New Delhi: There is no question of a warning, or even knowing what hit you when a lethal, powerful weapon comes at you ten times faster than the speed of sound — “unstoppable”, “invincible”, and designed to destroy. There’s no need to take any prisoners. Those, at least, are the main selling points of hypersonic missiles, with Vladimir Putin and his trusted generals as their top proponents.
Twice already this month, Russia has claimed that it has fired its state-of-the-art Kinzhal (which means ‘dagger’) hypersonic missile into Ukraine, avowedly making short work of an ammunition storage facility in Diliatyn in the Carpathian Mountains and then a fuel depot in Kostiantynivka near Mykolaiv, on 19 and 20 March, respectively. A few days later, US President Joe Biden also claimed that Russia was resorting to these missiles because they were “impossible to stop“.
Reportedly today #Russia have used hypersonic #Kinzhal missile again. This time on fuel depot in Kostiantynivka, Mykolaiv Oblast. Kinzhal can cover 3.2km in 1 second! It was fired from Crimea, hitting target about 280km away (can reach in about 87 second from Crimea). pic.twitter.com/GH0E51xxTW
— G219_Lost (@in20im) March 20, 2022
While hypersonic technologies have been in development for decades, the Russia-Ukraine war marks the first time they have been used in conflict.
The hype, though, has been intensifying for several years. In 2018, Russian President Vladimir Putin described these missiles as “invincible” and “ideal” weapons, and other countries have also been scrambling to have their own shot at the coolest new wrecking devices in defence technology.
In December 2021, for instance, India’s Defence Minister Rajnath Singh asked the Defence Research and Development Organization (DRDO) to fast-track hypersonic technology development in India. China, too, has claimed that it has developed heat-seeking hypersonic missiles, which sound even scarier.
But, what exactly are hypersonic missiles, and does the bombastic rhetoric around them reflect their true capabilities?
What are hypersonic missiles? How are they different from other missiles?
Hypersonic missiles travel at a speed beyond Mach 5 or 1.6 km per second, approximately five times the speed of sound. Anything above Mach 1 is described as supersonic, and anything above Mach 5 as hypersonic.
However, other missiles can approach similar velocity. What really differentiates hypersonic missiles from the rest is their ability to retain their speed at low altitudes and trajectories within the atmosphere as well as their ability to escape detection.
While intercontinental ballistic missiles can reach speeds of nearly Mach 20, they do so by going outside the atmosphere and not at a low trajectory.
Another significant difference is in manoeuvrability. Once launched, other missiles do not deviate significantly from their flight path.
On the other hand, hypersonic missiles fly within the atmosphere and change and manoeuvre their flight path. This enhances their ability to dodge radars and air defence systems.
In essence, therefore, the importance of hypersonic missiles lies in their ability to overcome the anti-missile and anti-access defence capacities of states through their speed, manoeuvrability, and trajectory.
Given this ability to evade defence systems and enhanced chances of reciprocal strikes, some defence experts believe that hypersonic missiles could potentially end the deterrent capacities of nuclear weapons in the short run.
Col. Stephen Reny of the US Air Force has argued that as one nuclear power attains the capability to defeat ballistic missile defence (BMD) systems, others might feel at a “disadvantage”. This sense of not being able to hit back might cause “strategic instability… arms races, aggressive posturing, and bellicose rhetoric” in the short run, he writes in Strategic Studies Quarterly.
Types of hypersonic technologies
There are two forms of hypersonic technologies — hypersonic cruise missiles and hypersonic glide vehicles.
Hypersonic cruise missiles are faster versions of existing cruise missiles like the Tomahawk. Their superior speed is attributed to them being propelled by rockets or jets.
Hypersonic glide weapons are launched into the upper atmosphere atop ballistic missiles. They then release unpowered hypersonic glide vehicles, moving into the lower atmosphere, while undertaking random trajectories to dodge enemy radars.
The glide vehicles move without propulsion. In contrast, cruise missiles derive their speed through propulsion. The glide vehicles are supposed to move faster than the cruise missiles.
Putting the ‘hype’ in hypersonic?
While the general narrative surrounding hypersonic technologies attributes them with game-changing abilities, there are also questions regarding their actual ability.
To start with, are hypersonic glide vehicles as fast as they are touted to be? Physicists are sceptical because of the “drag” phenomenon.
Drag, in this context, refers to a form of fluid resistance or friction, i.e., the resistance a fluid gives to an object that is moving because of it.
When fluid flows through an object or an object moves through a stationary fluid, the fluid exerts a force on the object in the opposite direction of the object’s movement.
This resistance acts as a considerable hindrance to the speed and flow of any object. This resistance is the “drag” phenomenon.
For a flying object, drag depends on air density, among other factors, and increases in relation to the square of its velocity. Thus, making drag rather severe at hypersonic speeds. At speeds of Mach 5, drag is nearly 25 times that at Mach 1.
Given the attributed Mach 5 speeds of hypersonic glide vehicles, physicists argue that “drag” will be a major hindrance in them being able to maintain their hypersonic speeds.
Secondly, physicist Dr David Wright and material scientist Cameron L. Tracy, in a 2021 paper published in Science & Global Security, state that hypersonic vehicles will not be able to outwit detection systems and satellites. Their argument is that space-based sensors can track the trajectory of these hypersonic technologies.
Thirdly, Wright and Tracy argue that due to their extreme speeds, the surfaces of hypersonics heat up to temperatures of thousands of degrees. The heating hampers the aerodynamics of gliders as their wings and noses may lose shape, thereby reducing their efficiency. The heating also enables detectors and sensors to detect these glide vehicles.
These questions are enough to at least raise an eyebrow about the claimed speeds, undetectability, and manoeuvrability of hypersonic technologies.
India’s hypersonic programme
In September 2020, India successfully test-fired a hypersonic missile carrier, becoming the fourth country to achieve this feat after the US, Russia, and China. Rajnath Singh had also tweeted around this time that “all critical technologies” had been established to get to the “next phase”.
The @DRDO_India has today successfully flight tested the Hypersonic Technology Demontrator Vehicle using the indigenously developed scramjet propulsion system. With this success, all critical technologies are now established to progress to the next phase.
— Rajnath Singh (@rajnathsingh) September 7, 2020
According to an October 2021 report of the Congressional Research Service (CRS), which is a public policy research institute of the US Congress, India operates approximately 12 hypersonic wind tunnels and can test speeds of up to Mach 13.
The report also says that India collaborated with Russia to develop BrahMos II and is developing an “indigenous, dual-capable hypersonic cruise missile”. Indeed, earlier this week, several news reports quoted US senator Jack Reed as saying that India was among the countries that had “advantages” over the US as far as hypersonic technology goes.
(Edited by Asavari Singh)