In 1964, Soviet Defense Ministry issued a 5-years military space plan,
that included the "Spiral" space-plane project. The MiG 105-11 EPOS was
planned as an experimental manned spacecraft, that was under development
in Mikoyan bureau as a part of the Spiral program. The Spiral space system
consisted of an orbital spacecraft (MiG 105) with a rocket booster and
supersonic aircraft-carrier (Tupolev Article 50). After completing its
orbital mission, the spacecraft would be re-entry to earth's atmosphere
with the wings set as a 60-degree that served as the vertical stabilizers.
The program started without leadership support in 1965. Also due to the
technical difficulties, only the MiG 105-11 was built. The first flight
was planned to take place in 1967, but was delayed 10 years later in
October 1976. Totally eight flight tests were made that included air-drop
launches from a Tu-95K Bomber. In 1978, the program was ended as the
funding was halted for the new Buran Shuttle program.