The Growing Threat of GUGI, Russia’s Deep-Sea Research Directorate

Right now, a mechanical leviathan outfitted with ultra-modern intelligence and surveillance equipment manoeuvres beneath the Arctic ice cap. She weaves her path along the volcanic crevasses and ravines between the pack ice above and the depths below, constantly probing for undersea pipelines and communication cables. The leviathan's name is Podmoskovye, and she carries out her missions under the command of GUGI.

GUGI, or Russia’s Main Directorate of Deep-Sea Research, operates as one of the most secretive and covert components of the Russian Federation’s Armed Forces. Answering directly to the Russian Ministry of Defence, as opposed to the Russian Navy, their mandate is to dominate the seabed and project Russia’s power and influence to everything below the tide through both conventional and unconventional tactics. Their clandestine mission is to conduct research, surveillance, reconnaissance, and, at times, sabotage of critical underwater infrastructure (CUI).

Both Moscow and the West are aligned in their belief that civilian and military CUI is as imperative to protect as it is susceptible to damage or compromise. With over 97% of the world's telecommunication and vital underwater energy pipelines snaking their way along the ocean floor, the consequences of a successful, coordinated, and broad attack on critical underwater infrastructure would be both costly and devastating.

Picture the scene. It's morning. You're on your phone, thoughtlessly scrolling through Instagram while also trying to invest in the S&P 500. Suddenly, your social media feed freezes. Your online brokerage goes dark. Moments later, your house goes dark too, as does your neighbourhood, county and entire region. Unknown to you, at that exact moment, a Russian deep-diving UUV (unmanned underwater vehicle) has just severed multiple undersea pipelines and telecommunication cables near your coastal home. It did not operate unilaterally. GUGI has just conducted the first widespread and nearly simultaneous attack on critical underwater infrastructure throughout Europe.

An internet outage followed by power surges would be only the initial indication of catastrophe. By early evening, gas prices have skyrocketed to record highs and lines to fill up cars, trucks, and canisters form a blockade encompassing your local petrol stations. The gas and oil pipelines that, until yesterday, pumped like arteries into your country's beating heart have been severed. Fisheries are poisoned, and fragile ecosystems are irreparably damaged. The financial, military, ecological and political ramifications of this attack will echo for decades.

Thankfully, an overt attack of this scale on critical underwater infrastructure has not occurred yet, but make no mistake, GUGI is preparing to do this and more should the command come down. But how could they achieve such devastation?

GUGI is well-funded, operates with little oversight, and is tasked with conducting a mission that the Russian Ministry of Defence deems critical to Moscow’s current and future ambitions. To demonstrate what we mean, let’s briefly return to the dark seas below the Arctic. Podmoskovye is one of GUGI’s most capable assets, but it is far from alone. Affixed to its hull is Losharik. A deep-diving, manned mini-submarine that is designed to be carried under the hull of Podmoskovye, like a remora latched onto a shark.

Above and below them are acoustic intelligence gathering buoys and UUVs, all feeding precious intelligence to GUGI’s surface fleet loitering nearby. Surface vessels like Yantar and Evgeny Gorigledzhan act as mini-submarine motherships and are also equipped with acoustic and signals intelligence suites, constantly collecting, analysing and disseminating the tremendous amount of raw data they gather.

Flanking these vessels and skulking around the ocean floor are Russian hydronauts (operators of manned deep-sea vehicles) responsible for a myriad of missions in the maintenance and operation of GUGI assets. The intelligence collection effort is further bolstered by static underwater sensors, which can monitor both surface and submarine activity over vast swaths of water. The cornerstone of GUGI’s mission is the collection of acoustic intelligence and sea-bed mapping.

The goal of this collection effort is to create a comprehensive map of the ocean floor, providing a real-time view of the subsurface environment. This initiative aims to identify vulnerabilities, understand how sound propagates through different underwater settings, and analyse how adversaries operate in these regions. It seeks to establish where NATO can first detect Russian assets, the response times of other submarines to subsurface threats, and how noise generated by surface vessels or biological clutter might affect sound transmission on the ocean floor, among other goals.

The greater the amount and quality of intelligence GUGI can gather, the less likely their submarines or UUVs will be detected. By zooming out and seeing the entire battlespace holistically, Russia gains a better vantage point to identify precisely where it can strike without repercussions. They probe the ocean floor searching for the West's jugular, so when the final strike comes, it is a lethal one - or at least, so the Kremlin hopes.

