Kenneth Glad
Cold War submarine operations created difficult communication challenges beneath the ocean. One unusual Soviet story later appeared in an American intelligence document.
A 1975 Defense Intelligence Agency document describes an experiment that Soviet scientist Pavel Naumov said occurred around 1956, according to HistorieNet.
The test was reportedly intended to explore whether an unexplained biological connection between a mother animal and its young could persist over long distances. If such a link existed, researchers may have seen potential relevance to the persistent problem of communicating with submarines while they remained underwater.
Naumov said a mother rabbit was kept at a laboratory on land while her newborn offspring were taken aboard a submerged Soviet Navy submarine. Researchers attached electrodes to the adult to monitor its brain activity. The young animals were then killed one at a time aboard the vessel, and Naumov claimed that changes appeared in the mother’s readings at corresponding moments.
The supposed reactions were interpreted as a possible telepathic connection. The document, however, provided no evidence that the recorded responses demonstrated actual telepathy.
In the 1950s, both the Soviet Union and the United States were developing submarines that could stay underwater for much longer periods, making communication with them a growing challenge.
That was one reason researchers were interested in methods that might allow messages or signals to reach a vessel without forcing it to surface.
Underwater contact demanded trade-offs
Seawater absorbs radio energy quickly, so communicating with a submarine below the surface was much harder than sending an ordinary radio message. The US Naval History and Heritage Command notes that very low frequency, or VLF, signals could be used to reach submerged submarines, but the system came with practical limits.
Receiving VLF messages could require long trailing-wire antennas, which affected how a submarine could manoeuvre and how deep it could remain while maintaining contact. The system also had limited bandwidth, so it was better suited to short instructions than to large amounts of information.
Extremely low frequency, or ELF, signals could reach submarines at greater depths, but that advantage came at a cost. Data could only be sent at a very slow rate, making ELF useful for brief messages rather than detailed communication.
A US Department of Defense report for fiscal 1986 said the technology was intended to reduce the need for submarines to keep antennas at or near the surface. That gave crews more freedom to remain deeper while still receiving messages. The complete US two-site ELF network became fully operational in 1989.
Sources: HistorieNet; US Naval History and Heritage Command; US Department of Defense FY1986 Annual Report; 1975 US Defense Intelligence Agency report
