVAs) are available to compile the extensive medical database required for research into the effects of prolonged human space flight. An ultrasonic cardiograph (Argument) has also been employed by and on Mir cosmonauts.
Life sciences experiments with plant and animal life have been many and varied during the history of Mir operations. In 1989 the Inkubator 2 apparatus arrived with the Kvant 2 module and has been used in several attempts to hatch Japanese quail eggs and monitor their development under microgravity conditions. Unfortunately, the first such experiment in March 1990 fell far short of its goals, lasting only 22 days out of a planned 233-day investigation, when all the hatchlings failed to adapt and perished. Later experiments with older quail proved more successful.
The Magnitogravistat installation was used to monitor the effects of varying both gravitational and magnetic forces on plant growth, including the interaction with bacteria in the soil. Several types of botanical units using normal soil or hydroponics (e.g., Bioterm, Fiton, Rost, Svet, and Svetoblok-M) have been tested with one goal: to discover the means of sustaining plant growth as a possible source of foodstuffs in a closed ecosystem, particularly on interplanetary voyages. Cellular fusion was the subject of experiments with the Rekomb bioreactor in 1990. Another bioreactor, Vita, has supported cellular cultivation experiments.
In addition to research concerned with the effects of microgravity on living organisms as noted above, numerous materials processing, biotechnology, and fluid-flow experiments have become routine for each Mir expedition. A large number of diverse electric furnaces (e.g., Gallar, Korund-1M, Krater-V, Kristallizator, Optizon, Zona-2, and Zona-3) have been operated using conventional and halogen lamp heating. Some of these devices qualify as pilot production units, for example, capable of producing 5 cm diameter gallium-arsenide crystals. Semiconductor samples from the Zona-2 and Zona-3 electric furnaces (temperatures up to 1800 degrees C and 1400 degrees C, respectively) can be 3 cm in diameter and 30-36 cm in length. Optizon was designed to produce silicon monocrystals via crucibleless melting techniques, and Krater-V can be used for week-long experiments to produce zinc-oxide crystals.
Biotechnological experiments, particularly those employing electrophoresis (e.g., EFU Robot, Ruchey, and Svetlana devices) and protein crystal growth (e.g., Aynur and Biokrist devices) have been popular on Mir. Electrophoretic experiments have included purification of blood and the production of high-quality interferon and anti-influenza preparations. Mir experience has shown that the purity and separation quality of electrophoretic experiments under microgravity conditions can be more than 100 times better than those on Earth. The Ruchey device is a higher productivity unit and utilizes a technique of moving fluid through an electric field to permit four methods of electrophoresis. Due to sample storage requirements and the need to examine the samples as soon as possible, biotechnology experiments are often conducted on Mir shortly before a normal crew rotation so that samples can be returned to Earth in a timely manner. Some protein crystal growth experiments have taken as long as two and a half months to complete.
Examinations of fluid flow in space have used the Pion-M to investigate thermocapillary convection and Kvant 2's Volna 2 apparatus. Pion-M, which was transferred from the Salyut 7 Space Station to the Mir Space Station in June 1986, uses a transport tray to observe nonuniformities in fluids injected with markers. Better understanding of fluid flow under microgravity conditions is vital to the design of water distribution systems, propellant transfer systems, and the like. Chemical reactions in microgravity have been the subject of experiments with the Biryuza apparatus.
Mir space science encompasses a number of scientific disciplines, including astrophysics, solar system physics, and geophysics. The arrival of the Kvant 1 module with its 800-kg, multinational Roentgen X-ray Observatory and the USSR-Swiss Glasar ultraviolet telescope at Mir in April 1986 was fortuitous because it closely followed the Supernova eruption in the Large Magellanic Cloud in late February of that year. The Roentgen X-ray Observatory contained four main instruments: (1) German HEXE high-energy scintillation spectrometer, (2) USSR Pulsar X-1/Spektr-3 X-ray telescope, (3) ESA Sirene-2 high-pressure gas scintillation proportional spectrometer, and (4) UK-Netherlands TTM coded mask imaging spectrometer. The Vedma X-ray spectrometer was developed by Germany for Kvant 1 to conduct observations of charged particle radiation in magnetic fields of neutron stars. In 1988 the Rozhen electro-optical device with a Paralax-Zagorka image intensifier was first used for astrophysical observations. Kristall's arrival in 1990 brought the Glasar 2 ultraviolet telescope and the Marina telescope to study cosmic radiation.
