Why in news?

The Defence Research and Development Organisation (DRDO) successfully test-fired the Agni-Prime (Agni-P) missile from a rail-based mobile launcher.

This launch has placed India among a select group of nations — Russia, the US, China, and possibly North Korea — with the capability to launch long-range ballistic missiles from railway platforms using canisterised launch systems.

What’s in Today’s Article?

• Agni Series of Missiles
• Agni-P: The Next-Generation Upgrade to Agni-I
• Mobile Launch Platforms and India’s Second-Strike Capability
• Advantages of Rail-Based Missile Launchers
• Countries with Rail-Based Missile Technology

Agni Series of Missiles

• The Agni series is India’s family of nuclear-capable ballistic missiles, developed under the Integrated Guided Missile Development Programme (IGMDP) by the DRDO.
• They are a key element of India’s strategic deterrence capability.
• Agni-I (1989): A medium-range ballistic missile (MRBM) with a range of 700–1,000 km. It was India’s first in the series and is road- and rail-mobile.
• Agni-II (1999): A two-stage solid-fuel missile with a range of 2,000–3,000 km, capable of carrying nuclear warheads.
• Agni-III (2006): An intermediate-range ballistic missile (IRBM) with a range of 3,500–5,000 km, providing wider regional coverage.
• Agni-IV (2011): Improved navigation and accuracy, range of 3,500–4,000 km, lighter and more advanced than Agni-III.
• Agni-V (2012): An intercontinental ballistic missile (ICBM) with a range of 5,000–8,000 km, extending India’s deterrence to cover much of Asia and parts of Europe and Africa.
• Agni-P (Agni-Prime, 2021): A next-generation variant with a range of 1,000–2,000 km, combining advanced technologies from Agni-IV and V, lighter, more accurate, and canisterised.
• Agni-VI (under development): Expected range of 8,000–10,000 km, with potential multiple independently targetable re-entry vehicle (MIRV) capability.

Agni-P: The Next-Generation Upgrade to Agni-I

• India’s Agni missile series, developed since the late 1980s, began with the Agni-I medium range ballistic missile (700–1,000 km range) tested in 1989.
• While Agni-I remains in service, defence planners sought upgrades, leading to the development of Agni-P (Agni-Prime).
• Agni-P combines Agni-I’s range with advanced propulsion and navigation technologies from Agni-IV and Agni-V.
  • It is the sixth missile in the Agni series.
• Weighing 11,000 kg, it is a two-stage, solid-fuel missile with an operational range of 1,000–2,000 km, capable of carrying high explosive, thermobaric, or nuclear warheads.
• A nuclear-capable version tested in 2021 drew praise from the then Defence Minister, who said it would further bolster India’s Credible Deterrence capabilities.

Mobile Launch Platforms and India’s Second-Strike Capability

• Mobile launch systems are vital to a nation’s second-strike capability, enabling it to retaliate after a nuclear attack.
• For India, which follows a “no first use” nuclear doctrine, such survivability is critical.
• Advances in satellite imagery, missile accuracy, and sensing technologies have made stationary silos increasingly vulnerable.
• As noted by defence experts, silos face heightened risks from both conventional and nuclear strikes.
• To counter this, militaries rely on mobile launch platforms — submarines, aircraft, and road or rail-based launchers — which are harder to detect and more resilient in an all-out conflict.

Advantages of Rail-Based Missile Launchers

• Rail-based missile platforms offer distinct advantages over road or sea systems.
• While road-based launchers are constrained by road width and quality, India’s 70,000-km railway network enables nationwide mobility without major preparation.
• The numerous railway tunnels provide natural hiding spots, allowing launchers to evade enemy satellite surveillance and remain concealed until deployment.
• Compared to submarine-launched ballistic missiles (SLBMs), rail-based platforms are also cheaper to build and maintain, making them a more efficient and scalable option for strengthening strategic deterrence.

Countries with Rail-Based Missile Technology

• India’s recent test places it among a select group of nations with rail-based missile launch capability.
• The idea dates back to the Cold War, when both the US and USSR explored rail-mobile ICBMs.
• The US studied rail launchers for its Minuteman ICBMs in the 1950s and again planned Peacekeeper deployment in the 1980s, but abandoned both due to cost and the Soviet collapse.
• The Soviet Union successfully deployed the RT-23 Molodets rail-based ICBM system, later dismantled under the START Treaty.
  • Russia later considered reviving the concept with the Barguzin system but shelved it in favour of hypersonic missile development.
• In 2016, China reportedly tested a rail-mobile version of its DF-41 ICBM.
• North Korea has also tested rail-based short-range ballistic missiles (SRBMs), demonstrating their mobility and survivability.
• Experts note that rail-based missiles are a cheap, reliable option for enhancing nuclear force survivability, with Russia pioneering it, the US considering it, and North Korea actively pursuing it.