Scramjet: A look at the vehicle and its development, and the importance of the test for defence and other sectors.

The scramjets are a variant of a category of jet engines called the air breathing engines. The ability of engines to handle airflows of speeds in multiples of speed of sound, gives it a capability of operating at those speeds.

The Defence Research and Development Organisation (DRDO) on Monday successfully flight tested the Hypersonic Technology Demonstrator Vehicle (HSTDV) – an unmanned scramjet vehicle with a capability to travel at six times the speed of sound.

A look at the vehicle and its development, and the importance of the test for defence and other sectors.

Significance of The Test

The DRDO said in a series of tweets, “In a historic mission today, India successfully flight tested Hypersonic Technology Demonstrator Vehicle, a giant leap in indigenous defence technologies and significant milestone towards a Sashakt Bharat and Atmanirbhar Bharat. DRDO with this mission, has demonstrated capabilities for highly complex technology that will serve as the building block for NextGen Hypersonic vehicles in partnership with industry.”

The test which was conducted from Dr APJ Abdul Kalam Launch Complex at Wheeler Island, off the coast of Odisha today, the Agni missile was used. A solid rocket motor of Agni missile was used to take to an altitude of 30 kilometres where the cruise vehicle separated from the launch vehicle and the air intake opened as planned. The parameters of the test were monitored by multiple tracking radars, electro-optical systems and telemetry stations and a ship was also deployed in the Bay of Bengal to monitor the performance during the cruise phase of hypersonic vehicle. All the performance parameters have indicated a resounding success of the mission, officials said.

A senior DRDO scientist said that though the system was tested for a very short duration, it has given scientists a large set of data points to work on for further development. The indigenous development of the technology will also boost the development of the systems built with hypersonic vehicles at its core, including both offensive and defensive hypersonic cruise missile systems and also in the space sector.

Scientists believe that while the successful test is a major milestone, many more rounds of tests will have to be done to achieve the level of technology with countries like the US, Russia and China. “This is certainly a milestone, but developers will have to look at it as a stepping stone.” A DRDO scientist, who was part of the project said.

The Hypersonic Vehicle And Its Scramjet Engine

The scramjets are a variant of a category of jet engines called the air breathing engines. The ability of engines to handle airflows of speeds in multiples of speed of sound, gives it a capability of operating at those speeds.

Hypersonic speeds are those which are five times or more than the speed of sound. The unit tested by the DRDO can achieve up to six times the speed of sound or Mach 6, which is well over 7000 kilometres per hour or around two kilometres per second.

For the test on Monday, the hypersonic combustion sustained and the cruise vehicle continued on its desired flight path at a velocity of Mach 6 for a period of 20 seconds. “The critical events like fuel injection and auto ignition of scramjet demonstrated technological maturity. The scramjet engine performed in a text book manner.” The DRDO said. While the technology helps achieve hypersonic speeds, it comes with its set of disadvantages, and the obvious one being its very high cost and high thrust-to-weight ratio.

Development of The Technology

The DRDO started on the development of the engine in early 2010s. The Indian Space Research Organisation (ISRO) has also worked on the development of the technology and has successfully tested a system in 2016. DRDO too has conducted a test of this system in June 2019.

The special project of the DRDO consisted of contributions from its multiple facilities including the Pune headquartered Armament and Combat Engineering Cluster. “At the hypersonic speeds, the system has to handle temperatures to the range of 2500 degrees celsius as well as the air speed, and thus development of the material is one of the main challenges.” said a DRDO scientist.

For this project, DRDO used many technologies already available with it. After the test on Monday, Defence Minister Rajnath Singh tweeted, “The DRDO has today successfully flight tested the Hypersonic Technology Demonstrator Vehicle using the indigenously developed scramjet propulsion system. With this success, all critical technologies are now established to progress to the next phase.”