Spy Submarine: Russia's AS-31 Losharik

Updated: Originally posted 22nd September 2016

Original artwork. CLICK for HIGH-RESOLUTION image.

Spy Submarine: Russia's AS-31 Losharik

Few other submarines are the subject of so much speculation and interest as the elusive and Top Secret Losharik (AS-31, sometimes referred to by her previous number AS-12) deep-diving special missions / engineering boat ('deep nuclear station (AGS)', read 'spy sub'). She is operated by the Russian Navy on behalf of GUGI (Main Directorate Deep Sea Research). On 1st July 2019 a fire occurred in which 14 of the crew died. RIP.

Actual Photo
*Memorial to the 14 dead hydronauts, Olenya Guba.

For the fateful mission the host submarine, BS-64 Podmoskovye, first called at Severomorsk. She arrived on June 24. I believe that Losharik was already under her. They were accompanied by a Pr.949A OSCAR-II Class cruise missile submarine (SSGN). That is possibly a coincidence, but it could also be for protection during some phases of the mission.

Also in attendance was the Pr.941 TYPHOON Class SSBN TK-208 Dmitriy Donskoy, which was later reported to have been involved in anti-submarine exercises around this time. It is unclear whether there is a connection between the presence of all three submarines. For BS-64 the stop-off in Severomorsk may have been to load torpedoes. They left around midday on June 25, five days before the fateful accident.

Original artwork. CLICK for HIGH-RESOLUTION image.

On the afternoon of July 1 a fire broke out in the battery compartment of Losharik. The submarine is constructed from seven spherical titanium hulls strung together, except for the uninhabited rear two which contain the nuclear reactor and machinery. The orb-like hulls, although not visible from the outside thanks to a streamlined outer hull, are where the submarine’s nickname comes from.

The accident occurred very close to the Russian coast, reportedly as Losharik was docking with the BS-64. The fire was in the battery compartment; even nuclear submarines have batteries as a backup. Some of the crew, including the captain, reportedly stayed in the affected compartment to ensure the safety of the others. These are the men who perished.

Losharik was able to dock with the BS-64, which raced back to Severomorsk to unload the injured submariners. By midnight a local news outlet, SeverLife.ru, broke the story. They reported that between 10 and 14 people died and that about 5 injured. Two of them were in intensive care. The story was later removed.

A camouflaged shelter was placed over a hatch on BS-64’s back. Onlookers may have been unaware that the injured submarine was out of sight, attached to the bottom of the visible host submarine. While the story was still making headlines around the globe, on July 4 BS-64 discretely slipped back to Olenya Guba. There special attention continued, with the camouflaged tent used again.

Host submarine BS-64 seen at pier in Severomorsk, 3rd July 2019 (69° 5'42.45"N, 33°26'47.42"E)

This wasn't Losharik's first underwater accident. In 2012 she damaged her manipulator arms while on a mission under the Ice Cap. That time it was not fatal. Losharik will likely be returned to service. In the meantime BS-64 has been exercising with a smaller battery powered submersible attached to her back, possibly as a surrogate. The ‘state secret’ missions will go on.

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She is the successor of two earlier families of special mission subs which were built in the Cold War; the 40m long Project.1851 X-RAY Class and the 70m long Project.1910 UNIFORM Class. The X-RAYs were closely equivalent to the American NR-1 submarine except that they were designed to be carried under the belly of a larger submarine for greater secrecy. The UNIFORM had a similar mission but was larger and and had to carry itself to he mission. The Losharik combines the features of both these submarines being similar in size to the UNIFORM but carried beneath another submarine.

She is named after a Russian cartoon horse (Лошарик) which provides a clue about her unusual construction. The Russian Navy keeps her hidden from sight and despite years of popular interest relatively little is known about her. Over time there have been more photos leaking out but they are always grainy and have not yet revealed the special fit which is of course below the waterline. All the same some photo analysis, discussion with sources and educated guesses allows a reasonably accurate picture to be drawn:


Note that the specifications available online for this submarine are often incorrect. The below are best estimates.
Boat: AS-31 (Factory number: 210) "Losharik"
Class: Project 10831 (NATO: Norsub-5)
Laid down: 16th July 1990
Launched: 26th August 1995
Entered Service: 1997
Displacement: <1,000 tons
Speed: 10-11kts submerged (estimate)
Operating depth: 1,000m (3,300ft)
Length: ~70m
Beam: ~7m
Power plant: 1 x nuclear reactor driving a single screw. Estimated 5 MW
Crew: 25

Internal arrangement

There has long been speculation that, like its namesake, Losharik consists of a series of joined spheres. Analysis of satellite imagery of her in dry dock at Severomorsk confirms this, and allows us to say with some confidence that there are seven orbs. Spherical hulls are frequently used in very deep submergence submarines because they are a stronger shape than regular cylinders, but they are also less conveniently shaped for living in. Although the boat is about 70m long the internal space is much less than other submarines with similar dimensions and all the walls are curved. This does allow her to dive down to about 1,000m. The orbs are constructed from titanium alloy and contained within a streamlined outer hull giving the appearance of a regular submarine. The orbs are about 6m in diameter giving a total internal 'dry' volume of around 1,000m3, which is roughly equivalent to the average house in US. So imagine your home with thirty-five men, a nuclear reactor and no flat walls to put anything against!

The image to the right, from a Russian nuclear program publication, is believed to show the reactor compartment of Losharik:

7th (rear) Orb: This is probably for the motors. The batteries and emergency diesel engine (if there is one) are probably in forward compartments. There is a deck hatch although, assuming that the reactor section is unmanned, this would only be used whilst in dock.
satellite imagery

Original artwork. CLICK for HIGH-RESOLUTION image.

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Some source images

Actual Photo
Actual Photo

evidential illustration
Although heavily sanitized and not revealing the special mission equipment, this illustration from a Russian Navy source is regarded to be a good representation of the overall form and hints at many details
evidential illustration

Host Submarine

Like the earlier Project.1851 X-RAY Class midget submarine the Losharik is carried and supported in its operating zone by a modified ballistic missile boat. A converted DELTA-III STRETCH submarine is co-located at Deer Bay with Losharik.
The lower photo clearly shows the deepened hull below the former missile section which allows Losharik it dock

Secret Base: Olenya Guba

Loshark is the star of the show among a range of special missions boats based at the Russian Navy's Northern Fleet's Olenya Guba base. This base is one of several set up by the Soviets during the Cold War on the inhospitable but strategically important Kola Peninsular, far away from civilization. satellite imagery
satellite imagery
satellite imagery
Satellite images of the Special Mission submarine base on the Kola Peninsula (vicinity 69°12'58"N, 33°22'42"E) where Losharik is based in a covered dock (A). An older but still operable Project.1910 UNIFORM Class submarine is often moored in front of the hangar (B).

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