Why ISRO’s Scramjet Engines are ‘The Need of the hour’ ?


From the MARS Orbiter mission (Mangalyaan) to the recent successful Flight Testing of domestically designed Scramjet Engine, we have come a long way in the field of space research. We have seen undeterred success in the satellite launches using the Polar Satellite Launch Vehicle(PSLV) till date.

Why Scramjet Engines are ‘The Need of the hour’ ?

To understand Scramjet let us travel back in history, when the term ‘Jet Engines’ was the buzzword. One biggest advantage of a Jet Engine is that it can be used to take off from the runway. Jet Engines can take us up to MACH 3.5, that is 3.5 times the speed of sound (1Km/s). So a Jet Engine cannot take us into the Hyper-sonic regime which is about MACH 5. The main limitation in the Jet Engine is that the speed of flow that passes through the COMBUSTION chamber is very much Sub-Sonic. A Jet Engine primarily consist of 4 blocks. First is the Intake, followed by the Compressor, then comes the Combustion chamber  finally the Exhaust. The role of the compressor in a Jet Engine is to raise the level of Pressure and Temperature. But when we are operating at very higher speeds, the Intake and the Compressor has to reduce the flow to sub-sonic levels to facilitate the Combustion chamber. This process of slowing down generates a great amount of Pressure and Temperature, high enough to facilitate the combustion. So the role of Compressor and Turbine(that drives the compressor) becomes futile.

When you discard Compressor and Turbine in a Jet Engine, you end up with a Ramjet. A Ramjet Engine needs the air to to be pushed into its intake at Super Sonic, which then is reduced to Sub Sonic levels. But the act of pushing air into the Ramjet (called RAM-effect) increases the temperature to higher levels. At that point of time, we needed a Jet Engine which can keep the speed of flow at Super Sonic levels even inside the engine and also weigh less(without compressor, turbine and other mechanical overheads). Thus a Scramjet was developed. The oxygen needed by the Scramjet Engine for combustion is taken from the atmosphere passing through the vehicle, instead of from a tank on-board unlike the previous systems. This makes the craft lighter and faster.

The Scramjet technology significantly cuts down the cost of launching rockets by reducing its weight by more than half. On July 30, 2002, the University of Queensland’s HyShot team and international partners conducted the first ever successful test flight of a Scramjet. Though 14 years looks like a long period, but for a country with an economy like us, this is a phenomenal achievement. The Hyshot team had funding across the globe but Hyshot 1 failed miserably. But in a jiffy,we have come an inch closer in establishing a reusable space transport system for every future mission of ours. This is what, that makes ISRO stand tall in the Space Race– A low-cost, indigenous and a successful Scramjet mission in the very first attempt.

Duly quoting….

This test-bed could be a pathfinder for a future unmanned reusable launch vehicle that could take off like a rocket, deploy a satellite in orbit, and return to Earth and land on a runway. ”


Following the Scramjet, ISRO is all set for revolutionary missions in the next 10 years. That includes India’s first manned mission into moon, the Chandraayan 2; the SAARC satellite, a communication cum meteorology satellite which is regarded as the Brainchild of Mr.Narendra Modi; Aditya 1, the first Indian mission to study the sun; NISAR mission, the biggest collaboration of all time between two key players in Space Research-  NASA and ISRO. ISRO’s budget for a fiscal year is just 3 percent of the NASA’s budget. So it cannot and should not be seen as a competition. ISRO is already a key player in the field of Space Exploration and with the years to come, ISRO will be regarded in the same way as that of NASA.