Brahmos Aerospace has indeed developed a vertically launched submarine variant of the missile, but the Indian Navy (IN) is yet to operationally deploy it for want of a suitable submarine.
The first test of the submarine variant of the missile was conducted on March 20, 2013 from a submerged platform in the Bay of Bengal, off the coast of Visakhapatnam.
According to the DRDO, "The missile took off vertically from the submerged platform for its full range of 290 kms. Following a pre-defined trajectory, the missile emerged from underwater, took a turn towards the designated target meeting all mission objectives."
Subsequently, a pontoon used earlier to test the K-15 Shaurya missile was modified to test the Brahmos submarine variant.
Aring was to be fitted in it to snugly fit the smaller diameter Brahmos.
In 2015, the submarine variant reportedly underwent a successful trial from a submerged pontoon.
The submarine variant of the Brahmos was developed keeping in mind the planned acquisition by the IN of submarines under Project 75I (India).
Development of the submarine launched variant was pursued to an extent that was platform agnostic. Customised development for a specific platform will be pursued after the Indian government chooses the submarine to be acquired under Project 75I.
Project 75I
Project 75I was approved in October 2014. Under the project six submarines were to be constructed by an Indian shipyard with transfer of technology from a foreign collaborator.
In 2015, based on the recommendation of a select committee it was decided that Project 75I procurement would be pursued under the strategic partnership paradigm.
The Strategic Partnership Model (SPM) aims to enhance indigenous capabilities by fostering collaboration between Indian private companies and foreign Original Equipment Manufacturers (OEMs).
Under this SPM, Indian firms shortlisted by the MoD (Ministry of Defence) locally build fighter jets, helicopters, armoured vehicles, and submarines in partnership with foreign OEMs.
Qualitative Requirements
According to Indian press reports, the Qualitative requirements (QRs) for Project 75I submarine platform include Air Independent Propulsion (AIP) and Land-attack capability (аt least 12 LACMs with 500-km range).
The Land Attack Cruise Missile (LACM) capability sought by the IN is in addition to an Anti Shipping Cruise Missile (ASCM) capability.
It's reported that the IN wants the Land-attack capability to be based upon a submarine segment fitted with vertically launched Brahmos missiles, in order to increase the overall firepower of the boat.
Procurement Progress
The DAC on January 21, 2020 cleared Mazagon Dock Shipbuilders Limited (MDL) and Larsen & Toubro (L&T) as strategic partners for Project-75I procurement.
The two shortlisted SPs together have tie up with five foreign OEMs – Daewoo Shipbuilding & Marine Engineering (now – Hanwha Ocean) (South Korea), Naval Group (France), Navantia (Spain), Rosoboronexport (Russia) and Thyssenkrupp Marine Systems (TKMS, Germany).
In 2021, the MoD issued a request for proposal (RFP) for the construction of six conventional submarines under Project 75I.
Technical Challenges
The IN's qualitative requirements have proven challenging for submarine OEMs worldwide. The IN wants to induct an Air Independent Propulsion (AIP) equipped submarine that has been operationally deployed.
Russia, France and Spain do have AIP technology but have not operationally deployed any AIP submarines. Submarine OEMs are betting more on lithium ion batteries for increased underwater endurance than AIP.
Only Germany's TKMS (U-212) and South Korea's Hanwha (KSS-III) have operationally deployed AIP equipped submarines. However, the ability of these operationally deployed submarines to accommodate an additional section for vertically launched LACMs poses challenges.
None of the vendors have an operational submarine with vertically launched LACMs.
Plugging an additional section into an operationally deployed submarine is fraught with risks because it will change the physical characteristics of the submarine, which in turn could negatively impact its stealth, speed and manoeuvrability characteristics.
It's unlikely that the qualifying OEMs will underwrite the risks involved in adapting their platform to Project 75I QRs.
BrahMos had contemplated adding a missile section to the fifth and sixth Scorpene boats to be manufactured at the Mazagon shipyard, but dropped the idea when the IN said it wanted to integrate air-independent propulsion to the last two boats.
Amur 1650
Russia's Rubin has offered to jointly develop with India a customised variant of the Amur-1650 to meet Project 75I QRs.
On July 9, 2019, Deputy Director of the Federal Service for Military-Technical Cooperation (FSMTC) Vladimir Drozhzhov told reporters that Russia offered India to build a submarine on the basis of Amur-1650 project. He added that the offer didn't imply licensed production, but to jointly design the boat and build the lead vessel.
Drozhzhov indicated that the ToT during project implementation would be total, allowing India to build a follow-up series on its own.
"Naturally, such cooperation would involve the transfer of all technologies for its creation. Moreover, we offer the installation of the BrahMos missile system on this boat. This project can be successfully implemented in the interests of the two countries", Drozhzhov stressed.
Russia says the jointly developed Project 75I submarine would be fitted with either the DRDO developed AIP or a Rubin developed AIP.
Conclusion
Curiously, Indian media coverage of Project 75I has stressed exclusively on the AIP capability of the submarine to be acquired, completely ignoring the IN's desire to pack considerably more firepower into the platform than what is available on Project 75 Scorpene submarines.
The IN needs to carefully balance its need for AIP and a potent land attack capability in selecting the Project 75I platform. The extent of ToT accruing from the acquisition will also weigh heavily in decision making.
India has already developed a submarine-launched variant of the Brahmos missile, the most destructive conventionally armed LACM in the world. Besides the need to protect our investments in developing the submarine variant there is also the fact that a better LACM is not available.
Anyway, it would not be in India's interest to acquire a submarine platform that makes us dependent on foreign weapon systems.
The export potential of such a submarine would be very high.