Ptichka (Russian: Птичка, "little bird"; GRAU index serial number 11F35 2K, Article 1.02 or OK-1.02) GRAU was a nickname for the second Buran-class orbiter, produced as part of the Soviet/Russian Buran programme. Although OK-1.02 was closest to being completed of any of the Buran-class orbiters (after the orbiter Buran), 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 OK-1.02 was Burya (Russian: Буря, "storm" or "tempest"). 
Ptichka was preparing for its maiden flight to perform the first fully regular Buran-class orbiter operation. (The flight of Buran 11F35 1K Article 1.01 was lacking regular thermal control and power systems.) This orbiter was also planned to receive a remote manipulator and docking system.
As of 1989 the orbital flight test program for the second orbiter was split into two missions, with a space station approach test on the second, but delays in preparations changed the plans to perform all test tasks in one maiden flight, scheduled for December 1991. The mission profile included:
In August 1995, 1.02 was moved into storage within the MZK building (Russian: МЗК, Монтажно-Заправочный Комплекс, Assembling and Fueling Facility) at Baikonur Cosmodrome, alongside the full size test article OK-MT. The media have speculated that Ptichka is the property of Kazakhstan-Russia Joint Venture Company Aelita, a subsidiary of RKK Energia.
In April 2021, OK-1.02 was vandalized with graffiti, including the word dobro (Russian: добро, meaning "good") on the right side of the orbiter. Photos of the graffiti surfaced on Instagram and Telegram on May 26 of that year, though by that time the orbiter had already been painted over. According to NASASpaceFlight.com, there is evidence that Roscosmos may have known about the vandalism and decided to cover it up.
The vandalism caused distress to many space enthusiasts. Roscosmos also expressed concern and expressed its belief that the Buran hardware at Baikonur Cosmodrome should be transferred to a museum, and that it would discuss the issue at the next Intergovernmental Kazakh-Russian Commission. Dauren Musa, the current owner of the orbiter, also expressed his concern about the state of the hardware, and stated that he would discuss the fate of his orbiters with Roscosmos.
NASASpaceFlight noted that the vandalism may have benefited the orbiters by drawing attention to their condition.
Buran vehicles registrywas invoked but never defined (see the help page).