Recently, Russian state television has increasingly threatened NATO coastlines, especially Britain, with ‘Poseidon’ strikes as ‘punishment’ for their anti-Russian stance. But beyond these threats, there is no evidence of the system’s existence.

The successful use on December 15, 2025, by Ukraine of the “Sub Sea Baby” Toloka underwater drone against a Project 636.3 “Varshavyanka” submarine — a platform for Kalibr cruise missile launches — in the port of Novorossiysk, where remnants of Russia’s Black Sea Fleet had fled from Crimea, originally inspired my short series of articles on Russia’s so-called “unparalleled” weapon systems. This time, the subject of investigation is the underwater system “Poseidon.”

Faced with external isolation, sanctions pressure, and internal demographic stagnation, the Russian government has intensified its rhetoric of strategic superiority. Against a backdrop of dwindling financial resources (the officially declared federal budget deficit for 2025 is 2.7 trillion rubles, while the HSE Development Center estimates the real deficit may exceed 4 trillion), technological degradation, and mobilization exhaustion, statements are made trumpeting “unparalleled” weapons systems. They are in truth attempts to compensate for a series of strategic failures: on the battlefield in Ukraine and in the international arena, the loss of attention of the US President—which is critically important to Putin—and complete indifference to Putin’s “threats” from world leaders.

Rhetoric without Confirmation

On October 29, 2025, during a visit to the Central Military Clinical Hospital named after P. V. Mandryka in Moscow, Putin told wounded soldiers that “we conducted a successful launch with a nuclear power unit. Everything worked.” That same day, at a meeting of the Demography Council, he repeated the same phrase, adding: “we not only launched it using a submarine engine, but also activated the nuclear power unit for the first time.” The same wording in two unrelated contexts – a sign of ritualistic declaration, though one unsupported by technical evidence.

Despite the pomp and publicity of statements by top state officials, neither the general public nor the world at large has been “convincingly” shown the existence of this “incredibly bold in concept and flawlessly embodied in metal and non-metal” weapon, which is supposed to terrify hostile states the world over. Instead of terrifying footage depicting the launch of an enormous underwater vehicle, of its confident movement slicing through the depths of the world’s oceans toward an “endless” voyage—what we get is a barely audible, repetitive soundbites from the Russian leader.

When assessing the practical realities of Poseidon, there’s much to be skeptical about:

  • Navigation Impossibility. The claimed range of “Poseidon”— up to 10,000 km — implies autonomous movement in the oceanic environment. However, underwater navigation without satellite support is impossible. The GLONASS system does not work underwater. Ocean currents, magnetic anomalies, depth variations—from coastal zones to areas over 6,000 meters — make set courses unstable. Without surfacing or using buoys, the vehicle cannot verify its route. This rules out stable course correction and makes movement dependent on external conditions beyond control.
  • Acoustic Vulnerability. At a claimed speed of up to 180 km/h, the vehicle would generate an extremely powerful acoustic signature. Analytical reviews describe it as “an acoustic trail comparable to a wounded whale” — persistent, low-frequency, easily distinguishable. This signature is detected by the SOSUS system — a global network of underwater acoustic stations capable of tracking object movement over thousands of kilometers. The vehicle thus becomes acoustically transparent and vulnerable.
  • Thermal and Radiation Signature. To move underwater at 180 km/h requires thrust comparable to that provided by a reactor with a capacity of at least 15–20 MW. This figure results from evaluating water resistance, the vehicle’s mass (about 100 tons), and the need to overcome hydrodynamic drag at depth. Putin stated that the reactor is “100 times smaller than on a submarine,” but even with such miniaturization, heat release in the active zone remains critical. At high speeds, temperature in the heat exchanger rises, and the vehicle becomes a source of constant infrared radiation. This trail is detected by patrol aircraft (e.g., P-8 Poseidon) and satellites with hyperspectral sensors. Without radiation shielding, the vehicle becomes a source of gamma radiation visible from space. With shielding, its mass increases to tens of tons, requiring additional ballast compensation and reducing maneuverability. The reactor, when operating at nominal power, does indeed release relatively constant thermal energy. However, the visible external infrared signature depends not only on nominal power, but also on heat dissipation modes, speed and movement regime, heat exchanger efficiency, and masking systems. At high speeds, coolant flows increase, boundary layers shift, turbulence and heat transfer efficiency rise—all of which increase the observable temperature contrast of the hull and tail section. Moreover, the compact “mini-reactor” must have dense layout and thin shielding, making effective dissipation difficult without amplifying external infrared and thermal indicators.
  • Warhead Mass. Putin claimed that Poseidon’s warhead yield exceeds that of Sarmat. If Sarmat carries a charge of up to 2 Mt, Poseidon—according to estimates—up to 100 Mt. The mass of such a charge is no less than 5–10 tons. This requires complex ballast compensation, increases the vehicle’s dimensions, and reduces its stability during maneuvering. All this, considering the need for periodic depth adjustments, creates constant demand for both longitudinal and transverse balancing—and all this without satellite navigation support.
  • Control Infrastructure. An unmanned underwater vehicle without control systems and a command-and-control network is merely a hull with an engine. By “control infrastructure,” I mean: an integrated navigation and course correction system, loading and combat control mechanisms on the carrier, communication and telemetry channels, launch and monitoring procedures, test ranges, and ground data processing centers. The absence of public signs of such elements means there is no evidence of autonomous planning, targeting, monitoring, or safe mission completion. It is infrastructure that turns an idea into a functioning weapon; its absence severely undermines confidence in the claimed implementation.

Poseidon remains a project without confirmed implementation, without testing, and without any demonstration of control infrastructure. The vehicle is claimed to be deployed aboard the Belgorod submarine, yet no launch from this platform has ever been shown or detected. The entire construct remains ritualistic: no loading, no sea deployment, no control system, no image of the actual device—even in a muted, retouched version. This all mirrors the conclusions of a previous article on Burevestnik, where the technical impossibility of the declared concept was demonstrated, along with the underlying motives for its emergence; that is, once again, a desire to compensate for a series of strategic failures on the battlefield in Ukraine and in the international arena.