ISRO Recently Completes Another Series Tests of Its Scramjet Engine

Space News ,India :- ISRO has recently concluded another phase of testing for its Scramjet engine, marking a significant milestone in the development of air-breathing propulsion technology. In an earlier phase, the engine was tested with Hydrogen as fuel, and the recent tests involved the use of Kerosene (Isroscene) as fuel. This shift to Kerosene is notable for its ability to reduce overall volume, making it more suitable for extended-duration flights.

Presently, satellite launch vehicles are typically expendable, designed for one-time use. These vehicles carry both fuel and oxidizer for combustion, resulting in high costs and low efficiency, as they can only transport a small percentage of their lift-off mass to orbit. To address this, there is a global effort to reduce launch costs, and one key focus is on developing next-generation launch vehicles with air-breathing propulsion systems.

Approximately 70% of the propellant carried by current launch vehicles consists of oxidizer. Future launch vehicles need a propulsion system that can utilize atmospheric oxygen during flight, significantly reducing the total propellant required to place satellites in orbit. Additionally, making these vehicles reusable could further slash the cost of satellite launches.

The concept of a reusable launch vehicle combined with air-breathing propulsion is gaining traction as a promising approach to achieving routine and cost-effective access to space. The development of air-breathing engines, including Ramjet, Scramjet, and Dual Mode Ramjet (DMRJ), is a strategic focus for space agencies worldwide.

Ramjets utilize the vehicle forward motion to compress incoming air for combustion without a rotating compressor. They are most efficient at supersonic speeds but start to lose efficiency at hypersonic speeds. Scramjet engines, on the other hand, operate efficiently at hypersonic speeds, allowing supersonic combustion. The Dual Mode Ramjet (DMRJ) is a hybrid engine that transforms from a ramjet to a scramjet over a specific speed range, making it versatile for subsonic and supersonic combustor modes.

In a significant achievement for ISRO, the successful flight testing of its Scramjet Engine Technology Demonstrator took place on August 28, 2016. This marked a crucial step towards realizing an Air Breathing Propulsion System. The test involved the use of the Scramjet engine at hypersonic speeds, reaching Mach 6, with the engine designed to use Hydrogen as fuel and atmospheric oxygen as the oxidizer.

 The testing utilized ISRO Advanced Technology Vehicle (ATV), a two-stage spin-stabilized launcher with identical solid motors. The Scramjet engines were mounted on the second stage, and after reaching the desired conditions for engine start-up, they functioned for about 5 seconds.

ISRO successfully tackled various technological challenges during the development of the Scramjet engine, including designing a hypersonic engine air intake, developing a supersonic combustor, creating materials capable of withstanding high temperatures, simulating hypersonic flow with computational tools, ensuring engine performance across a wide range of flight speeds, managing thermal issues, and conducting extensive ground testing.

India achievement in demonstrating the flight testing of a Scramjet Engine positions it as the fourth country globally to accomplish this significant milestone.