The indigenous HSTDV, which in the future could serve as a critical building block for hypersonic weapons with speeds over Mach 5, was tested from the APJ Abdul Kalam Island off the Odisha coast in the afternoon, sources said.
There was, however, no official word from either the defence ministry or DRDO on whether the test was successful or not. A source, in turn, said, “The initial launch and take-off was successful. But there are question marks on the subsequent performance of the scramjet engine of the HSTDV for which the data has to be analysed in detail.”
The first test of the HSTDV failed in June 2019. But the second one in September 2020 was successful to the extent that the scramjet-powered `cruise vehicle’ or HSTDV flew for 22-23 seconds at Mach 6 speed after separation from the `launch vehicle’ of solid rocket motor of an Agni-I ballistic missile at a 30-km altitude.
Flight tests of a much longer duration — at least a few minutes — will be required to eventually develop hypersonic weapons, which could become a reality after five to six years.
India’s intent to develop hypersonic weapons was made quite clear by defence minister Rajnath Singh when he directed the DRDO in December 2021 to move swiftly towards developing such an arsenal to `maintain’ the country’s minimum credible deterrence against adversaries, as was then reported by TOI.
The directive had come after China had tested a nuclear-capable missile carrying a hypersonic glide vehicle and warhead in July that year. China has forged ahead of even the US in developing hypersonic weapons with nuclear warheads. Both China and Russia, in fact, are regarded to be ahead of the US in designing aerodynamically manoeuverable hypersonic weapons for use with nuclear warheads.
Hypersonic weapons are basically of two types. One, hypersonic cruise missiles that are powered by high-speed, air-breathing engines or “scramjets” during their entire flight. And two, hypersonic glide vehicles that are launched atop ballistic missiles before gliding to their targets at speeds over Mach 5.
Hypersonic weapons pose a challenge to the current missile and air defence systems due to their enormous speed and manoeuvrability, both vertically and horizontally, as well as low altitudes of flight.
The Indian armed forces already have the conventional ramjet-powered BrahMos supersonic cruise missiles, which fly at Mach 2.8 speed, developed jointly with Russia. Their strike range has been enhanced from the original 290-km to 450-km now. But while ramjet engines operate well at supersonic speeds around Mach 3, their efficiency drops at hypersonic speeds.
