Angles and Dangles: Arihant and the Dilemma of India’s Undersea Nuclear Weapons


Editor’s Note: This is the 24th installment of “Southern (Dis)Comfort,” a series from War on the Rocks and the Stimson Center. The series seeks to unpack the dynamics of intensifying competition — military, economic, diplomatic — in Southern Asia, principally between China, India, Pakistan, and the United States. Catch up on the rest of the series.

After INS Arihant, India’s first ballistic missile submarine (SSBN), finished its maiden deterrent patrol in November 2018, Prime Minister Narendra Modi emphatically declared India’s nuclear triad complete. Arihant’s operationalization has catapulted India into a select group of states with an underwater nuclear launch capability. It has also raised alarm over the safety and security of India’s nuclear arsenal because a sea-based deterrent may entail a ready-to-use arsenal and less restrictive command and control procedures, increasing probability of their accidental use. For Pakistan, India’s nuclear force modernization endangers the balance of strategic forces in the region and could intensify the nuclear arms race on the subcontinent.

Modi’s triumphalism belies Arihant’s modest capabilities. The submarine does not add substantially to India’s second-strike capability — at least, not yet. Until and unless India deploys an SSBN fleet carrying missiles with intercontinental range, which could take decades, its sea-based deterrent vis-à-vis China will lack credibility. And for deterring Pakistan, India’s air and land-based nuclear arsenal is sufficient.

If triumphalist assertions about Arihant are unwarranted, so, too, are alarmist concerns over the safety and security of India’s underwater nuclear arsenal. India’s Strategic Forces Command has done much more to ensure robust command and control at sea than many commentators acknowledge. India’s sea-based nuclear assets are neither on hair-trigger alert nor are they in the hands of the military. They remain firmly under the control of political decision-makers.

Arihant’s operationalization is an opportunity for New Delhi to reflect upon its nuclear trajectory. With China and Pakistan as nuclear adversaries, India confronts a unique challenge. It has to build up its nuclear capability enough to ensure that Chinese decision-makers fear it, without sending Islamabad into panic and undermining regional stability. This “Goldilocks dilemma” will be difficult to resolve, and India should not leave it to chance — especially as the United States, once South Asia’s chief crisis manager, loses both interest and influence in the region. India should reassure Pakistan by reaffirming its policy of no first use of nuclear weapons and a retaliation-only nuclear doctrine. More importantly, India should rethink its deterrence requirements vis-à-vis China.

Ultimately, the risk is that India will fail to achieve its aim of deterring China while unintentionally provoking its smaller rival. Understanding how India reached this stage in its nuclear trajectory and how it is trying to manage this challenge requires examining the peculiar history of its ballistic missile submarines as well as its robust efforts to enhance civilian control of its nuclear weapons.

Project Samudra and the Burden of History

The peculiar history of India’s long quest for a nuclear submarine leaves a long shadow over Arihant’s capabilities.

India’s nuclear submarine program began in 1966 with feasibility studies on marine nuclear propulsion. Rather than being driven by any military necessity, the program was influenced by considerations of the nuclear establishment’s organizational prestige. As Homi Bhabha, father of India’s nuclear energy program, argued at the time, maritime reactors “could demonstrate India’s impressive capabilities in the field of nuclear energy.” Military justification for the program came much later when, during the 1971 Bangladesh war, the United States sent the aircraft carrier USS Enterprise into the Bay of Bengal to support Pakistan. Thereupon, as a conventional fighting platform, nuclear attack submarines attracted the attention of the Indian Navy because they could raise the threshold of superpower intervention in the region. However, the nuclear scientists could not produce a viable marine reactor. In the early 1980s, therefore, the Indian Navy turned to the Soviets for assistance.

In April 1982, the Soviet Union agreed to lease an attack nuclear submarine (SSN) to the Indian Navy and provide technical assistance to India in building its own submarines. This was the beginning of Project Samudra (Project Ocean), which was to include two vessels codenamed S-1 and S-2.

The stated intent was to produce a “cost-effective deterrent against Pakistan’s enlarging military machine,” according to a top-secret report explaining the program that I obtained from a former government official. The larger objective of these acquisitions, however, had little to do with nuclear deterrence — it was directed towards the growing naval presence of the great powers in the Indian Ocean, more focused on conventional operations than nuclear issues. The report stated, “more significantly, such acquisitions would enhance India’s credibility particularly in view of the increasing presence of the outside powers in the Indian Ocean.”

Project S-1 culminated with the loan of a Soviet Charlie-class SSN in 1988. Project S-2 paved the way for the establishment of the Advanced Technology Vessel (ATV) Directorate, a dedicated research and development agency responsible solely for building an indigenous SSN. The project suffered major delays as India’s nuclear establishment continued to face technological hurdles in producing a viable reactor design. Still, the path was set: India was designing and developing a nuclear attack submarine.