Several instruments have been installed in the Mir Space Station to observe various solar-terrestrial phenomena and interactions. The Mariya magnetic spectrometer on Kvant 1 measures high-energy electron and positron fluxes in near-Earth space. In January 1990, two cosmonauts on an EVA installed the Arfa-E device on the exterior of Kvant 1 to investigate the Earth's ionosphere and magnetosphere by injecting electron beams perpendicular to the geomagnetic field. Similar experiments have been conducted in conjunction with other, unmanned, Earth-orbiting satellites. During the testing of the Soviet-manned maneuvering unit in 1990, one of the cosmonauts carried the Spin-6000 instrument to measure the radiation of the Mir Space Station induced by the constant bombardment of cosmic radiation.
Mir's orbital inclination of nearly 52o enables it to view most of the planet, including the most densely populated zones, and thus serves as an excellent platform for Earth observation. Its extended longevity in orbit also permits the evaluation of potential regional or global changes. Besides frequent observations of the Earth by trained cosmonauts, the Mir Space Station offers an array of sophisticated and high-quality instruments to record this vital information. From hand-held Hasselblad cameras to high-precession topographic camera systems (KAP-350, KATE-140, and Sever) to multispectral (MKF-6MA) and high-resolution (Priroda 5) cameras to optical, infrared, and multispectral spectrometers (MKS-M, MKS-M2, ITS-7D, Skif, and Spektr-256), the Mir Space Station offers a full range of Earth observation devices. Typical photographic resolutions vary from the 5 m Priroda 5 to the 10-15 m MKF-6MA to the 50 meter KATE-140. Also available are photometers (EFO-1 and Terra) and other instruments (AFM-2 and PCN) used especially for atmospheric studies and a video spectropolarimeter (Gemma 2) for multipurpose remote sensing.
Mir's multifrequency observation capabilities will be increased significantly with the attachment of the Priroda module which will carry multiband scanning radiometers (IKAR-D and IKAR-N), a panoramic radiometer (IKAR-P), several spectrometers (ISTOK-1 IR, MOZ-OBZOR, MSU-E, MSU-SK, and OZON-M), a synthetic aperture radar (Travers), a French lidar (Alisa), and the refurbished German modular optoelectronic multispectral stereo scanner (MOMS) previously flown on the U.S. Space Shuttle. Together these instruments will support a six-point research program for (1) determination of the atmosphere-ocean system characteristics, (2) measurements of the land local characteristics, (3) measurements of optical characteristics of the atmosphere, (4) investigation of the sea surface roughness state, (5) comparison of radiation and reflection characteristics of the sea surface in the microwave range, and (6) measurements of the concentrations of trace gases in the atmosphere.
Perhaps the broadest area of Mir scientific research is in the development of space technologies for future applications, both in space and on the Earth. Space technologies include not only specific systems or components but also research that will lead to new or improved systems or components. Many of the systems operating on Mir today are the result of years of testing and development on earlier Soviet space stations.
Major Mir systems include the Elektron and Vika electrolytic water decomposition facilities; the gyrodynes for station attitude control; the Igla and Kurs rendezvous systems; the APAS-89 docking system; the Luch satellite data relay system; the Argon 16B, Salyut 5B, and EVM computer systems; the Burs, Korona, and Tranzit-A communications and data transmission systems; the ASPG-M movable instrument platform; the Orlan-DMA EVA suit; the Ljappa module relocation system; the Rodnik water supply system; the YMK manned maneuvering unit; the VDU roll-control engine unit; the Strela exterior crane; and the Vozdukh atmospheric CO2 removal system.
A number of space technology experimental devices include the Sofora and Rapana girders, the Yantar electron beam evaporizer, the Electrotopograph-7M used to study protective and dielectric construction materials, the TIGR holographic television system for studying the degradation of space station portholes, and a large number of investigations into the effects of the near-Earth environment on various materials such as ferromagnetics, polymers, and composites (e.g., Meduza, Ferret, Danko, Etalon-D, and Plenk-3).