The maiden launch of an indigenously-developed hypersonic technology demonstrator vehicle (HSTDV), powered by a scramjet engine, from the Dr Abdul Kalam Island off the Odisha coast failed to achieve the technical parameters laid down for the test on Wednesday.
Defence sources said the HSTDV, designed to cruise at Mach 6 speed with the scramjet engine, was supposed to “fire and fly on its own” after being carried to an altitude of around 30-40 km by the solid rocket motor of an Agni-I ballistic missile in the test.

“But the Agni-I booster went into an uncontrolled mode after the launch and could not achieve the desired altitude…So, the entire test flopped,” said a source.The cruise vehicle (HSTDV) was supposed to be ejected out of the launch vehicle (Agni-I) and be propelled by the scramjet engine after it auto-ignited at the required altitude but it failed to do so during the test. The test was considered critical for the development of a hypersonic (over Mach 5 speeds) cruise missile system in the future.

The DRDO, however, said the “internal experimental test” of the technology demonstrator vehicle was meant to prove “a number of critical technologies” for futuristic missions. “The missile was successfully launched at 11.27 am. Various radars, telemetry stations and electro-optical tracking sensors tracked the vehicle through its course. The data has been collected and will be analyzed to validate the critical technologies,” it added. But DRDO refused to say anything about the overall outcome of the test.

The HSTDV project is basically aimed at demonstrating autonomous flight of a scramjet integrated vehicle using kerosene, which can have multiple civilian applications, including launching satellites at a low-cost, as well as military uses in the shape of long-range cruise missiles.
A scramjet engine is an improvement over the ramjet engine because the former operates efficiently at hypersonic speeds and allows supersonic combustion. Ramjets, in contrast, operate well at supersonic speeds around Mach 3 but their efficiency drops at hypersonic speeds.