The Indian and Pakistani nuclear weapons tests of 1998 changed the nature of India’s nuclear submarine program. Indian decision-makers were keen to explore avenues that could render their nuclear forces more survivable, including placing nuclear weapons at sea. The first step towards building a sea-based deterrent was to place modified Prithvi missiles on board two Sukanya-class missile boats. The ATV Directorate, however, soon proposed modifying the nuclear attack submarine into a strategic weapon system. The navy was also keen to have its share of the nuclear pie. Thus, soon after the 1998 nuclear tests, India decided to convert what was originally designed as a nuclear attack submarine armed with cruise missiles for conventional naval operations into a strategic weapon system for nuclear delivery. Project S-2 became the first of India’s SSBNs.

Yet this revised mission left the program highly limited in its capabilities. India had started developing a 300-km earth-skimming cruise missile called Sagarika with Russian help in 1991. When India decided to convert the attack submarine into an SSBN, the size of the boat and its missile block was fixed based on the earlier SSN design — meaning only a modest missile with limited range could be retrofitted in. The only option was to replace the Sagarika cruise missiles with ballistic missiles that could carry a one-ton nuclear warhead. Today, the limited range of the K-15, the primary weapon system on Arihant, is the result of these post-hoc technological fixes. Arihant can carry 12 of these 750–1,000-kilometer range missiles, barely sufficient to hit a few major cities in retaliatory strikes against Pakistan, let alone Chinese targets. Its small reactor size also restricts its endurance at sea. In fact, the nuclear reactor onboard Arihant is of vintage Soviet design. Arihant is not Pakistan-specific by design but only by default: Its technological evolution rendered it incapable of anything else.

The burden of history continued to inform the trajectory of India’s SSBN program. To achieve meaningful deterrence vis-à-vis China, India not only needed more SSBNs, but also longer-range missiles that could strike deep inside Chinese territory. In the early 2000s, the Indian government, therefore, sanctioned the ATV Directorate to produce two more SSBNs of the S-1 type and to increase the range of the missiles to 3,500 kilometers. The increase in range entailed a consequent decrease in the number of missiles. The problem, again, was the fixed size of the submarine: Given the immutability of the S-1 design, the long-range missile could only be accommodated by increasing the missile diameter and reducing the total payload. But reduction in nuclear payload meant lesser bang for India’s buck, since it reduced the number of nuclear weapons it could deploy at any given time against China.

When the cabinet of ministers pointed out this problem in 2004, the ATV Directorate decided to include another missile block by increasing the length of the next two boats. Yet in 2006, a major technical review of the program concluded that all five boats proposed so far fell short of a true SSBN force capable of deploying intercontinental ballistic missiles (ICBMs) that could reach all parts of China. It also required a nuclear reactor double the size of previous boats that could endure longer operations at sea. The review committee recommended a new class of boomers with a reactor double the size of previous S-Class boats and capable of launching ballistic missiles in excess of 6,000 kilometers. S-5, as the boat is officially designated, was approved in 2015. This evolution of Project S is symptomatic of mission creep in India’s deterrent requirements, especially as it attempts to achieve deterrence parity with China. The piecemeal expansion of India’s nuclear submarine program severely undermines its deterrent capability. Until India fields an SSBN fleet with ICBM capabilities and improves upon the designs of its nuclear propulsion package, its sea-based deterrent will remain a paper tiger. As Admiral Arun Prakash estimates, it will take India “50-60 years” to field a credible SSBN force.

Arihant’s historical evolution also leaves doubts about its robustness and reliability. There are more than a few rumblings within Indian Navy circles regarding reactor designs based on second-generation Soviet submarines. Arihant’s first deterrent patrol lasted merely 20 days, suggesting endurance issues with its nuclear propulsion package. Finally, the Indian Navy would have to develop very robust infrastructure for training, maintenance, and repair of its SSBN fleet before the sea-based deterrent could be realized. In fact, the fleet has recently suffered from a series of accidents, including the 2017 mishap onboard Arihant. Only extensive operational experience will build the required confidence both in the men and the machine.

Given the twists and turns of its nuclear submarine program, the resulting technological limits, and the underlying problems with Soviet legacy platforms, Arihant’s first deterrent patrol is just a modest beginning in India’s effort to deploy a credible nuclear triad. For the prospective future, its nuclear deterrent will continue to rely on the land- and air-based legs. Indian decision-makers must accept the reality of this modest enterprise. Rather than engaging in premature triumphalism over Arihant, India should take a page from the Chinese playbook to hide its capacities and bide its time.

