Isro’s Scramjet a big success, to cut cost of rocket launch

In its first step towards realising its own air-breathing propulsion system, Isro on Sunday successfully tested Scramjet, an engine that takes atmospheric oxygen to burn engine fuel. The two-stage RH-560 sounding rocket with twin Scramjet engines successfully took off from the Satish Dhawan Space Centre in Sriharikota at 6 am. After a flight of around 300 seconds, the vehicle touched down in the Bay of Bengal, approximately 320 km from Sriharikota. Isro chairman A.S. Kiran Kumar said: “The test was very successful and more tests need to be carried out before it is made operational.”

India has become the fourth country/entity after the United States, Russia and the European Space Agency to have successfully tested the Scramjet engine. “The Scramjet experiment was conducted for 5 seconds between 55 and 60 seconds of the flight at 20 km height. The results are showing the test was gone as exactly as we predicted,” said K. Sivan, director of the Vikram Sarabhai Space Centre.

The Scramjet engine designed by Isro uses hydrogen as fuel and oxygen from the atmospheric air as the oxidiser. “At the beginning, the engine was opened to inject the fuel. The Scramjet engine was ignited automatically. The injection of fuel lasted for seven seconds and all the duration the flame sustained at the supersonic speed,” he explained.

“The results showed we achieved the required thrust level. With this experiment, Isro and India can achieve very crucial and critical, complex technology which is useful for space transportation system,” he said.

The Scramjet is expected to bring down rocket launch costs by reducing the amount of oxidiser need to be carried with the fuel. For example, the GSLV rocket’s weight is 400 tonnes, half of which is the oxidiser, that will burn within a height of 50 km. “If we take oxygen from the atmosphere, the rocket’s weight will be reduced, efficiency will be increased as it can carry heavier payloads,” Mr Sivan said.

Mr Sivan warned, however, that the development of the Scramjet engine will not happen in the near future, and will take more than a decade. Speaking to reporters in Chennai after the successful flight test, he said: “It is a first baby step towards achieving future rocket technology. This technology is very important for the future as it will give major advancements in the space transportation system.”

He said the Scramjet engine’s success was an important milestone in space technology for India. Terming the new technology a “holy grail” for space-faring nations, he said: “This is an emerging technology and very few countries alone have demonstrated it.” Mr Sivan added: “We have tested it at Mach 6 speed. We have to test this engine at various speeds, from Mach 2 to 12. We also need to develop new materials for the engine as it has to withstand the oscillation of rockets.”

The total cost of the project will be around Rs 35 crores, while Sunday’s experiment cost Rs 3 crores.

What next The Scramjet engine to undergo various tests for next few years before it becomes operational

How will it reduce the weight of the rocket In a 400-tonne GSLV vehicle, 85% is rocket propellants. 70% of the propellants are oxidizers which will be used to burn the fuel. Most of these oxidizers will be consumed within the 50 km height. The Scramjet engine will use the atmospheric oxygen as an oxidizer in the combustion process and the weight of the rocket at the liftoff stage can be reduced up to 50 per cent. This will reduce the cost of the launches as well.