But we’ll get onto the measures NATO is taking to counteract these abilities later on. For now, let’s quickly break down the range of weapons GUGI has in its arsenal, starting with three basic categories: Surface, Subsurface, and Other.

Surface: The vessels that comprise GUGI’s surface fleet are typically outfitted to conduct multiple missions simultaneously. Yantar and Evgeny Gorigledzhan, for example, can deploy mini-submarines overtly or discreetly, as well as repair and maintain them throughout prolonged deployment periods. Meanwhile, they can deploy arrays of towed sensors, allowing their analysts to gather acoustic data passively and potentially receive communication from their subsurface allies and assets.

Acoustic data or intelligence is a broad term that can mean multiple things depending on the platform collecting it; in layperson's terms, it involves devices that sit underwater and listen. On the more basic side, acoustic sensors can detect that something is creating noise (or operating) in the vicinity of the sensor, cueing a potential response from the military or the Coast Guard.

On the more technical side, modern acoustic sensors can monitor for specific frequencies, which can be used to determine the type (nuclear or diesel), class (Akula or Severodvinsk) or even the particular hull of the submarine operating nearby. Yantar is equipped with numerous hydrophones, arrays, and acoustic sensors used to carry out this mission, as well as seabed and CUI mapping.

Over the past decade, Yantar has sailed everywhere from Northern Greenland to Algiers and as far West as Cuba, often loitering over or in the vicinity of undersea telecommunication cables.

As a converted tug and with her reinforced hull and ice-class rating, Evgeny Gorigledzhan can venture into even more austere and precarious conditions in the Arctic. While underway, GUGI vessels are supported by small fleets of both civilian and military ships, some equipped to replenish and resupply the boats and others to aid in their intelligence collection efforts.

It is difficult to say with any certainty which vessels presently fall directly under GUGI, other than these two. However, GUGI’s mission has consistently proven to be a priority for the Kremlin, and the support and funding it receives mean that its missions have extended at least partially to vessels that traditionally fall under the Russian Navy. Furthermore, the dedicated GUGI fleet is set to expand dramatically over the coming decade.

Yantar will have two sister ships of the same class, which are expected to begin sea trials in the coming years. Due to its cost-effectiveness, more vessels like Evgeny Gorigledzhan will likely be converted in the future as well. Understandably, the branch of GUGI that is expanding its operations the most rapidly is the subsurface department.

Subsurface: GUGI operates numerous types of mini-submarines and UUVs that Yantar and Evgeny Gorigledzhan can deploy. Mini-submarines, also referred to as midget submarines by many military analysts, are typically one- or two-person vessels capable of conducting underwater research or intelligence collection at great depths. With tested depths reaching 6,000 metres and an endurance of up to 12 hours, even GUGI’s older models, such as Rus and Konsul, are highly competent in their mission.

Their newest, albeit untested, vessel, Sergei Bavilin, is reported to be able to dive to depths up to 11,000 metres. This would match the capability of the world record-holding DSV Limiting Factor, which was able to descend to 10,925 metres in the deepest known point of the ocean, Challenger Deep in the Mariana Trench.

Undersea cables are typically placed at depths of 200-500 metres near coastlines, with depths rarely surpassing 3,600 metres for trans-Atlantic cables or 6,000-8,000 metres in the Pacific. If GUGI’s claims are accurate about Sergei Bavilin, it would extend Russia’s ability to sever undersea cables throughout the entirety of the ocean, regardless of depth.

While Russia’s mini-submarines' larger counterparts cannot quite reach the abyssal depths of 11,000 metres, their mission is no less essential to GUGI; nor are they any less of a threat to or a drain on NATO resources.

The Podmoskovye, or Delta-IV in NATO parlance, is a specially outfitted Delta-class Ballistic Missile Submarine (SSBN). SSBNs were designed to and are prized for their ability to deploy submarine-launched ballistic missiles (SLBMs) covertly. They make up the most furtive and stealthy leg of the Nuclear Triad.

In a doomsday scenario, this is the craft that will send the nuclear-tipped missiles streaking through the skies towards American and European airspace. A final, apocalyptic salvo before the mushroom clouds plunge civilization back into darkness.

In her previous life, Podmoskovye carried out this task, involving long undersea deployments, while avoiding detection at all costs, thereby holding the West at risk of a Nuclear Strike. During her refit in 2016, she was frayed at the seams and Frankensteined together with other SSBNs.The result was an ultra-modern subsurface behemoth not only capable of carrying SLBMs but also acting as a capable mothership for Losharik and her future sister submarines.

