Previous Year Question
Which one of the following statements best reflects the idea behind the ‘Fractional Orbital Bombardment System’ often talked about in media?
A hypersonic missile is launched into space to counter the asteroid approaching the Earth and explode it in space.
A spacecraft lands on another planet after making several orbital motions.
A missile is put into a stable orbit around the Earth and deorbits over a target on the Earth.
A spacecraft moves along a comet with the same speed and places a probe on its surface.
Correct Answer: C
Detailed Solution
A Fractional Orbital Bombardment System, or FOBS, is a strategic weapon-delivery concept. In this system, a warhead is sent into a low-altitude orbital trajectory around the Earth, but it deorbits and proceeds towards a designated terrestrial target before completing an entire revolution around the Earth. It is named after this incomplete or fractional orbit.
A conventional Intercontinental Ballistic Missile generally follows a predictable ballistic arc. In contrast, a FOBS can approach a target from a different direction, making it more difficult during the initial stages of launch to estimate its actual target and impact trajectory.
A FOBS can be directed through a region where an adversary’s early-warning radars and missile-defence systems have comparatively limited coverage. A low-Earth trajectory and deorbit manoeuvre can reduce warning time. If combined with a hypersonic glide vehicle, the vehicle may manoeuvre after atmospheric re-entry, making interception even more difficult.
Option (a) relates to planetary defence, under which an attempt is made to alter the trajectory of or destroy an asteroid moving towards the Earth. Option (b) describes an interplanetary mission, while option (d) describes a comet-rendezvous and probe-landing mission. They are not related to FOBS.
The Outer Space Treaty prohibits placing nuclear weapons or other weapons of mass destruction in orbit around the Earth. Therefore, the development of orbital weapon systems raises serious questions relating to space security, arms control and strategic stability.