The Soviet Buran orbiter that made the Soviet Union's first successful (though unmanned) space shuttle takeoff and landing on November 15, 1988, will not be launched again. The No. 1 Buran was built without a life support system, full avionics and fuel cell electrical system, and modifications to the aircraft would be too costly and difficult. The No.2 Buran, however, is nearing full completion and is scheduled for flight - possibly to the Mir space station - in 1991, though the first Soviet manned shuttle flight is now not expected before 1992.