Previous Year Question
Consider the following statements:
Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight.
Agni-V is a medium-range supersonic cruise missile, while BrahMos is a solid-fuelled intercontinental ballistic missile.
Which of the statements given above is/are correct?
Only 1
Only 2
Both 1 and 2
Neither 1 nor 2
Correct Answer: D
Detailed Solution
Statement 1 is incorrect. It reverses the propulsion and flight characteristics of ballistic and cruise missiles.
A ballistic missile is accelerated to a very high speed by a rocket engine during its initial boost phase. After its fuel is exhausted or its engine shuts down, its warhead primarily follows a ballistic trajectory under the influence of gravity and momentum. Much of its path may lie in the upper atmosphere or beyond it, and its speed during re-entry may reach several Mach; therefore, describing it as a subsonic, jet-propelled missile throughout its flight is incorrect.
In contrast, a cruise missile flies within the atmosphere like an aircraft with the help of aerodynamic lift. Air-breathing engines such as turbojets, turbofans, ramjets or scramjets may provide its sustained propulsion. Cruise missiles may be subsonic, supersonic or hypersonic.
Statement 2 is incorrect. Agni-V is not a cruise missile but India’s long-range, surface-to-surface ballistic missile. It is a canisterised, three-stage, solid-propellant missile with a reported range exceeding 5,000 km. Its ballistic trajectory and long-range strategic role mean that it cannot be described as a medium-range supersonic cruise missile.
BrahMos is not an intercontinental ballistic missile but a supersonic cruise missile. Its first stage is a solid-propellant booster that accelerates the missile to supersonic speed. After the booster separates, a liquid-fuel ramjet engine in the second stage provides sustained supersonic flight.
BrahMos has been developed for launch from land-based mobile launchers, surface ships, submarine platforms and aircraft. It generally travels at approximately Mach 2.8–3 and can follow low-altitude and sea-skimming trajectories.