Operationalizing Deterrence at Sea

Even though Arihant, in its current form, has limited utility against China, its operationalization has nonetheless raised serious questions about how India would deploy its nuclear submarine force, whether this will entail a “ready-to-use” arsenal, and whether India has developed a sufficiently elaborate command and control mechanism to avoid unauthorized use of nuclear weapons. Such alarmist reactions, however, do not fully capture the efforts India’s Strategic Forces Command has made in establishing operational protocols for its SSBNs. The command’s standard operating procedures for the nuclear triad alleviate three major concerns. First, a sea-based deterrent would not engage in conventional operations, nor does it automatically translate into a “ready-to-use” arsenal. Second, custody of India’s nuclear weapons has not necessarily been delegated to the military. Last, India’s political leadership will maintain firm control over nuclear assets.

First, as far as deployment is concerned, India is most likely to follow a bastion strategy rather than putting its SSBNs on constant patrol in open seas. A “bastion” or a “citadel” model entails operating submarines in waters close to home and away from hostile forces. In India’s case, the most suitable geography is in the Bay of Bengal, the Andaman Sea, and in the Northern Indian Ocean. The Pakistani Navy has very limited capability to operate in these waters, while India’s overwhelming naval presence through its conventional fleet and anti-submarine warfare operations will be able to create a cordon sanitaire against Chinese submarine activity.

While some fear the nuclear submarines will have a dual (nuclear and conventional) role, my interviews with Indian Strategic Forces Command officials suggest otherwise. The nuclear submarines will remain solely under the operational command of the Strategic Forces Command, which handles nuclear forces, rather than the Navy, (which handles conventional naval forces). A clear division of labor between the two has been codified, reducing the risk that Indian nuclear forces at sea could get entangled in conventional operations.

In fact, Indian SSBNs would not operate alongside the Navy’s conventional fleet as any coordination could lead to the nuclear submarines’ exposure by enemy intercepts of fleet communications.

Relatedly, the operationalization of Arihant does not mean India’s nuclear weapons are now on hair-trigger alert. It is highly unlikely that the submarines will carry a nuclear payload during peacetime. In fact, insofar as India’s SSBN force will not perform constant patrols armed with nuclear weapons at all times, it does not entirely fit the definition of a true triad. India’s operational plans for its nuclear submarines consist of a three-stage process. The first is nuclear alerting, or mechanically mating missile launch tubes with missile canisters armed with nuclear weapons at specialized naval facilities. This would start at the first indications of a crisis situation (Strategic Forces Command defines a crisis not as the start of actual conflict, but any scenario where Indian decision-makers foresee a possibility of military escalation with Pakistan or China). The second stage involves dispersing the submarines on deterrence patrol. It is only after the boats receive political authorization that they will maneuver to predetermined positions to prepare for the eventual launch of nuclear weapons. This strategy does entail a risk of a “bolt from the blue” nuclear strike against India’s major naval bases, but decision-makers are willing to run this risk given the other legs of the nuclear triad and the inherent uncertainty that any first strike would eliminate all its nuclear assets. Since at least 2008, Strategic Forces Command has consistently strived to develop and put into practice such operational plans for India’s SSBN force.

Lastly, India has developed an elaborate command and control apparatus to maintain firm political control over its sea-based nuclear assets. When the submarines encounter a crisis situation, nuclear weapons will be physically mated with ballistic missiles, per the first of the three steps described above. For this reason, India needed positive command-and-control mechanisms to ensure that when authorized a launch will always occur and that unauthorized or accidental launches never occur. Former Strategic Forces Command personnel have told me in interviews that India has developed such mechanisms: Even after nuclear weapons have been mated with missile tubes, the military will not be in command of nuclear weapons. Any ballistic missile launch requires a two-step authorization, in which civilian authority plays a key role. Even in situations where an imminent enemy strike may be about to take out the submarine’s ballistic missiles, civilian authority will remain the sole custodian of India’s sea-based nuclear forces.

These operational procedures would require extensive testing and training, and a robust communications network. Strategic Forces Command has to establish beyond doubt that the controls will work under the fog of war and that decisions will be securely communicated to the submarines’ battle stations. The infrastructure for these communications has grown alongside the SSBN program, but will still take a lot of time to mature and attain operational effectiveness and reliability. These concerns will continue to cloud the readiness of India’s SSBN force.

Thus, Arihant’s operationalization should not lead to a conclusion that its nuclear weapons are now fully mated with delivery systems and that control has shifted to the military, as many alarmists seem to fear. India has strived to ensure complete political control of its nuclear assets at sea, ruling out any unauthorized use.

Indeed, Arihant’s problem is not that it has nuclear weapons on hair-trigger alert, that it suffers from loose command and control, or that it increases the risks of accidental nuclear use. Rather, Arihant is yet another manifestation of India’s deterrent dilemma between China and Pakistan. As Pakistan responds to India’s sea-based deterrent, it will exacerbate the subcontinent’s nuclear tensions while providing no meaningful change in India’s nuclear deterrent vis-à-vis Beijing in the foreseeable future.

