Mir Space Station

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Mir Space Station

The longest continuous presence of humans in space began in 1989, with the Soviet launch of a 20.4 ton cylinder that formed the core of the space station called Mir. In Russian, mir means world and peace. By 1996, six modules had been linked to complete the sprawling station, which has been likened to a space-borne assembly of tinkertoys. To build Mir, the Russians drew from lessons learned with the Salyut stations of the 1970s and 1980s. The stations were simple and robust, but compact and with limited lifespans. Engineered from the beginning for expansion, Mir was designed for regular resupply, and with nearly self-contained oxygen, power, and water generation capabilities.

Designed for five years in orbit, the station remained space borne until deliberately deorbited in a spectacular reentry on March 23, 2001.

During its operational lifespan the station provided a zero-gravity laboratory for humankind, and saw the dawn of true international cooperation in planning joint space missions. Mir outlasted its creators. Launched by the Soviet Union, it was deorbited by the Russian Federation space program.

Design and construction

The heart of the station was a 20.4-ton core module, placed in orbit on February 19, 1986. The core module included two axial docking ports, but its most important features were the four radial berthing ports that permitted the attachment of expansion modules, some of which were linked to other modules.

With solar arrays generating more than 10 kilowatts (KW) of power, the core module provided basic life support and command services. The 43-ft-long (13-m) module consisted of a 10-ft (3-m) diameter cylinder attached to a 13-ft- (3.9-m) diameter cylinder by a tapered segment. One side of the module housed living quarters, while the other contained the space station operations, communications, and command center. Although the zero gravity environment made orientation irrelevant, the module was still outfitted with an up/down configuration—fluorescent lights on the ceiling and green paint on the walls—to make the cosmonauts (Russian astronauts) feel more at home.

The next component connected to the station was the Kvant module, launched into orbit in 1987, and attached to one of the axial ports of the core module. Divided into pressurized and non-pressurized areas, the 19-ft (5.7-m) long, 13-ft (3.9-m) diameter module was originally designated as the astrophysics laboratory. Kvant also provided nearly 7 KW of power from solar cells, and incorporated a gyroscope-based assembly that operated from solar energy to orient the Mir complex in space without the use of precious fuel. At the far end of the module was a docking area for the unmanned Progress drones that arrived from the Earth at intervals to fit the station with supplies; once emptied, then refilled with trash and waste, the drones were released to fall back toward the planet, burning on re-entry.

Launched in 1989, the Kvant II module was attached to one of the radial berthing ports on the core module. The 45-ft (13.6-m) long, 14-ft (4-m) diameter module produces 7 KW of power from solar cells and featured three pressurized segments. The main compartment contained instrumentation and apparatus such as an oxygen generation system and another that converted humidity in the Mir atmosphere into drinking water. A second compartment contained a toilet and shower facility. Through a complex series of filtration and processing steps, a unit on the module cleaned and recycled water from the sanitary facilities for reuse. Kvant II also featured a compartment with an extra-vehicular activity (EVA) airlock that allowed cosmonauts to exit the complex for spacewalks.

Launched in 1990, the Kristall module was initially berthed at a radial port opposite Kvant II; it was later moved to a different radial port 90^° from its initial position. Although it is mainly used for storage, the 45-ft (13.7-m) long, 14-ft (4.3-m) wide module also offered astronauts a small taste of home with a greenhouse designed to allow botanists to study the effects of zero-gravity conditions on plant growth. Kristall featured a retractable solar array that generated between 5.5 and 8.4 KW of power. When the space shuttle began operations with Mir in 1995, the docking module that allowed the ship to mate with the station was attached at the far end of the Kristall module.

In May 1995, the Spektr module flew into orbit and was docked in Kristall’s old position, at the radial port opposite Kvant II. More than 42 ft (12.7 m) long and 14 ft (4.3-m) wide, the module was designed for remote sensing studies of the Earth, and provided living quarters for visiting astronauts from the United States and the European community. The module also produced significant amounts of power from four 370 ft² (33.3 m²) solar arrays. Severely damaged in a 1997 docking mishap, the module remained useless thereafter.

