BAIKONUR, Kazakhstan -- A Soyuz space capsule ferrying two Russian cosmonauts and a German astronaut is expected to dock with the space station Mir on Tuesday, beginning the longest stay in space for a West European astronaut.


After executing an elaborate mating dance in the cosmos, the Soyuz and Mir should couple at approximately 2:30 p.m. in the skies over Kazakhstan.


Cosmonauts Anatoly Solovyov and Nikolai Budarin, aloft since July, will greet countrymen Sergei Avdeyev and Yury Gidzenko and welcome aboard Thomas Reiter, an astronaut from the European Space Agency.


Reiter, 37, will be on Mir for 135 days, considerably longer than U.S. astronaut Norman Thagard, who beginning last March set a three-month U.S. endurance record there. Reiter, the second ESA astronaut to work aboard Mir, was hurled into the skies Sunday after a flawless launch from the Baikonur Cosmodrome in Kazakhstan.


When Thagard returned from Mir, he expressed frustration at the lack of contact with his family and native culture. Reiter said at a pre-launch press conference that he has benefitted from a detailed debriefing by Thagard, and hopes to avoid a similar situation.


"A long-term flight is not just a walk in the park," he told reporters. Reiter began training for this mission in 1993, and has taken 680 hours of Russian language training. His Russian colleagues said he was an excellent guitar player and looked forward to hearing his music in space.


While not playing the guitar, Reiter will carry out a series of experiments designed to explore the effects of prolonged stays in zero gravity.


By simulating walking, Reiter hopes to counter the loss of bone mass, a well-documented side-effect of extended space travel. One of Reiter's heels will be struck 500 times over a ten-minute period each day, imitating the sensation of his foot hitting the ground. He will then measure the difference in bone density between his two heels with a bone densitometer.


On Oct. 20, Reiter will exit the space station and take a five-hour space walk, the first by an ESA astronaut. Later in the voyage, the U.S. Shuttle Atlantis will dock with Mir.


As Reiter strolls through the cosmos, science and technology ministers of the ESA member-countries will meet on Earth -- in Toulouse, France -- to discuss their possible participation in an international space station.