SOKS, or System Obnarujenia Kilvaternovo Sleda (russian: Систем Обнаружения Кильватерново Следа, "wake object detection system"), is a nonacoustic

submarine detection system Submarine detection systems are an aspect of antisubmarine warfare. They are of particular importance in nuclear deterrence, as they directly undermine one of the three arms of the nuclear triad by making counter-force attacks on submarines possib ...

created by the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

. SOKS functions by detecting

radionuclides A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

from the nuclear reactor in submarines, chemical signatures, and changes in the

refractive index In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

of water in the wake of submarines. It was first installed on the ''November''-class K-14 submarine in 1969. SOKS was revealed in a 1972 document written by the Central Intelligence Agency Directorate of Science & Technology and declassified in June 2017.

References

{{reflist Anti-submarine warfare Submarine detection systems Soviet inventions