India’s imminent test of a submarine-launched cruise missile (SLCM) marks a significant step in its naval modernization, strategic deterrence vis-à-vis Pakistan and rising competition with China in the Indian Ocean. The preannounced test, however, could serve to cool bubbling tensions with Pakistan.
This month, multiple media sources reported that India is set to test in March a 500-kilometer range SLCM from its east coast. The SLCM, developed by the Defense Research and Development Organization (DRDO), will likely be fitted on indigenously manufactured conventional submarines (SSK) planned by the Indian Navy under Project 75 India.
Project 75 India, also known as the Kalvari-class SSK, is a French-designed Scorpene SSK of which India has five and plans to have nine in service.
India’s new SLCM has two variants: the Land Attack Cruise Missile (LACM) and the Anti-Ship Cruise Missile (ASCM). Both feature technologies like thrust vector control, in-flight wing deployment and in-flight engine start.
The SLCM is also expected to be sold to friendly countries after being thoroughly tested and inducted into the Indian military.
Its capabilities are similar to the Nirbhay ground-launched cruise missile (GLCM), which has a 450-kilogram payload and an 800-1,000 kilometer range, according to Missile Threat.
The Nirbhay is launched from a land-based mobile launcher and can carry unitary or cluster high explosive warheads or a 12-kiloton nuclear warhead. It is equipped with a solid fuel booster motor jettisoned shortly after launch then switches to a turbojet engine with a speed of Mach 0.65.
The Missile Threat report says that an inertial navigation system (INS)/GPS receiver guides the Nirbhay and an indigenous Indian satellite navigation system can be used to improve its accuracy. India has also tested an SLCM version of its Brahmos supersonic cruise missile.
In March 2013, Brahmos Aerospace reported that the Brahmos SLCM was successfully launched from a submerged platform in the Bay of Bengal offshore Visakhapatnam.
Brahmos Aerospace says that the missile took off vertically from its submerged platform and followed a pre-determined trajectory for its full range of 290 kilometers.
Brahmos Aerospace claims that the Brahmos SLCM can be launched from a depth of 40-50 meters from a vertical modular launcher installed in the submarine’s hull and that it is identical to the ship-launched version.
The Times of India notes in a November 2023 article that the subsonic Nirbhay would complement the supersonic Brahmos, providing commanders with more options during a potential conflict.
Brahmos may be too expensive to deploy in large numbers, necessitating less-capable but lower-cost options such as the Nirbhay GLCM and India’s new SLCM to maintain precision long-range strike capabilities while saving Brahmos for critical targets.
Those developments align with India’s efforts to establish a dedicated rocket force encompassing GLCMs, SLCMs and short/medium-range ballistic missiles (SRBM/MRBM).
SLCMs would also add a survivable sea-based element to augment India’s land-based rocket force. In December 2022, Asia Times reported on India’s efforts to build a rocket force around the Pralay tactical SRBM, with 120 slated to be deployed in underground facilities in its border states with China.
Along with SRBMs and MRBMs, India may use SLCMs as the first salvo during the opening stages of a conflict to knock out rear facilities such as command and control (C2) posts, logistics hubs, airfields and communication nodes.
A second salvo would aim to destroy air defenses, artillery pieces, missile bases and tank formations, with rocket and gun artillery attacks finishing off troops in forward-deployed positions.
Missile Threat notes in a June 2022 article that India’s missile arsenal supports its nuclear deterrent against Pakistan and China. Pakistan and China’s recent advances in missile delivery systems give India the impetus to diversify its delivery systems and increase their survivability.
The successful test and subsequent integration of SLCMs onto submarines will significantly bolster India’s naval deterrence and power projection capabilities.
SLCM-armed Kalvari SSKs could complement the nuclear-powered Arihant ballistic missile submarines (SSBN) in their role as India’s sea-based nuclear deterrent.
India currently has two Arihant SSBNs with four units planned, which could be armed with the K-15 or K-4 submarine-launched ballistic missile (SLBM).
In an October 2022 article, Naval News notes that the K-15 SLBM can deliver a 1,000-kilogram warhead up to 740 kilometers, with the Arihant holding 12 missiles. However, Naval News reports that the K-15 may be an interim solution, with the upcoming K-4 having a range of 3,500 kilometers.
SLCMs would give India a sea-based delivery system for tactical nuclear weapons, although India’s nuclear posture focuses on strategic-level second-strike capability rather than tactical battlefield use.
Tit-for-tat, Missile Threat reported in January 2017 that Pakistan test-fired the Babur SLCM from a mobile underwater platform at an undisclosed location in the Indian Ocean.
Missile Threat says the Babur SLCM has a 450-kilometer range, underwater-controlled propulsion and advanced guidance and navigation.
However, the source says that several Indian news outlets attempted to debunk Pakistan’s 2017 Babur SLCM test, citing conflicting satellite imagery of the landscape as evidence.
Nevertheless, Missile Threat notes that the Babur GLCM can carry a 450-kilogram unitary or cluster high-explosive warhead or a 10- or 35-kiloton nuclear warhead up to 350-700 kilometers.
The source says the Babur features a terrain contour-matching (TERCOM) guidance system, with upgraded variants having digital scene matching (DSMAC) and satellite guidance.
India’s SLCM test may lead to a missile race between the two longtime adversaries. Saif-ul-Haq notes in a 2021 Islamabad Policy Research Institute journal article that the rapid modernization of the Indian Navy, including its acquisition of SLCMs, has compelled the Pakistani Navy to improve its conventional and nuclear capabilities.
Zawar Jaspal notes in a November 2023 article for WE News that complex security dilemmas, such as conventional asymmetry and lowering nuclear use thresholds, intensify as India and Pakistan increase their inventories of long-range and short-range missile systems.
That underscores the increasing need for confidence-building measures (CBM), direct communication hotlines and shared norms between the two nuclear-armed rivals.
However, Shea Cotton and Anne Pellegrino mention in a November 2019 Nuclear Threat Initiative (NTI) article that the same positive norms that Pakistan and India have developed for ballistic missile tests are comparatively weak for cruise missiles.
The writers note that the 2005 pre-launch notification agreement between Pakistan and India excludes cruise missiles, despite being negotiated during both countries’ early stages of cruise missile development.
They point out that the growing perception of cruise missiles as a crucial strategic asset and the fear that all such missiles could potentially be nuclear-capable make the lack of oversight even more worrying.
Even so, India’s announcement of its upcoming SLCM test marks a certain improvement in the area. Whether Pakistan reciprocates to lower regional tensions is yet to be seen.