The final unit segment of Mir was the Priroda module, placed in orbit in 1996—ten years after the core module, and five years beyond the planned lifetime of the station. The 42-ft (12.8-m) long, 14-ft (4.3-m) wide module incorporated optical systems to study the Earth’s resources. Lacking solar arrays, however, Priroda was unable to generate its own power, relying instead on batteries or on the Mir power network.

Collaboration

In 1994, the United States made an historic $400 million deal with Russia to place six American astronauts on Mir for durations of up to six months. Ostensibly an arrangement designed to prepare American crews for duty on the International Space Station (ISS) by exposing them to long periods in orbit, the deal also had political implications. With the collapse of the Russian economy, the Russian space program was in jeopardy, and with it, Russia’s commitment to provide crucial elements for the ISS, such as the habitat module. Although NASA officials insisted the Mir deal brought important experience and data to the ISS program, many viewed it as a thinly disguised subsidy for the Russian space program.

Despite the wear and tear of more than a decade in space, the station functioned surprisingly well until 1997, the year that contained a number of mishaps. In February, an oxygen canister burst into flames, filling the living module with smoke. When the cosmonauts, turned to extinguish the flames, they discovered that the launch restraints on the firefighting equipment had never been removed, and spent valuable time searching in near darkness for tools to free them prior to extinguishing the flames.

In subsequent weeks, the main carbon dioxide removal system failed. Then, the cooling system malfunctioned, leaking coolant into the air and forcing the shutdown of the drinking-water reclamation system due to contamination. Temperatures in the modules remained at 96^°F (36^°C) for weeks.

In June, the station suffered the most dangerous setback. During the test of a new docking system, an unmanned rocket collided with the Spektr module, piercing the hull and crumpling solar panels. During the scramble to seal off the module, the astronauts were forced to disconnect cables that snaked from Spektr’s solar panels into the other modules of the station, leaving Mir with only partial power. Days later, the steering units broke down, and then a power surge knocked out a computer. The cosmonauts were forced to use precious fuel from the Soyuz escape pod to reposition the station, turning the solar panels toward the sun.

In July, the cooling system failed again, then the main computer crashed, an event that would repeat itself time and time again in coming months. In September, the U.S. Space Command center sent out a warning that a military satellite was in an orbit that would pass dangerously close to Mir. About the same time as the warning was received, the main computer on the station failed, leaving the cosmonauts aboard to simply watch tensely from the Soyuz escape pod as the MSTI-1 satellite passed 1,000 yd (910 m) away.

As the month dragged on, the station suffered repeated computer failures, as well as failure of the carbon dioxide removal system and leaks of mysterious brown fluid. Amid reports that the Russians were ignoring scheduled parts replacements as a cost-cutting measure, concern for the safety of American astronauts aboard the station mounted. The four year collaboration ended in mid-1998, as the seventh American astronaut came back to the Earth.

With the launch of the ISS approaching, and the continued problems at Mir, the Russians initially announced plans to intentionally de-orbit the station in September 1999, dropping it into the sea. As the appointed date drew near, however, the space agency seemed less and less inclined to terminate the station. Privately held RKK Energia actually owned and maintained Mir. It pledged to dig up the $100 million annually required to keep the station in orbit. Eventually, the effort to maintain the station became resource exhausting and a decision to make a controlled deorbit was inevitable.

Almost 100 cosmonauts/astronauts spent time on the space station during its lifetime, and countless experiments provided data to help scientists better understand the effects of the space environment on humans and materials. The ISS has and will continue to benefit from the lessons learned with Mir.

See also Space probe; Spacecraft, manned.

Resources

BOOKS

Burrough, Bryan. Dragonfly: NASA and the Crisis Aboard Mir. New York: HarperCollins, 1998.

Harland, David M. The Story of Space Station Mir. Berlin, Germany, and New York: Springer, 2005.

Launius, Roger D. Space Stations: Base Camps to the Stars. Washington, DC: Smithsonian Books, 2003.

Linenger, Jerry M. Letters from Mir: An Astronaut’s Letters to His Son. New York: McGraw- Hill, 2002.

Morgan, Clay. Shuttle-Mir: The United States and Russia Share History’s Highest Stage. Houston, TX: Lyndon B. Johnson Space Center, National Aeronautics and Space Administration, 2005.

Zimmerman, Robert. Space Station: The Story of the First Interplanetary Space Ships. Washington, DC: Joseph Henry Press, 2003.