SRIHARIKOTA: India on Sunday became the fourth country to successfully test launch a scramjet engine, The Hindu reported.

The test flight, which represents a milestone in the ISRO's efforts regarding its future space transportation system, took place at the Sathish Dhawan Space Centre launch pad.

The purpose of the Indian Space Research Organisation's (ISRO) experimental mission is the realisation of an Air-Breathing Propulsion System that utilises hydrogen fuel and oxygen from the atmosphere as an oxidiser.

The scramjet engines help reduce launch costs by cutting down on the amount of oxidiser which needs to be carried along with the fuel.

An ISRO official told Indian news agency IANS that the two air-breathing engines hugging an Advanced Technology Vehicle rocket normally start breathing air when the rocket reaches a height of 11 kilometres.

The ISRO said, "With this flight, critical technologies such as ignition of air-breathing engines at supersonic speed, holding the flame at supersonic speed, air intake mechanism and fuel injection systems have been successfully demonstrated."