Why this matters now
Arihant is tested for: completing India’s nuclear triad (Agni land + Mirage/Rafale air + Arihant sea); the Advanced Technology Vessel (ATV) programme 1985 origin; August 2016 commissioning at Visakhapatnam (kept secret for years); the K-15 (Sagarika) and K-4 SLBMs; INS Arighat 29 August 2024 commissioning; the Defence Strategic Programmes Office direct PM oversight; survivability for second-strike under No-First-Use doctrine.
History
| Year | Milestone |
|---|---|
| 1985 | Advanced Technology Vessel (ATV) project sanctioned — classified. |
| 1998-2009 | Reactor design + miniature 83 MW pressurised water reactor (PWR) development at BARC. |
| 26 July 2009 | Arihant launched by then-PM Manmohan Singh at Ship Building Centre, Visakhapatnam — on Kargil Vijay Diwas. |
| 10 Aug 2013 | Reactor went critical. |
| August 2016 | COMMISSIONED — secret ceremony 22 August 2016; announced later. India’s nuclear triad operational. |
| 5 Nov 2018 | First “Deterrence Patrol” completed (PM Modi statement: India operationalised nuclear triad). |
| 14 Oct 2022 | 1st successful K-15 test from Arihant (750 km range). |
| 19 Nov 2018 | 1st K-4 SLBM launch (3500 km range). |
| 29 August 2024 | INS ARIGHAT commissioned by Defence Min Rajnath Singh at Visakhapatnam — 2nd Arihant-class boat. |
| 2025 | INS Aridhaman (3rd boat, S-4) under construction. |
Specifications
- Displacement: 6,000 tonnes surface; 6,500 tonnes submerged.
- Length: 111 m; Beam: 11 m.
- Propulsion: 1 × 83 MW pressurised water reactor (PWR) using highly-enriched uranium (HEU 30-40%) + 1 7-blade propeller.
- Speed: 12-15 knots surface, 24 knots submerged.
- Diving depth: 300 m.
- Range: Unlimited (nuclear reactor) — limited only by crew endurance + food.
- Armament: 4 vertical launch tubes — can fire 12 K-15 (Sagarika) SLBMs of 750 km range OR 4 K-4 SLBMs of 3500 km range. Also 6 torpedo tubes for 533mm torpedoes.
- Crew: 95-100.
K-15 + K-4 SLBMs
K-15 (Sagarika): India’s 1st SLBM. Range 750 km, 1-tonne nuclear warhead. 1st underwater test 27 January 2013 (Visakhapatnam pontoon). 1st test from INS Arihant 14 October 2022. Developed by DRDO from 1991. Operational on Arihant. Range adequate against Pakistan but not most of China.
K-4: Larger 3500 km SLBM — reaches all of China. 1st test 24 March 2014. Most recent successful test from Arihant 19 November 2018. Length 12 m, 2-tonne payload. Operational on Arihant + Arighat. K-5 (5000 km, MIRV) and K-6 (8000 km, MIRV) under development — matching Agni-V land-based capabilities for sea-leg.
UPSC angle
Know ARIHANT CLASS — India’s 1ST INDIGENOUS NUCLEAR-POWERED BALLISTIC MISSILE SUBMARINE (SSBN); ATV (Advanced Technology Vessel) project sanctioned 1985 classified; 83 MW PRESSURISED WATER REACTOR HEU 30-40% BARC; INS ARIHANT launched 26 July 2009 by PM Manmohan Singh on Kargil Vijay Diwas at Ship Building Centre Visakhapatnam, reactor critical 10 Aug 2013, COMMISSIONED secret ceremony 22 AUGUST 2016 (India 6th country with NUCLEAR TRIAD); 1st Deterrence Patrol 5 Nov 2018 PM Modi announcement; INS ARIGHAT commissioned 29 AUGUST 2024 by Rajnath Singh Visakhapatnam; INS Aridhaman 3rd boat S-4 construction 2025; SPECS 6000-6500 tonnes, 111 m length, 83 MW PWR, 24 knots submerged, 300 m diving depth, unlimited range; 4 VLT can fire 12 K-15 SAGARIKA 750 km OR 4 K-4 3500 km; 6 torpedo tubes 533 mm; crew 95-100; K-15 SAGARIKA 750 km 1st underwater test 27 Jan 2013 1st from Arihant 14 Oct 2022; K-4 3500 km 1st test 24 March 2014 Arihant 19 Nov 2018; K-5 5000 km MIRV + K-6 8000 km MIRV development; Defence Strategic Programmes Office direct PM oversight; survivability for SECOND-STRIKE under NFU doctrine.
Frequently asked questions
When was INS Arihant commissioned?
In August 2016 (kept secret for years) at the Ship Building Centre, Visakhapatnam — making India the 6th country with a nuclear triad.
What is INS Arighat?
The 2nd Arihant-class SSBN — commissioned on 29 August 2024 by Defence Minister Rajnath Singh at Visakhapatnam.
What SLBMs do Arihant-class submarines carry?
12 K-15 (Sagarika, 750 km) OR 4 K-4 (3500 km) submarine-launched ballistic missiles via 4 vertical launch tubes.
What is the nuclear triad?
The capability to deliver nuclear weapons by land (Agni), air (Mirage-2000/Su-30/Rafale), and sea (Arihant SSBN K-family SLBMs). India operationalised in August 2016.