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Scramjet Engine : Significance

Significance of Scramjet Engine


  • Oxygen is as essential for the process of combustion as it is for the sustenance of life. Therefore a rocket, during its launch, needs to combine a combustion fuel with liquid oxygen to create the thrust needed for the take-off and flight.
  • However, if the need for liquid oxygen is taken away (by producing air-breathing technology), the spacecraft can be much lighter, hence cheaper to launch.
  • While conventional rocket engines need to carry both fuel and oxidizer on board for combustion to produce thrust, air-breathing rocket systems, on the other hand, uses the atmospheric oxygen from their surroundings and burn it with the stored on- board fuel.

 Ramjet, Scramjet and Dual Mode Ramjet (DMRJ) are the three concepts of air breathing engines which are being developed by various space agencies.

 A ramjet is a form of air-breathing jet engine that uses the vehicle’s forward motion to compress incoming air for combustion without a rotating compressor.

 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.

A dual mode ramjet (DMRJ) is a type of jet engine where a ramjet transforms into scramjet over Mach 4-8 range, which means it can efficiently operate both in subsonic and Supersonic combustor modes.

Scramjet engine

  1. A scramjet engine is an improvement over the ramjet engine as it efficiently operates at hypersonic speeds and allows supersonic combustion. Thus it is known as Supersonic Combustion Ramjet, or Scramjet.
  1. Scramjet engines obtain oxygen from the atmosphere by compressing the incoming air before combustion at hypersonic speed. It uses hydrogen as fuel and the oxygen from the atmospheric air as the oxidizer.
  1. When the rocket reaches a height of 11 km, the scramjet engines would start breathing air directly from the atmosphere.
  1. Scramjets are highly inefficient at low speeds. Their efficiency increases at supersonic speeds.


1. The spacecraft can be smaller or carry more payloads, making it a commercially viable option.

  1. Scramjet technology effectively cuts down the cost of launching rockets by reducing its weight by more than half.
  1. The engine, when fully developed, will eventually be used in Reusable Launch Vehicles or RLV’s.
  1. India has become the fourth country to successfully test the scramjet engine after United States, Russia and the European Space Agency. ISRO carried out successful testing of scramjet engine from the Satish Dhawan Space Centre, Sriharikota. ISRO’s Advanced Technology Vehicle (ATV), which is an advanced sounding rocket, was the solid rocket booster used for this recent test of Scramjet engines at supersonic conditions. The space agency’s ATV rocket was able to fly at Mach 6 (six times the speed of sound) speeds.

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  • Captain America

    India is the fourth country as ESA can’t be associated with any specific country, like ISRO or NASA..

  • Ubermensch

    Anyways most of the news reporters say fourth including ISRO chief.
    But should we consider ESA as country organisation in objective type questions for prelims?

  • Ubermensch

    Oh okay.
    This links says something else. Hence confusion.

    “The United States first successfully tested scramjet engines in July 2002. It was followed by Russia, European Agency, Japan and then China. Significantly, the Indian space agency achieved this feat in its maiden attempt.”

  • ManikChand

    India is the
    fourth country to demonstrate the flight testing of Scramjet Engine. The
    successful technology demonstration of air-breathing Scramjet engines in flight
    by ISRO today is a modest yet important milestone in its endeavour to design
    and develop advanced air breathing engines including engines for ISRO’s future
    space transportation system.


  • ForumIAS


  • Ubermensch

    I think India is the fifth country. United States first successfully tested scramjet engines in July 2002. It was followed by Russia, European Agency, Japan and then China. I read this on pib.

  • Captain America

    Got it.. thanks.. 🙂

  • ManikChand

    The significance is important. The entire story here can be written in just 2 lines when asked in achievements of ISRO and their applications.

  • Captain America

    Thanks.. 🙂 Only one question, as these technological advancements are dynamic in nature, is the topic important for mains 2017 ??