On May 31, 1990, the Soviet Union launched a new module to the Mir space station.
The new component was named Kristall, and it was the third addition sent to Mir since the core module launched in 1986. Including the core module, Mir consisted of seven different modules. Each of them launched individually on Russian Proton rockets, with the exception of one that went up on the space shuttle Atlantis in 1995. Mir was the world's first modular space station to be assembled in orbit. Kristall was 45 feet long and weighed about 20 tons. The module consisted of two main sections. One section was dedicated to experiments with materials science and biotechnology as well as astronomical observations. The other section was used as a docking compartment that would allow American space shuttles to visit the station. Kristall lifted off from the Baikonur Cosmodrome in Kazakhstan and docked with Mir 10 days later.
