Nuclear-Capable Missiles of The South Asia

Whenever there is a surface-to-surface missile test in the South Asia (India and Pakistan), the news reports read, "Nuclear capable missile has been test fired". Some links are given here;

India tests nuclear capable missile with range as far as Beijing,
http://www.reuters.com/article/2013/09/15/us-india-missile-idUSBRE98E03L20130915
India Tests Nuclear-Capable Missile,
http://www.wsj.com/articles/india-tests-nuclear-capable-missile-1422719598

Few countries around the world openly possess nuclear weapons and they know well their working. These countries are USA, Russia, France, UK and China. The ballistic and cruise missiles with nuclear warheads that these countries built were designed from the very start to be armed with nuclear warheads. Accordingly the whole missile system and its launchers were designed to those specifications.

A nuclear-capable missile is itself a vague term. A missile is either conventional or nuclear. It is believed in the South Asia that a nuclear-capable missile is a conventional missile fitted with a nuclear warhead.  In reality, a conventional surface-to-surface missile (either ballistic or cruise) is highly unlikely to carry a nuclear warhead. As stated above, a missile armed with nuclear warhead is designed from the start to be so.

The electronics, sensors, electrical power supply, fusing, arming, triggering and other protection systems for nuclear missiles are different from those of the conventional ones. Therefore, it is not just by replacing the warhead that one can get a nuclear missile. The whole re-entry vehicle would need to be modified alongwith other design modifications.

This inattention to detail must have resulted from a lack of in-depth knowledge of the weapon systems. The military experts of the nuclear countries may even have ridiculed such statements with conclusions going very far.
Conventional warhead missiles (surface-to-surface) are mostly built with contact or inertia fuses which initiate the explosion upon hitting a target. Nuclear missiles on the other hand have radar or altimeter based fuses for explosion above the ground level (can be called as air burst).

To elaborate further, in addition to things stated above, a nuclear missile is supposed to be capable of delivering a second-strike. Second-strike means that one has already been hit by a nuclear weapon resulting in damaged infrastructure and facilities and yet one is still able to launch a retaliatory nuclear strike. If atmospheric nuclear blasts are carried out, they would generate electromagnetic pulses and all unprotected electronic systems would be highly perturbed.

This capability requires further modifications to the design of missile. These modifications include EMP (ElectroMagnetic Pulse)-protected electronics and navigation systems. Furthermore, NBC (Nuclear Biological and Chemical) protection needs to be given to the launcher and other support vehicles of the missile.

The ICBMs (Inter-Continental Ballistic Missiles) of all nuclear powers are exclusively armed with nuclear warheads because they were designed to be nuclear from the very inception. It is the case for both the ground-launched or the submarine-launched ballistic missiles. These countries do not have nuclear warheads that would fit on the conventional missiles.

Nuclear warheads fit on the missiles specifically designed for that purpose. This is the case of the French ASMP (Air-Sol Moyen Portée) and ASMP-A (Air-Sol Moyen Portée- Amelioré) nuclear cruise missiles.  ASMP-A is currenly carried by its dedicated aircraft, the nuclear derivative of the Mirage 2000, called Mirage-2000N. Before Mirage-2000N, French Air Force had a dedicated nuclear bomber (Mirage-IV) for the delivery of the nuclear bomb. Now the bomb has been replaced by the nuclear cruise missile ASMP-A. Similarly, the Royal Air Force (RAF) had deployed Blue Steel nuclear missile with its V-Bombers fleet during Cold War period. Even the B-29 bomber which delivered the first nuclear bombs over the Japan in the Second World War (year 1945) were given special modifications for that purpose. This proves that special avionics are required for delivery of nuclear weapons.

Yes a nuclear missile can be modified/simplified to carry a conventional warhead but the reverse is still unlikely. If a nuclear re-entry vehicle is designed for a conventional missile with all required modifications, it would become a nuclear derivative of that missile and it would be a separate system. This approach is illustrated in the BGM-109G Gryphon cruise missile of the USAF. It is externally similar to the conventional Tomahawk cruise missile but has specialized systems and dedicated electronics.

Therefore, the news item should either read, "Ballistic (or cruise) missile with a nuclear derivative test fired" or "Ballistic missile with a dummy nuclear warhead test fired".  The first statement would emphasize that it is a conventional missile but a nuclear derivative has also been built. The second statement would emphasize that it is a nuclear missile.