ISRO successfully test-fires Scramjet Rocket Engine

Indian Space Research Organisation (ISRO) successfully tested its own scramjet engines from Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh.

About Scramjet Engine:

A scramjet supersonic combusting ramjet is a variant of a ramjet air breathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to forcefully compress the incoming air before combustion.

• But a ramjet decelerates the air tosubsonic velocities before combustion, while airflow in a scramjet is supersonic throughout the entire engine. This allows the scramjet to operate efficiently at extremely high speeds.
• Scramjets are designed to operate in the hypersonic flight regime, beyond the reach of turbojet engines, and, along with ramjets, fill the gap between the high efficiency of turbojets and the high speed of rocket engines.
• Turbo machinery-based engines, while highly efficient at subsonic speeds, become increasingly inefficient at transonic speeds, as the compressor fans found in turbojet engines require subsonic speeds to operate.
• While the flow from transonic to low supersonic speeds can be decelerated to these conditions, doing so at supersonic speeds results in a tremendous increase in temperature and a loss in the total pressure of the flow. Around Mach 3–4, turbo machinery is no longer useful, and ram-style compression becomes the preferred method.
• All scramjet engines have an intake which compresses the incoming air, fuel injectors, a combustion chamber, and a divergent thrust nozzle. Sometimes engines also include a region which acts as aflame holder, although the high stagnation temperatures mean that an area of focused waves may be used, rather than a discrete engine part as seen in turbine engines.
• Other engines use pyrophoric fuel additives, such as silane, to avoid flameout. An isolator between the inlet and combustion chamber is often included to improve the homogeneity of the flow in the combustor and to extend the operating range of the engine.
• A scramjet is reminiscent of a ramjet. In a typical ramjet, the supersonic inflow of the engine is decelerated at the inlet to subsonic speeds and then re accelerated through a nozzle to supersonic speeds to produce thrust. This deceleration, which is produced by a normal shock, creates a total pressureloss which limits the upper operating point of a ramjet engine.

About ISRO:

• The Indian Space Research Organisation is the space agency of the Indian government headquartered in the city of Bangalore. Its vision is to “harness space technology for national development, while pursuing space science research and planetary exploration“.
• Formed in 1969, ISRO superseded the erstwhile Indian National Committee for Space Research (INCOSPAR) established in 1962 by the efforts of independent India’s first Prime Minister, Jawaharlal Nehru, and his close aide and scientist Vikram Sarabhai.
• The establishment of ISRO thus institutionalised space activities in India.It is managed by the Department of Space, which reports to the Prime Minister of India.
• ISRO built India’s firstsatellite, Aryabhata, which was launched by the Soviet Union on 19 April in 1975. In 1980, Rohini became the first satellite to be placed in orbit by an Indian-made launch vehicle, SLV-3. ISRO subsequently developed two other rockets: the Polar Satellite Launch Vehicle (PSLV) for launching satellites into polar orbits and the Geosynchronous Satellite Launch Vehicle (GSLV) for placing satellites into geostationary orbits.
• These rockets have launched numerous communications satellites and earth observation satellites. Satellite navigation systems like GAGAN and IRNSS have been deployed. In January 2014, ISRO successfully used an indigenous cryogenic engine in a GSLV-D5 launch of the GSAT-14.
• ISRO sent one lunar orbiter, Chandrayaan-1, on 22 October 2008 and one Mars orbiter, Mars Orbiter Mission, which successfully entered Mars orbit on 24 September 2014, making India the first nation to succeed on its first attempt, and ISRO the fourth space agency in the world as well as the first space agency in Asia to successfully reach Mars orbit.