Deterrence Stability and Crisis Stability: The Search for Equilibrium

Against China, India’s objective is to achieve deterrence stability: a true second-strike capability that insulates its nuclear arsenal against the risk of a Chinese first strike. Much of India’s technological force development in the post-1998 period has been motivated by the desire to decrease nuclear asymmetry with China. With Pakistan, the situation is almost the opposite: Pakistan cannot threaten India with nuclear annihilation without getting annihilated in return. Yet Pakistan’s strategy of employing sub-conventional conflict under the shadow of nuclear weapons has rendered Indo-Pakistani relations prone to crisis instability: the danger that a low-level crisis may escalate into an inadvertent use of nuclear weapons.

These factors create a “Goldilocks dilemma” for India: Its attempts to boost deterrence stability with China endanger crisis stability with Pakistan. China’s and Pakistan’s reactions to Arihant’s first deterrent patrol were illustrative of this dynamic. China hardly raised an eyebrow because unless India fields a credible SSBN force capable of launching ICBMs that can strike deep inside Chinese territory, it has nothing to fear. Pakistan, on the other hand, was quick to suggest that Arihant dilutes its nuclear deterrent and that it will opt for “cost-effective options” to maintain strategic stability. As Pakistan’s Foreign Ministry claimed, “no one should be in doubt about Pakistan’s resolve and capabilities to meet the challenges posed by the latest developments both in the nuclear and conventional realms in South Asia.” Recent statements by high-level Indian officials calling for elimination of Pakistan’s nuclear weapons through preemptive use of nuclear and conventional forces have only worsened Islamabad’s nuclear nightmares.

How can India achieve a balance between these two strategic imperatives? Regarding China, India should set some limits on what it considers a credible nuclear deterrent, rather than pursuing open-ended nuclear force development. As Rajesh Basrur has argued, India’s deterrent should not be based solely on establishing a credible response; it should also take into account an adversary’s appetite for risk. A limited capability should be sufficient to deter Beijing. India has exhibited such restraint in the past: After China tested nuclear weapons in 1964, Indian decision-makers were convinced that any Chinese nuclear threat or use against India would risk nuclear retaliation from the great powers and that this “minimal risk” was sufficient to deter Chinese decision-makers. Today, Beijing could facilitate a similar rethinking by accepting India as a nuclear power (the current policy of non-acknowledgment may spur India to continue its buildup in order to be taken more seriously) and initiating nuclear confidence-building measures.

Crisis stability will be harder, because for Pakistan, nuclear weapons provide not only a deterrent, or “shield” against India’s nuclear capability, but also a “sword” that permits it to continue fomenting sub-conventional war on the subcontinent.

To increase stability, India should publicly reaffirm its policy of no first use and adopt a retaliation-only nuclear posture, particularly since prominent voices in India’s strategic community have questioned these principles in the recent past. It should clarify that it has no intentions to use its nuclear forces in a preemptive mode. One Strategic Forces Command official told me that Arihant will only be used for countervalue strikes — that is, retaliatory strikes against Pakistani cities. Such declarations ought to be made at the highest levels of the Indian government. Arihant’s job — and, for that matter, the job of India’s entire nuclear arsenal — is to not create “fearlessness” in the Indian mind, as Modi’s office claimed. Rather, it is to ensure that India’s nuclear adversaries fear the consequences of their actions. A nuclear dialogue with Pakistan should therefore be reopened and shielded from the vagaries of domestic politics.

The nuclear competition between China, India, and Pakistan is a classic case of a triangular security dilemma. As India pursues deterrence stability vis-à-vis one adversary, it makes another adversary feel increasingly vulnerable. In theory, India could arrest this cascade through tailored deterrence: by employing specific nuclear capabilities against each of the two adversaries. In fact, in the conventional domain, India’s military posture towards China and Pakistan has long attempted such balancing. After the Sino-Indian border war of 1962, for instance, India erected 10 mountain divisions to deter the Chinese on the Himalayan frontier, but promised never to employ them on the Pakistani front.

Such tailored deterrence, however, is impossible to achieve in the subcontinent’s nuclear domain. First, compared to conventional forces, developing a variety of nuclear forces is extremely costly, particularly for states with pressing development needs. Second, tailored deterrence is difficult to attain at low numbers of nuclear weapons where the survivability of the arsenal is harder to guarantee. Last, increasing cooperation between China and Pakistan could leave India vulnerable to their combined nuclear might.

Developing robust deterrence against China will continue to drive India’s nuclear trajectory, as it has for years, but Pakistani reactions will make the ride extremely bumpy.


Yogesh Joshi is a Stanton Nuclear Security Postdoctoral Fellow at the Center for International Security and Cooperation, Stanford University. He is the coauthor of India and Nuclear Asia: Forces, Doctrine and Dangers (Georgetown University Press, 2018).

Image: All India Radio News