2K, often referred to as Ptichka, is the second Buran-class orbiter, produced as part of the Soviet/Russian Buran programme. Although 2K was the closest to being completed of any of the Buran-class orbiters, it was never finished. The program was officially cancelled in 1993, at which point the shuttle was 95-97% complete. The proposed official name for 2K was Burya.

The Buran programme, also known as the "VKK Space Orbiter programme", was a Soviet and later Russian reusable spacecraft project that began in 1974 at the Central Aerohydrodynamic Institute in Moscow and was formally suspended in 1993. In addition to being the designation for the whole Soviet/Russian reusable spacecraft project, Buran was also the name given to orbiter 1K, which completed one uncrewed spaceflight in 1988 and was the only Soviet reusable spacecraft to be launched into space. The Buran-class orbiters used the expendable Energia rocket as a launch vehicle.