SCRAMJET
- ISRO successfully launched a rocket using an indigenously built SCRAMJET engine in August, 2016.
- The experimental mission is aimed at the realization of an Air Breathing Propulsion System which uses hydrogen as fuel and oxygen from the atmosphere as the oxidizer.
- The test flight attained six times the speed of sound (Mach 6).
- It was able to achieve ignition and maintain stable combustion even at such high velocity for about six seconds. A big technological achievement indeed.
- The air intake mechanism and fuel injection systems were also successfully demonstrated.
- As it relies on oxygen present in the atmosphere, the trajectories of SCRAMJET engine-powered rockets are vastly different from conventional ones- rockets with SCRAMJET engine should remain in the atmosphere for a longer period than normal rockets.
- SCRAMJET rockets climb to a certain altitude and remain in the atmosphere for as long as possible to achieve the required velocity.
- The engine is used only during the atmospheric phase of the rocket’s flight.
- They are highly inefficient at low speeds, with their efficiency increasing at supersonic speeds.
- It will take many years before a commercial rocket powered by this engine takes to the sky.
Challenges
- One challenge will be to test the engine at higher Mach speeds and prolong the period of combustion.
- Since the SCRAMJET comes into play only when the rocket goes beyond Mach 5, an engine that initially works at subsonic speed (as a ramjet) and later as a SCRAMJET has to be developed.
With this India has become the fourth country to demonstrate the flight testing of SCRAMJET engines.
AVATAR
- ISRO also has plans to use the new technology for it’s Avatar programme
- Avatar, or ISRO’s reusable launch vehicle platform, is a concept that is capable of carrying out satellite launches- takes off vertically and lands back on a runway.
- It is designed to use ramjets and scramjets for thrust. The two engines will be used in different stages of the flight- with ramjets used at lower speeds, scramjets at hypersonic speeds and cryogenic engines when the craft reaches the edge of the atmosphere.
- Using Avatar for satellite launches will cut down costs by half.
- ISRO currently uses rocket launch vehicles like the PSLV to deliver satellites into orbit.
- PSLVs are expendable, meaning that they can be used only once.
Read More: SCRAMJET and it’s benefits
