Mir Space Station

The heart of the station was a 20.4-ton core module, placed in orbit in February 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-diameter (3-m) cylinder attached to a 13-ft-diameter (3.9-m) cylinder by a tapered segment. One side of the module housed living quarters, 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-long (5.7-m), 13-ft.-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 off of 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 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-long (13.6-m), 14-ft-diameter (4-m) 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 astronauts 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. long, 14-ft. 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 wide, the module was designed for remote sensing studies of 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 long, 14-ft wide module incorporated optical systems to study the Earth resources. Lacking solar arrays, however, Priroda was unable to generate its own power, relying instead on batteries or on the Mir power network.