- K-4 (Submarine-Launched Ballistic Missile) is an indigenously developed, nuclear-capable Intermediate-Range Ballistic Missile by the Defence Research and Development Organisation (DRDO).
- It provides the sea-based leg of India’s Nuclear Triad (Land, Air, Sea), ensuring credible second-strike capability under India’s No First Use (NFU) doctrine.
- December 2025
Successful user trial from an operational SSBN (Ship Submersible Ballistic Nuclear), INS Arighaat, in the Bay of Bengal.
Confirms final validation before induction (earlier tests used pontoons). - Key specifications
Range ~3,500 km
Two-stage, solid-fuel propulsion
Nuclear / conventional payload up to ~2,000 kg
Guidance via INS + NavIC - Platform linkage
Designed for Arihant-class SSBNs
INS Arihant mainly uses K-15 (Sagarika)
INS Arighaat and INS Aridhaman are K-4 capable
