by Brig Kuldip Singh (Retd)

On 29 August, the Indian Navy commissioned into service the 6,000-ton INS Arighat, the second Arihant-class SSBN (Ship Submersible Ballistic Nuclear, meaning, a nuclear-powered, ballistic missile carrying submarine).

Speaking at the commissioning ceremony at the Ship Building Centre, Visakhapatnam, Defence Minister Rajnath Singh stated that ‘Arighat’ would further strengthen India's three-tier retaliatory nuclear deterrent capability. As per the Ministry of Defence (MoD), the “technological advancements undertaken indigenously on Arighat make it significantly more advanced than its predecessor Arihant.”

Earlier, on 5 November 2018, while announcing the successful completion of the first deterrence patrol by INS Arihant (India’s first SSBN), Prime Minister Narendra Modi stated, “… a credible nuclear deterrence is the need of the hour. The success of INS Arihant gives a fitting response to those who indulge in nuclear blackmail.” A press release from the PMO further stated that the deployment of the INS Arihant completed “the country’s survivable nuclear triad”.

With the induction of ‘Arihant’ into the Indian Navy, India became the sixth country in the world to build and operate an SSBN – which is a momentous achievement.

There is a need, however, to assess whether the two SSBNs can be deemed a “credible sea-based strategic deterrence” or whether these are the incremental steps towards operationalising a full-fledged sea leg of the nuclear ‘triad’.

India’s SSBN Program

INS Arihant’s precursor program, the Advanced Technology Vessel (ATV), was initiated in 1974, with the first submarine being codenamed ‘S2’.

In February 2009, after decades of sustained, synergistic efforts between the Indian Navy, the DRDO, the BARC, selected PSUs and the private industry, the MoD confirmed the ATV project was in the final stages.

On 26 July 2009, INS Arihant was launched at Visakhapatnam in a quiet ceremony by Smt Gursharan Kaur, wife of former Prime Minister Manmohan Singh.

The former prime minister congratulated the ATV team for overcoming several hurdles to help India acquire self-reliance in the field of advanced defence technology while making a special mention of the cooperation extended by Russia. Many foreign analysts and the media speculated that the Arihant was based on the Russian Borei-class SSBN (which is bigger than the Arihant). Some claimed that it was “similar to the Soviet Charlie II-class, detailed drawings of which were obtained from the Soviet Union in 1989”.

The construction of the second SSBN of the Arihant-class, INS Arighat, commenced in 2009, and it was launched in November 2017. The Arihant-class is presently equipped with 10-12 B-05/K-15 nuclear weapon-tipped Submarine Launched Ballistic Missiles (SLBM) [range 750 km] for launch through four vertical tubes. However, both are expected to be soon kitted with the K-4, a 3,500-km range SLBM, and eventually, the K-5 (range 5,000 km).

SSBNs are the ultimate representation of nuclear strike-force readiness and credible strategic deterrence.

India’s third SSBN, the INS Aridhaman or S4, which would displace about 1,000 tons more than the Arihant-class, is expected to be commissioned next year, and will be followed by the S4 'Star'. Both will be equipped with the K-4 SLBM and likely to be based at a new naval facility, INS Varsha, Rambilli (near Vishakhapatnam).

Additionally, a new class of SSBNs, the S5, is under development. Displacing about 13,500 tons, these will be equipped with the K-6 SLBM, also under development, which is a three-stage, solid-fueled SLBM capable of carrying a MIRV (Multiple Independently-targetable Re-entry Vehicle) warheads with a range of 6,000 km.

In addition to SSBNs, plans also exist to progressively build six nuclear-powered attack submarines (Ship Submersible Nuclear, or SSNs).

No First Use Policy

In contemporary nuclear strategy, the policies of 'First Use' and 'No First Use' are largely a derivative of a nation’s threat perception, conventional military strength and symmetry vis-à-vis adversarial nations, its Comprehensive National Power, core national interests, its nuclear weapons arsenal, the means of delivery available, the command and control structure, its survivability, and geo-political circumstances.

