Knowledge Nugget: What makes scramjet engines crucial for hypersonic missiles?
UPSC Current Affairs: India achieves a 1,200-second scramjet runtime in hypersonic cruise missile technology. What is this technology? How is it different from a ballistic missile? What is the difference between a scramjet and a ramjet? In 'Beyond the Nugget', also learn about the TARA system.
The hypersonic cruise missile uses an advanced active cooled scramjet combustor that incorporates an innovative flame stabilisation technique. Take a look at the essential concepts, terms, quotes, or phenomena every day and brush up your knowledge. Here’s your knowledge nugget on scramjet and hypersonic cruise missile for today.
Knowledge Nugget: Hypersonic Cruise Missile System and actively cooled scramjet full-scale combustor
Subject: Science and Technology
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Why in the news?
India on 9th May, achieved a major breakthrough in hypersonic missile technology. The Defence Research and Development Organisation (DRDO) accomplished a 1,200-second runtime of its actively cooled scramjet full-scale combustor. The test was conducted at the Scramjet Connect Pipe Test (SCPT) facility in Hyderabad, building on the successful 700-plus second test carried out in January.
Key takeaways:
1. It is a hypersonic cruise missile capable of exceeding five times the speed of sound, or over 6,100 km per hour, for extended periods. This was achieved through a cutting-edge supersonic air-breathing engine, which utilises indigenously developed liquid hydrocarbon endothermic fuel, high-temperature Thermal Barrier Coating (TBC) and advanced manufacturing processes.
2. The missile uses an advanced active cooled scramjet combustor that incorporates an innovative flame stabilisation technique that holds a continuous flame inside the combustor with an air speed of more than 1.5 km per second.
3. The TBC is jointly developed by Defence Research and Development Laboratory (DRDL) and Department of Science and Technology (DST) facilities. It is designed to withstand extreme temperatures encountered during hypersonic flight. A new advanced ceramic TBC having high thermal resistance and capable of operating beyond the melting point of steel.
What are Hypersonic missiles?
4. Hypersonic missiles travel at a speed Mach 5, or at least five times the speed of sound in the upper atmosphere.
5. The two types of hypersonic weapons systems are Hypersonic Glide Vehicles (HGVs) and Hypersonic Cruise Missiles (HCMs). HGVs are launched from a rocket before gliding to the intended target, while HCMs are powered by air-breathing high-speed engines or ‘scramjets’ after acquiring their target.
Cruise vs Ballistic missiles
6. Ballistic missiles use projectile motion to deliver warheads to a target. They are powered for a relatively brief time, after which they let the laws of physics take them to their target. These missiles are categorised based on range. Ballistic missiles can carry either nuclear or conventional warheads.
7. The manoeuvrability of the hypersonic cruise missile is what sets it apart from a ballistic missile. Unlike ballistic missiles, hypersonic missiles do not follow a ballistic trajectory and can be manoeuvred to the intended target.
8. The cruise missiles fly at a low distance from the ground while the ballistic missiles follow a parabolic trajectory. Ballistic missiles are easier to track since they have a standard parabolic trajectory, as compared to cruise missiles which can fix air defence systems due to their manoeuvrability.
Scramjet vs Ramjet
1. Air-breathing technology has potential to bring a significant shift in the launch vehicle design. According to ISRO, “Ramjet, Scramjet and Dual Mode Ramjet (DMRJ) are the three concepts of air-breathing engines which are being developed by various space agencies.”
2. In ramjet air-breathing jet engines, the vehicle uses the forward motion to compress incoming air for combustion without a rotating compressor. Fuel is injected in the combustion chamber where it mixes with the hot compressed air and ignites. It requires an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust.
3. “Ramjets work most efficiently at supersonic speeds around Mach 3 (three times the speed of sound) and can operate up to speeds of Mach 6. However, the ramjet efficiency starts to drop when the vehicle reaches hypersonic speeds,” as per ISRO.
4. A Supersonic Combustion Ramjet or Scramjet, is an improved version of ramjet engines as it efficiently operates at hypersonic speeds and allows supersonic combustion. In this, air gets sucked in from the front, fuel burns in the middle and exhaust gas comes out of the back generating thrust.
5. In a dual-mode ramjet (DMRJ), the jet engine transforms into scramjet over Mach 4-8 range, which means it can efficiently operate both in subsonic and supersonic combustor modes.
BEYOND THE NUGGET: Tactical Advanced Range Augmentation (TARA) system
1. The Defence Research and Development Organisation (DRDO) and the Indian Air Force (IAF) on May 7 successfully carried out the first flight trial of TARA system that can transform an unguided missile into a guided one.
2. The TARA glide weapon system is primarily a modular kit that can be attached to a conventional unguided warhead. It helps the missile glide over long distances, and accurately strike a target.
3. The system is believed to use a combination of inertial navigation and satellite-based positioning to steer the missile towards the target.
4. The TARA system glides, rather than relying on a rocket motor. This makes it lightweight and cost-effective while still extending the missile’s range.
5. Unguided bombs, which are referred to as gravity bombs or dumb bombs, can thus be upgraded to smart bombs, or precision-guided munitions, with relatively low effort. This can reduce the need to develop entirely new missile systems.
Post Read Questions
(1) Consider the following statements:
1. A Scramjet engine uses atmospheric oxygen for combustion and operates efficiently at hypersonic speeds.
2. Ramjet air-breathing jet engines work at a subsonic speed.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
(Answer: Statement 2 is incorrect because Ramjet works at a supersonic speed.)
(2) Consider the following statements: (UPSC CSE, 2023)
1. Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight.
2. 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?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
| Answer key |
| 1. (a) 2. (d) |
(Sources: Fit it, fire it: How an attachable system can help air missiles fly longer, strike better, ISRO scramjet engine test, India achieves 1,200-sec scramjet runtime in hypersonic missile technology push, ISRO, http://www.grc.nasa)
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