| The Mir module, the first module of the complex
placed in orbit, is the main module of the station. It provides docking
ports for the other modules to attach to. There are five docking ports
on the transfer compartment of Mir module. One along the long axis of the
module, and 4 along the radius in 90 degree increments. There is another
docking port on the stern of Mir module. The various modules that are attached
to the docking ports can be moved around to different configurations.
Mir is the culmination of the Russian space program's efforts to maintain long-duration human presence in space. The permanently-manned space station has regularly hosted 2 to 3 cosmonauts (on occasion up to 6, for shorter periods of up to a month). Living in space, scientists perform scientific and technical experiments, and are able to record real-data on life in space. Mir provides the facilities for wide-reaching research ranging from space life sciences, microgravity, and space technology experiments, to Earth observation and sciences, and space sciences. Under certain circumstances the space station Mir can easily be visible to the naked eye. These conditions may occur after sunset or before sunrise: in the evening, when it's already dark at the observer's site the space station at an altitude of 400 km is still lit by the sun, or in the morning, when it's still dark down at the observer's site but Mir above already circles in the sunlight. For a fixed observing site, phases of visibility alternate with phases when Mir cannot be observed. Visibility phases typically last one to two weeks. Phases when Mir cannot be seen are zero to six weeks long. During a visible pass, one can see Mir like a bright star travelling across the sky in a few minutes. At such a pass, one can sometimes observe how Mir enters the Earth's shadow or exits from it. During an evening visibility period, entries into the shadow may sometimes be observed, during a morning visibility period, exits from the shadow may sometimes be seen. Sometimes one can see two spacecrafts flying on parallel courses. The second spot of light, somewhat less bright, is usually a manned Soyuz-TM spacecraft or an unmanned Progress-M cargo spacecraft shortly before docking to Mir or shortly after undocking. Such missions take place several times per year to exchange the crew and bring up supplies. In preparation for the construction of the International Space Station, Space Shuttles (Atlantis, Endeavour and Discovery) have visited Mir nine times between 1995 and 1998. During the approach of the Shuttle prior to docking to the Station or after undocking on the flight home, there is a chance to see both spacecraft simultaneously in the sky. In this case, the Shuttle is moving on a trajectory similar to Mir and also looks like a very bright star. |