Defence Minister Rajnath Singh during the inauguration of indigenously developed advanced Hypersonic Wind Tunnel (HWT) test facility

HWT is essential to meet R&D needs for designing futuristic hypersonic missiles

With Chandrayaan-3’s calibrated touchdown on the lunar surface on Wednesday, India has become the fourth country— after the US, China, and Russia—to have the capability to conduct soft landings on the moon. India is also the fourth country—after the big three again—to have the home-grown capability to develop and set up Hypersonic Wind Tunnel (HWT).

However, the irony is that the HWT, built at a cost of Rs 400 crore after the initiation of the proposal by the Defence Research and Development Laboratory (DRDL), is finding very few users to test hypersonic technology in India.

A laboratory under the DRDO, DRDL is responsible for the design and development of state-of-the-art missile systems and technologies.

According to a CAG audit report tabled recently in Parliament, while the HWT was commissioned in October 2019, in the succeeding three years till November 2022, only a total of 500 tests have been conducted “which is a mere 33 per cent of the number of tests estimated to be conducted in the project proposal. This indicates that the number of tests was estimated on the higher side”.

The audit report added: “The number of test-runs over a period of five years was estimated to be about 2,500 (approximately 500 per annum), which included 1,000 tests for current projects, 1,000 tests for planned projects and 500 tests for research and development.”

The HWT—a pressure vacuum-driven enclosed free jet facility having nozzle exit diameter of 1 metre and will simulate Mach No 5 to 12 (Mach represents the multiplication factor to the speed of sound)—located in Hyderabad, is essential to meet research and development requirements for designing of futuristic hypersonic missiles and re-entry vehicles that require generation of extensive aerodynamic data. It has the potential of substantially reducing the cost of launching satellites which is a booming business sector for India’s space effort. India has launched 431 satellites for 36 countries till July 2023.

Hypersonic technology—which enables projectiles to travel at a speed of more than Mach 5—is among the buzzwords of contemporary cutting-edge military technology with many nations across the world setting aside funds for research and development of such technology.

The challenges to hypersonics include extreme heat and pressure besides control over flight trajectories.

The HWT simulates hypersonic conditions by directing hypersonic airflows inside a large tube wherein objects reach the flying stage.

DRDL’s HWT project also suffered from delays due to lack of prioritisation of critical activities as the Wind Tunnel System which should have got due priority for installation did not receive the same. “The Wind Tunnel systems (WTS), was a major system of the facility and all other subsystems were to be interfaced with the same. Hence, initiating action for creating the WTS facility first was of paramount importance,” the national auditor reported.