MUMBAI: The Indian satellite launch program got a shot in the arm this morning at 6 am with the Indian Space Research Organisation (ISRO) successfully test firing its Supersonic Combustion Ramjet (scramjet) or air breathing engine from the spaceport of Sriharikota.
Usually rocket engines carry both fuel and an oxidiser tank on board for combustion, scramjets use oxygen from the atmosphere The newly developed engines make the spacecraft’s weight ligher, smaller and faster – thereby reducing launch costs.
Two scramjets were used on a RH-560 big sounding rocket that took off from the Satish Dhawan Space Centre. 11 km into space and 55 seconds into flight, the two scramjets were tested for six seconds. And the tests proved successful.
Scientists from the Vikram Sarabhai Space Centre (VSSC) and Liquid Propulsion Systems Centre (LPSC) who were at Sriharikota had earlier told The Times of India that the Air-Breathing Propulsion System (ABPS) technology scramjets would be used to power the advanced reusable launch vehicle, which can return to earth after depositing the payload into its designation orbit.
The scramjet test was planned for July 21 this year but was postponed as ISRO was assisting in the search operations to locate the missing IAF aircraft AN-32.
After a smooth countdown of 12 hours, the solid rocket booster carrying the scramjet engines, lifted off at 0600 hrs (6:00 am) IST. The important flight events, namely, burn out of booster rocket stage, ignition of second stage solid rocket, functioning of Scramjet engines for 5 seconds followed by burn out of the second stage took place exactly as planned.
After a flight of about 300 seconds, the vehicle touched down in the Bay of Bengal, approximately 320 km from Sriharikota. The vehicle was successfully tracked during its flight from the ground stations at Sriharikota.
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.
The scramjet engine designed by ISRO uses Hydrogen as fuel and the Oxygen from the atmospheric air as the oxidiser. Today’s test was the maiden short duration experimental test of ISRO’s scramjet engine with a hypersonic flight at Mach 6. ISRO’s Advanced Technology Vehicle (ATV), which is an advanced sounding rocket, was the solid rocket booster used for today’s test of scramjet engines at supersonic conditions. ATV carrying scramjet engines weighed 3277 kg at lift-off.
ATV is a two stage spin stabilised launcher with identical solid motors (based on Rohini RH560 sounding rocket) as the first as well as the second stage (booster and sustainer). The twin scramjet engines were mounted on the back of the second stage. Once the second stage reached the desired conditions for engine “Start-up”, necessary actions were initiated to ignite the Scramjet engines and they functioned for about 5 seconds. Today’s ATV flight operations were based on a pre-programmed sequence.
Some of the technological challenges handled by ISRO during the development of Scramjet engine include the design and development of Hypersonic engine air intake, the supersonic combustor, development of materials withstanding very high temperatures, computational tools to simulate hypersonic flow, ensuring performance and operability of the engine across a wide range of flight speeds, proper thermal management and ground testing of the engines.
India is the fourth country to demonstrate the flight testing of scramjet engine. The successful technology demonstration of air-breathing scramjet engines in flight by ISRO today is a modest yet important milestone in its endeavour to design and develop advanced air breathing engines including engines for ISRO’s future space transportation system.
