Barrier of the Unknown (Russian: Барьер неизвестности, romanized: Barier neizvestnosti) is a 1961 Soviet science fiction drama film directed by Nikita Kurikhin.

Far away in the Central Asian steppes a test site is hidden where new jet aircraft are being tested, including an experimental aircraft with a rocket engine on atomic radioactive accelerators, deployed from under the wing of a carrier aircraft and capable of making a suborbital crewed space flight - to reach a thermosphere altitude of 100 km, as well as speeds over 7,200 km / h. The pilot-engineer Sergei Fyodorovich Baikalov and the research officer Vera Borisovna Stankevich are sent to this range.

The situation is complicated by the fact that Kazantsev shortly before the disaster told about the glow he saw in the flight around the body of the plane, Vera Stankevich was called to investigate the mechanism.

In addition to the fact that many projects similar to American rocketplanes and orbital planes were conducted in the USSR, according to the reports of authoritative American publications such as Missiles and Rockets magazine, US military analysts reported the existence of the USSR's functional (non test-object) aerospace flying apparatus of a similar class, as indicated by a number of features.

[4] During an interval in shooting, cinematographer's assistant Yuri Gakkel, who was the illegitimate son of Mikhail Kalatozov and the fiancé of actress Yevgenia Uralova, drowned.