Losharik is a manned, nuclear-powered deep-diving submarine typically deployed from another GUGI asset. While she has been reported to dive as deep as 2,500 metres, it remains highly likely that she can descend even deeper. With a complement of as many as 25 submariners, all of whom are officers, the term “mini-submarine” seems almost disingenuous to her true capabilities. Being able to sever or possibly even tap into underwater cables, a “spy submarine”, or the Russian preferred term, “nuclear deep-water station,” more accurately describes the full breadth of her speciality.

After a fire sent Losharik to dry dock for several years, she is slated to return to active service by the end of 2025. With her return to blue water, Losharik poses not only a credible threat to undersea cables but also significantly complicates anti-submarine efforts due to her small size and ability to operate independently of her mothership.

Also in GUGI’s arsenal is another refitted Soviet submarine, Belgorod, which conducts a similar, but slightly varied, mission set in the High North. After an extended period in the shipyard, the former Oscar II-class SSBN’s hull was lengthened from 154 metres to 184 metres, making her the largest seaworthy submarine in the world. Like Podmoskovye, Belgorod is equipped to carry midget submarines, such as Losharik, but also deploys Unmanned Underwater Vehicles.  However, she was additionally designed with the explicit purpose of carrying the Status-6 Oceanic Multipurpose System, better known as Poseidon.

Poseidon is a nuclear-powered, unmanned, autonomous nuclear or conventional warhead delivery vehicle. At over 20 metres in length, it is the largest torpedo ever designed, dwarfing traditional torpedoes at over 30 times their size and nearly double the size of most SLBMs. At its increased size and with a dramatically improved range and navigation system (10,000 kilometres to unlimited), Poseidon is closer to a nuclear-tipped UUV than it is to a torpedo.

Over the last three years, Poseidon has made the front page multiple times due to its reported destructive potential. In 2022, Moscow’s Chief propagandist, Dmitry Kiselyov, claimed Poseidon would create a “radioactive tidal wave…a tsunami up to 1640 feet high” able to “plunge Britain to the depths of the ocean.”

Military analysts assess that GUGI’s Belgorod can carry up to six Poseidon delivery vehicles. If Russia’s propagandists are to be believed (which they are not), this could transform the United Kingdom into a real-world Atlantis — six times over. While that claim smacks of good old-fashioned Russian sabre rattling, the destructive capability of Poseidon is, nevertheless, vast.

What's worse, GUGI’s ability to deliver nuclear warheads via Poseidon poses another complex challenge; that final nuclear salvo heralding armageddon can be achieved entirely underwater. Unlike a SLBM or ICBM, there is no opportunity to defeat the torpedo during its launch sequence, terminal, or midcourse phase, thus rendering traditional missile defence systems incapable of countering Poseidon. The threat now remains subsurface until it strikes.

There are a few silver linings that run through this otherwise dark cloud. Poseidon, like many of Russia’s emerging technologies, is almost entirely untested. The Kremlin has reported multiple successful tests of the weapon - although this is the same Kremlin that boasted it could take Kyiv in three days, so perhaps this should be taken with an entire restaurant’s worth of salt. In contrast to the Kremlin’s perhaps self-flattering assessment, the United States intelligence community, alongside other Western intelligence agencies, believe that some tests have failed and others are entirely fabricated.

There is no indication that Moscow’s 2027 operational deployment of Poseidon will proceed on schedule. While Poseidon’s touted destructive capability, inertial navigation system, and range have been deemed plausible by analysts, plausible is only good enough to push propaganda and prompt a Western response. Describing Poseidon as the “weapon of the apocalypse” is disingenuous to its actual capabilities and detracts from the pervasive threat of the remainder of the nuclear triad.

Still, the propagandist's claims do have some merit. When Poseidon comes into service, it will be able to produce tidal waves comparable to large tsunamis, which could be very destructive and disruptive to coastal cities. It is scary, it will likely be a threat in the coming decades, but it will not be invulnerable to defence systems, nor should it dramatically change the power balance in subsea warfare. Prior to speculating on what the future defences used to combat a future threat might be, let’s turn back to the subsurface threats that NATO is presently facing in the Atlantic and the High North.

Together, Podmoskovye, Belgorod, and Losharik carry out missions that their surface counterparts, such as Yantar and Evgeny Gorigledzhan, cannot. Nuclear-powered submarines can stay submerged and potentially undetected for as long as they have food to keep their sailors at their posts. They operate below the surface for prolonged periods, making it more difficult for NATO to account for their exact whereabouts.