Nations that are militarily weak but possess nuclear weapons usually tend to project an ambiguous First Use policy. The aim is to “draw a line in the sand” although it is hardly an assured defence as history shows (China against the US in Korea in 1950; the 1973 Egyptian and Syrian attack on Israel; India against Pakistan in Kargil 1999).

On the other hand, a No First Use pledge, which is a self-declared confidence-building measure (CBM), that can be unconditional or provided with certain conditions, is premised around some sort of a second-strike capability. This assumes that the No First Use-espousing nation will survive a first strike and retain sufficient warheads and delivery vectors to launch massive retaliation.

As long as a country can safeguard its second-strike capability, it can maintain a No First Use posture. Notably, a credible second-strike capability also plays a big role in deterring a first strike.

A nation with a superior conventional military does not need a First Use nuclear policy because if it chooses First Use for nuclear weapons, any nuclear retaliation by the adversary will cause far more damage than any conventional counter-strikes can. There is, thus, a good case for a No First Use policy since it can

Prevent nuclear war whose escalation ladder many experts feel cannot be easily controlled
Strengthen the non-proliferation regime
Promote strategic stability while allowing scope for operations by conventional forces

SSBNs And Deterrence

Since SSBNs are immensely hard to detect and track, and when mated with nuclear warhead-tipped ballistic missiles, they are the ultimate representation of nuclear strike-force readiness and credible strategic deterrence since they provide both a first-strike and a second-strike option.

The first strike can be used for disarming an adversary’s nuclear arsenal or against ‘value’ targets. For the No First Use countries, SSBNs provide an excellent deterrence (second-strike) option to prevent a conventional conflict from escalating into a nuclear exchange.

A second-strike capability is ideally based around SSBNs, but could also be achieved through rail-mobile/road-mobile ICBMs as these too can be moved around and hidden. Presently, even with its land-based nuclear arsenal, India enjoys a de-facto second strike capability against Pakistan as the latter’s nuclear-tipped ballistic and cruise missiles cannot cover the entire Indian subcontinent, and consequently, cannot target India’s entire land-based nuclear arsenal in a first strike.

As far as China is concerned, the recent induction of the sealed-canister-launched, solid-fuelled, road-mobile Agni-V ICBM (range 5,000 km plus) allows India to cover the entire Chinese mainland including the eastern coast

There are two broad models for posturing SSBN-based strategic deterrence - a ‘continuous at-sea’ presence and the ‘bastion’ model.

The ‘continuous at-sea’ model is ideal for maintaining credible strategic deterrence. This requires at least one submarine armed with nuclear weapons always deployed underwater. The same model of deterrence in the case of smaller Western nations like the UK and France envisions at least three to four SSBNs, with one being on patrol at any time.

The other option is the ‘bastion’ model employed by the USSR during the latter half of the Cold War. This envisions SSBNs confined to, and operating in, home waters, only to slip away just before hostilities. There is always the danger of them being tracked down when they deploy from known ‘bastion’ locations.

It would, thus, be evident that India cannot maintain a ‘continuous-at-sea’ presence with two SSBNs. Besides, both the Arihant and the Arighat are presently equipped with a 750-km range missile. To hit some of its targets, the Arihant will have to get close to adversarial shores – where it could be detected and targeted. Until an SLBM with a longer range is available and more SSBNs are fielded, the Arihant and the Arighat will, in all probability, use the ‘bastion’ model for basing.

For India, with its No First Use policy, an SSBN-based strategic deterrence is imperative. Locations of a land-based arsenal can be progressively discerned by adversarial powers, increasing the temptation for a first strike.

A sea-based second-strike capability, however, discourages such adventurism. The building of SSBNs is, therefore, a stupendous achievement, and the conduct of deterrent patrols by them is an even greater one.

With the induction next year of INS Aridhaman, equipped with the longer-range K-4 SLBMs, India would be able to maintain a ‘continuous-at-sea’ presence and thereby operationalise a full-fledged sea-based second-strike capability.

Kuldip Singh is a retired Brigadier from the Indian Army. This piece from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style and length. This portal does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s)