China in August tested a nuclear-capable hypersonic glide vehicle that circled the globe before speeding towards its target.
What is a Hypersonic Glide Vehicle that China tested?
- HGV is nuclear capable missile, which circled the earth before moving towards its target, missing it by two dozen miles.
- It is launched by a rocket which moves in the Earth’s lower orbit, at more than five times to 25 times the speed of sound.
- The vehicle is capable of carrying nuclear payloads, which gives the launching country the strategic capacity to attack almost any target across the world.
Hypersonic Speed and Technology:
- Hypersonic speeds are 5 or more times the Mach or speed of sound.
- It describes an aircraft’s speed compared with the speed of sound in air, with Mach 1 equating to the speed of sound i.e. 343 metre per second.
- Hypersonic cruise missiles: These are the ones that use rocket or jet propellant through their flight and are regarded as being just faster versions of existing cruise missiles.
- Hypersonic Glide Vehicle (HGV): These missiles first go up into the atmosphere on a conventional rocket before being launched towards their target
- Technology Used: Most hypersonic vehicles primarily use the scramjet technology, which is a type of Air Breathing propulsion System.
- This is extremely complex technology, which also needs to be able to handle high temperatures, making the hypersonic systems extremely costly.
How is HGV different from an ICBM?
- A hypersonic glide vehicle orbits the earth at a lower height, and is manoeuvrable as compared to ICBM.
- The ability to change track or target, mid-trajectory, along with the speed, makes them tougher to track and defend against.
- The manoeuvrability provides them in-flight updates to attack a different target than originally planned.
- They possess ability to fly at unpredictable trajectories, these missiles will hold extremely large areas at risk throughout much of their flights.
Which countries have hypersonic technology?
- Apart from China, the US and Russia are working on the technology.
- France and India are working together for gaining the capability.
Classification of Missiles Based on Speed
|Velocity in m/s
Implications for India:
- Hypersonic technology developments, in the backdrop of growing US-China rivalry and a year-long standoff with Indian forces in eastern Ladakh, is certainly a threat for India’s space assets along with the surface assets.
- The offence system operating at these speeds would mean a requirement to develop defence systems at these speeds.
Development of Hypersonic Technology in India:
- India, too, is working on hypersonic technologies.
- As far as space assets are concerned, India has already proved its capabilities through the test of ASAT under Mission Shakti.
- Hypersonic technology has been developed and tested by both DRDO and ISRO.
- Recently, DRDO has successfully flight-tested the Hypersonic Technology Demonstrator Vehicle (HSTDV), with a capability to travel at 6 times the speed of sound.
- Also, a Hypersonic Wind Tunnel (HWT) test facility of the DRDO was inaugurated in Hyderabad. It is a pressure vacuum-driven, enclosed free jet facility that simulates Mach 5 to 12.
Air Breathing Propulsion System
- About: These systems use atmospheric oxygen, which is available up to about 50 km of earth’s surface to burn the fuel stored on-board thereby making the system much lighter, more efficient and cost effective.
- Examples of Air Breathing Propulsion System include the Ramjet, Scramjet, Dual Mode Ramjet (DMRJ).
- A ramjet is a form of air breathing jet engine that uses the vehicle’s forward motion to compress incoming air for combustion without an axial compressor.
- Fuel is injected in the combustion chamber where it mixes with the hot compressed air and ignites.
- Ramjets cannot produce thrust at zero airspeed; they cannot move an aircraft from a standstill.
- A ramjet-powered vehicle, therefore, requires an assisted take-off, like a rocket assist, to accelerate it to a speed where it begins to produce thrust.
- The ramjet works best at supersonic speeds and as the speed enters the hypersonic range, its efficiency starts to drop.
- A scramjet engine is an improvement over the ramjet engine as it operates at hypersonic speeds and allows supersonic combustion, which gives it its name — supersonic combustion ramjet, or scramjet.
- The scramjet is composed of three basic components:
- A converging inlet where incoming air is compressed,
- A combustor where gaseous fuel is burned with atmospheric oxygen to produce heat,
- A diverging nozzle where the heated air is accelerated to produce thrust. The exhaust gases are accelerated to hypersonic speeds using a divergent nozzle.
- The speed at which the vehicle moves through the atmosphere causes the air to compress within the inlet. As such, no moving parts are needed in a scramjet, which reduces the weight and the number of failure points in the engine.
- Dual Mode Ramjet (DMRJ):
- The third concept is a mix of ramjet and scramjet, which is called DMRJ.
- There is a need for an engine which can operate at both supersonic and hypersonic speeds.
- A DMRJ is an engine design where a ramjet transforms into a scramjet over Mach 4-8 range, which means, it can operate in both the subsonic and supersonic combustor mode.
Source: Indian Express