CHENNAI (TIP): Indian Space Research Organisation (Isro) has successfully tested two `air breathing’ scramjet engines as the first step to perfect a futuristic technology to launch missiles, inject heavier satellites in orbit, and fly astronauts at hypersonic speed. If fitted to a spaceplane, the engine can cut down inter-continental travel time and fly people in just an hour across the globe to New York.
The engine, which use oxygen from the atmosphere to provide propulsion along with Hydrogen stored in the rocket, was developed at Rs 35crore. During the five minute test on Sunday, the scramjet engine auto-ignited and burned fuel for five seconds at an altitude of 20km after taking off on two RH-560 (Rohini) sounding rockets at Satish Dhawan Space Centre, Sriharikota. Vikram Sarabhai Space Centre (VSSC) director K Sivan said, “We have got good results. It is only a baby step, but an important step, towards developing the full fledged technology. We need to determine what should be our next step, to demonstrate which aspect of the technology”.
It will take up to three decades and more test flights to have a fully developed scramjet engine in a launch vehicle. Scramjet engines are different from conventional rocket engines that carry fuel (hydrogen) and oxidiser (oxygen) to propel a rocket. The hypersonic engine, with its air breathing propulsion system, would carry only liquid hydrogen as fuel and takes oxygen from the atmosphere which it touches supersonic speed to burn the fuel for propulsion. The engine, which will propel vehicles at hypersonic speed, will reduce rocket weight by half, increase its efficiency, cut down the cost and enable carrying heavier payload.
Isro will conduct a lot more experiments with the engine including tests at different speeds and fine-tuning use of new materials like Inconel (an alloy of nickel, chromium and iron) and a carbon-carbon composite. “Sunday’s test of autoigniting the scramjet engine was similar to lighting a match during a cyclone,” said Sivan. After the rocket reached an altitude of 7km, the first stage broke off and fell into the Bay of Bengal. When the second stage, to which two scramjet engines were fixed, auto-ignited, the rocket had reached 20km altitude at Mach 6 (7408.8kmph) and the flame sustained for five seconds, burning the fuel.
By successfully testing a twin-scramjet engine, India has joined an elite group of countries like US, Japan, China, Russia and Europe that has demonstrated the technology which can be used to make a spaceplane. Isro’s immediate plan, however, is not to make a spaceplane. It is looking to integrate the engine with a reusable launch vehicle which is under development. There is a plan to design and develop a new vehicle that may look like a plane for the engine as it cannot be used in existing launch vehicles. While scramjet technology is not a replacement for cryogenic engines and will only be a supplement, Isro is also looking to develop a technology using air-breathing propulsion system where the air flow into the engine is compressed, converted into liquid oxygen and stored for use as fuel by the rocket after it leaves the atmosphere.