A recent technology quarterly about new quantum innovations, published in The Economist, referred to a disturbing development in quantum sensor technology:
Military types are interested, too. “You can’t shield gravity,” says David Delpy, who leads the Defence Scientific Advisory Council in Britain’s defence ministry. Improved gravity sensors would be able to spot moving masses under water, such as submarines or torpedoes, which could wipe out the deterrent effect of French and British nuclear submarines.
So much of the present nuclear balance of power (such as it is) depends on ballistic missile submarines being essentially invulnerable by virtue of being impossible to locate. Reportedly, almost no crew members about an American boomer (as subs carrying nuclear missiles are known) know the precise location of the ship, and nobody on land has the information.
If states suddenly feel their subs are vulnerable, it risks two big effects. First, it raises tensions in a crisis. If states fear they will lose their seaborne second strike capability, they may be inclined to launch a nuclear attack earlier. Second, if the safest leg of the nuclear triad (along with bombers and land-based missiles) suddenly seems vulnerable, it’s likely they will assemble and deploy more weapons in more locations, wasting money and raising the risk of accidental or unauthorized use.
As with other emerging nuclear-related technologies like hypersonic weapons, it would be better for everyone if we could agree to prohibit sensors that threaten subs. Alas, states are rarely so cooperative or trusting.
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PUGET SOUND, Wash. (Sept. 28, 2016) The Gold Crew of the Ohio-class ballistic-missile submarine USS Kentucky (SSBN 737) transits the Hood Canal as the boat returns home to Naval Base Kitsap-Bangor following a routine strategic deterrent patrol. Kentucky is one of eight ballistic-missile submarines stationed at the base, providing the most survivable leg of the strategic deterrence triad for the United States. (U.S. Navy photo by Petty Officer 1st Class Amanda R. Gray/Released)160928-N-UD469-034
Mutually assured detection: Better anti-submarine warfare will mean fewer places for subs to hide
VISION is useless in murky water. To deal with that deficiency dolphins have evolved sonar. They emit clicks and interpret the echoes to find their prey. But not all marine mammals are so equipped. Seals, for instance, have no sonar, yet that does not stop them finding distant meals as effectively as dolphins can. This puzzled researchers for years, until they discovered that the secret lies in the animals’ whiskers—which they are now trying to copy, to develop novel underwater sensors.
An object moving through water leaves a series of miniature whirlpools in its wake. This trail is called a Karman vortex street. And that is what seals, using their whiskers, follow. As Michael Triantafyllou of the Massachusetts Institute of Technology (MIT) observes, “You can set a harbour seal loose to follow a towed fish, and even 30 seconds later they will be able to follow the exact track, whether it’s straight or zigzag or circular.”
Dr Triantafyllou and his colleagues at MIT’s Centre for Ocean Engineering are one of several groups studying how seals do this. A rival team, led by Ben Calhoun of the University of Virginia, and involving the University of California, Santa Cruz; the Naval Undersea Warfare Centre Division at Newport, Rhode Island; and Woods Hole Oceanographic Institution, has recently completed a three-year investigation of the matter. Other projects are under way at Jeju National University in South Korea and at Cleveland State University.
Seals can pick up the trail of fish such as herring when blindfolded and wearing earmuffs. Cover their whiskers, though, and supper eludes them. The bases of seal whiskers are rich in nerve cells, making them as sensitive as human fingertips. But that is not all there is to it. Under a microscope, seal whiskers are not circular when sliced through, as might naively be expected. Instead, they have an oval cross-section. Moreover, those whiskers’ surfaces have an elaborate undulating geometry.
Many of the capabilities of the new smallsats already existed, but mostly as government projects or as secretive intelligence operations. America has long sought to inhibit the commercial development of radar satellites, so powerful are their surveillance properties. Military radar satellites, which bounce radio waves off the surface of the Earth in order to build up a detailed picture of it, were said to be capable of detecting enemy submarines by measuring the tiny disturbances that their wakes left in the curvature of the surface of the ocean.
China’s quantum submarine detector could seal South China Sea | New Scientist
https://www.newscientist.com/article/2144721-chinas-quantum-submarine-detector-could-seal-south-china-sea/
China’s Underwater Great Wall – Washington Times
https://www.washingtontimes.com/news/2016/aug/30/chinas-underwater-great-wall/
The CSSC model appears to be a vastly advanced and comprehensive version of the Sound Surveillance System that had accorded the United States a significant advantage in countering Soviet submarines during the Cold War. The system was comprised of an array of hydrophones on the ocean bottom connected by undersea cables along the entire U.S. East Coast to onshore processing centers
America’s most recent review of nuclear policy concluded that “There are no known, near-term credible threats to the survivability of the ssbn force.” But what is near-term, and for that matter credible, is a matter of opinion. In 2020 a panel of experts assembled by the National Security College of the Australian National University concluded that, “The oceans are, in most circumstances, at least likely…to become transparent by the 2050s.” Trends making it harder to hide above the waves—more numerous and more capable sensors and more powerful ways of sifting through their output—are at play underwater, too.
To put a submarine at risk you must first detect it, then track it. Since the 1980s America and its allies have relied on the hydrophone arrays of the Fixed Distributed System (fds) for such detection. The sensors, tethered to the sea floor, float at a “critical depth” where acoustical geometry shields them from extraneous noise and makes the faint sounds of a submarine passing overhead stand out. America now has fds systems in both the Atlantic and the Pacific, with ships, submarines and aircraft available to set about tracking anything they detect.
https://www.economist.com/technology-quarterly/2022/01/27/finding-submarines-is-likely-to-get-easier