With the ability to transit covertly, Podmoskovye, Belgorod, and Losharik are also tasked to deploy GUGI’s state-of-the-art seabed sensors. While Yantar and her acoustic intelligence-gathering counterparts are also capable of carrying out surveillance, sensor deployment, and seabed mapping missions, they must operate in full view of their targets, thereby losing a significant amount of the plausible deniability and secrecy that the Kremlin relies on so heavily.

While NATO anti-submarine assets are drawn to the SSBNs and SSGNs operating in Western waters, the Podmoskovye and Belgorod operate primarily in the High North and Arctic. Under-the-ice operations have become the forte of this duo, which provides critical intelligence to the Kremlin and extends its reach deep into and under the contested Arctic. Through their efforts in seabed mapping and extended operations, they have also helped to open up the Arctic to Russia’s traditional submarine fleet.

Other: GUGI, along with Russia’s intelligence network as a whole, has also begun utilising civilian merchant vessels, including their own Shadow Fleet, in their efforts. The civilian vessels, operating under the guise of legal maritime traffic, can sail near and even into an adversary's territorial waters without arousing suspicion. Equipped with intelligence collection technology, both sanctioned and unsanctioned Shadow Fleet vessels can contribute to GUGI’s missions.

In late 2024, in the wake of the destruction of CUI (undersea communication cables) between Finland and Estonia, the civilian Shadow Fleet vessel responsible for the destruction, Eagle S, was seized by Finnish maritime authorities. According to an article from Lloyd's List,  Eagle S "had transmitting and receiving devices installed that effectively allowed it to become a "spy ship" for Russia…Eagle S also dropped "sensor-type devices" in the English Channel during a transit.” The ability and willingness to utilise civilian vessels greatly expand GUGI’s potential sphere of influence; however, the investments they are making in future capabilities on the seabed and in their own backyard could have an even more profound impact.

GUGI is developing and implementing an underwater sonar tracking and monitoring system in the Arctic. The system has been named Harmony (also known as RUSOSUS). From military analyst and author H.I. Sutton, “The logical aim is to provide Russia with real-time tracking of the latest NATO submarines operating in northern waters. This addresses the NATO submarine advantage head-on and would allow persecution of prowling US-UK nuclear-powered attack submarines.”

Harmony is loosely modelled on the Cold War era SOSUS (Sound Surveillance System), which the United States employed along the Eastern Seaboard to identify and track Soviet submarines. Underwater sensors like SOSUS are designed to detect specific and general frequencies from tremendous distances and multiple sound propagation paths, enabling the identification of adversary submarines and surface vessels. Differentiating Harmony from SOSUS is the dramatic improvement of the technology GUGI has developed to support their network.

GUGI is also instituting a newer generation sonar system, the MGK-608M (SEVER). The SEVER Sonar system, currently already being utilised in the Barents Sea, “consists of a string of seabed short line arrays connected by undersea cables to ground stations which can be up to 200km away.” The SEVER will also be supported in its collection by existing sonobuoy arrays, which will provide acoustic collections at different depths, allowing operators to exploit multiple sound channels (the pockets where sound propagates further through water).

Together, these technologies will pose a formidable challenge for NATO vessels attempting to operate undetected in the Arctic. While the technical capabilities of these new arrays are not publicly available, what makes them truly worrisome is how GUGI intends to power distant portions of their Harmony seabeds.

Within 200 km of Russian territory, GUGI is able to utilize ground-based support equipment to power and monitor its undersea arrays. However, at further distances, they have developed small autonomous nuclear turbine generators (ATGU, when translated from the Russian Cyrillic alphabet) to support the Harmony network. Operating under the guise of civilian research and power generators, ATGU and Harmony have come under little scrutiny from the international community. Using mini-submarine motherships and midget submarines, such as Belgorod and Losharik, GUGI can deploy its networks and generators discreetly and without the assistance of its counterparts in the Russian Navy or surface fleet.

Pushing Moscow’s emerging undersea capabilities from concerning to alarming is the reported ability for the Poseidon missile to be launched from remote seabed installations. This significantly enhances Russia’s second-strike or even third-strike capability. Even with every airfield destroyed, every SSBN sunk, every ICBM defeated, Russian Poseidon nuclear delivery vehicles in the Arctic could continue the fight, acting as the profound linchpin of Moscow’s nuclear deterrence.

NATO and its allies will undoubtedly develop tactics and procedures to mitigate Russia’s power projection in the High North, but the development of sound and repeatable tactics takes time. There is a phrase in the military aviation community, “Standard operating procedures are written in blood,” and there is no reason to believe this would be any different for their undersea counterparts.

Over the last decade, Russian military doctrine has marched uniformly toward a willingness to utilise grey-space warfare tactics, including the destruction and disruption of critical water infrastructure. The confluence of conventional and unconventional tactics in undersea warfare is both the present and future state of the conflict. Between GUGI’s intelligence gathering apparatus and the Poseidon UUV, the Kremlin has seemingly never been better equipped to exert its power and interests underwater.

There is, however, some good news. Unsurprisingly, NATO has responded to GUGI’s growth and development. What exactly that means is hard to say definitively. The Kremlin’s strategic communications (STRATCOM) goals usually attempt to highlight the threat and technological advantage its military has over the West. Western powers typically emphasise the coordination and cooperation between their allies, rather than the destructive potential of their weapons. Suppose NATO is a pit viper, only showing its fangs when absolutely necessary. In that case, Russia is a rattlesnake constantly making noise to ensure the entire world knows exactly how deadly it is.

While the tactics to combat Moscow’s emerging threats may not be publicly known or fully developed, NATO is taking some measures that could mitigate GUGI’s influence.

First and foremost, numerous NATO members are rapidly modernising their submarine fleets. The US, UK and France are leading the charge in the development of modern nuclear SSBNs, ensuring the continuation and improvement of strategic deterrence patrols across all seas. Norway, Germany, and Sweden are jointly producing highly capable diesel-electric submarines, which, equipped with Air-Independent Propulsion (AIP), can remain submerged for extended periods, enabling them to patrol from littoral to deep-sea environments.

Canada, the sleeping Arctic giant that has allowed their forces to wither over the last several decades, has seemingly woken up and is replacing its older legacy submarines with Western Europe’s finest diesel-electric submarines. In the not-so-distant future, Canada will be able to effectively patrol the Northwest Passage and Western Arctic while the UK and Norway can deter Russian presence in the GIUK and Bear Gap. Even taking the largest and most capable submarine fleet out of the equation (America´s), the challenge posed by NATO’s Arctic and near-Arctic submarine forces will be challenging, if not insurmountable, for GUGI to combat.

The development and employment of UUVs on both sides of the conflict have accelerated dramatically since the invasion of Ukraine. Proven to be cost-effective and easily operable, NATO nations seeking to maximise their 5% GDP requirement are turning to UUVs to enhance their subsurface capabilities. Openly, GUGI’s UUV torpedo, Poseidon, does not have a direct foil from NATO, but the solution will likely be to fight fire with fire.

Remotely or manually launched UUVs reacting to discreet acoustic signatures made by Poseidon could track and intercept the weapon before it reaches its predetermined detonation location. Cutting-edge technologies, such as Anduril’s Copperhead UUV, equipped with AI and the ability to loiter for prolonged periods, could patrol near Poseidon launch sites to detect and engage in the event of their activation. To achieve the destruction of Poseidon faster, NATO submarines “could be used to launch long-range hypersonic glide vehicles with sub-sea payloads”, reaching Mach-5 prior to deploying their payload in the vicinity of Poseidon.

The West’s civilian defence sector has also stepped up its efforts in developing low-cost methods of monitoring CUI. Assets like DAS, or distributed acoustic sensors, are being implemented on both civil and military CUI, allowing companies or entities to monitor acoustic and seismic abnormalities in real time. While not currently employed in nearly enough CUI, both DAS and UUVs future employment in these areas can greatly increase undersea situational awareness.

Neither Washington nor Moscow has pulled ahead yet in this race. In a battlespace where the West is accustomed to having a vast technological and strategic advantage over its Russian adversary, at least in and under the High North and Arctic, GUGI is desperately trying to level the playing field. The continued development and employment of emerging technologies will be critical in NATO’s defence of its undersea infrastructure and power projection throughout the Arctic.

The combined might of the alliance’s subsea forces and intelligence apparatus may just prove to be a match for GUGI, but it will require the coordinated sharing of information and technology between NATO nations, who have historically been unwilling to relay current or future strategic defence intelligence. The development of new technology is important, but it is not enough on its own. If NATO intends to win this game of undersea chess with the Kremlin, it will need all its pieces on the board and a single, coordinated hand to move them, with a coherent and shared strategy in mind.

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