The past month has been quite eventful in the world of advanced military tech, sparking new concerns for the US and its Western allies. Russia, China and North Korea, all countries that share strained ties with the US, have claimed they are able to develop hypersonic missiles that have the power to go completely undetected on US radars.
This technology has the potential to be one of the world's fastest and most accurate weapons -- and could be fitted with a nuclear warhead, experts say.
It has the power to reestablish the limitations of Inter Continental Ballistic Missiles (ICBMs) by rendering existing missile defence systems futile and making it next to impossible for target nations to predict its trajectory or target, even if the missile is somehow detected in advance.
This leap in technology is raising tough questions for the US and its allies because the principles for when to use hypersonics have not been set and the ramifications of using them have not been thought through. Until a strategy for dealing with them catches up, the concept of mutual deterrence is the only shield between US strategic locations and these rival countries' updated arsenal.
Is the hypersonic threat here now?
Russia, China, the United States and North Korea have all test-launched hypersonic missiles. France, Germany, Australia, India and Japan are working on hypersonics, and Iran, Israel and South Korea have conducted basic research on the technology, according to a recent report by the US Congressional Research Service (CRS).
Among US enemies, Russia farthest along in commissioning hypersonic missile arsenals
The Financial Times report, citing multiple sources familiar with the test, said Beijing's nuclear-capable missile circled the Earth at low orbit before descending toward its target, which three sources said it missed by over 20 miles (32 kilometres). China, however, has denied these reports and claimed it has only tested a hypersonic vehicle (and not missile) which it intends to use for a peaceful space programme.
And although not much is known about the specifications of the North Korean projectile, experts have raised doubts about the country's capabilities to successfully produce and deploy a hypersonic weapon. "North Korea's test announcement suggested they had much further to go, that the test focused on manoeuvrability and flight characteristics. Based on an assessment of its characteristics such as speed, it is at an initial phase of development and will take a considerable time to be deployed," the South Korean and US militaries said in a statement.
But the Russian Zircon missile is a different story altogether!
The Russian Defense Ministry said that the Severodvinsk submarine performed two launches of the Zircon cruise missile at mock targets in the Barents Sea. It first test-fired Zircon from the surface and then launched another missile from a submerged position in the White Sea. The launch marked Zircon's first launch from a submarine. It previously has been repeatedly test-fired from a navy frigate, most recently in July. Officials said Zircon's tests are to be completed later this year and it will be commissioned by the Russian navy in 2022.
Russian President Vladimir Putin has said Zircon would be capable of flying at nine times the speed of sound and have a range of 1,000 kilometres (620 miles). Putin has emphasized that its deployment will significantly boost Russian military capability.
Why do countries want hypersonics?
Experts say hypersonics do not necessarily upend the global nuclear balance, but instead add a potent new delivery method to the traditional triad of bombers, ground-launched ICBMs, and submarine-launched ballistic missiles.
Hypersonic missiles, like traditional ballistic missiles which can deliver nuclear weapons, can fly more than five times the speed of sound. But ballistic missiles fly high into space in an arc to reach their target, while a hypersonic flies on a trajectory low in the atmosphere, potentially reaching a target more quickly. Traditional ballistic missiles and ICBMs too can travel very fast, beating the speed of sound, but because they arc along a predictable ballistic path, like a bullet, they lack the element of surprise.
In contrast, a hypersonic missile packs the manoeuvrability of much slower subsonic cruise missiles and the hypersonic speed greater than or equal to ICBMs, making it harder to track and defend against.
While countries like the United States have developed systems designed to defend against cruise and ballistic missiles, the ability to track and take down a hypersonic missile remains a question.
Hypersonic missiles can be used to deliver conventional warheads, more rapidly and precisely than other missiles. But their capacity to deliver nuclear weapons could add to a country's threat, increasing the danger of a nuclear conflict.
And, underscoring the attractiveness of hypersonics, the CRS report says that the US missile defence system is inadequate to detect, track and respond in time to hypersonics.
For instance, a US Aegis missile interceptor systems require 8-10 seconds of reaction time to intercept incoming attacks. In those 8-10 seconds, the Russian Zircon missiles will already have travelled 20 kilometres, and the interceptor missiles do not fly fast enough to catch up, according to a US-based defence news portal Military.com
What's the US doing?
The US Defense Department has an aggressive development program, planning up to 40 tests over the next five years, pouring more than $1 billion annually into hypersonic research, according to a government report.
The Pentagon tested a scramjet-powered hypersonic last week, calling it "a successful demonstration of the capabilities that will make hypersonic cruise missiles a highly effective tool for our warfighters."
But if reports are to be believed, the US might have missed the bus on this one. US scientists have been indulging in the early stages of experiments since the dawn of the Cold War. But the Pentagon has periodically thrown its weight behind the development of manoeuvrable hypersonic weapons, only to shy away when technological hurdles such as propulsion, control, and heat resistance proved daunting.
"You see a flurry of activity, a lot of investment, and then we conclude it's a bridge too far," says aerospace engineer Mark Lewis, director of defence research and engineering for modernization at the US Department of Defense (DOD). "The community was underfunded and largely forgotten for many years," adds Daniel DeLaurentis, director of Purdue University's Institute for Global Security and Defense Innovation told Science magazine.
But most US hypersonic weapons, in contrast to those in Russia and China, are not being designed for use with a nuclear warhead. As a result, US hypersonic weapons will likely require greater accuracy and will be more technically challenging to develop than nuclear-armed Chinese and Russian systems, according to the Congressional research report said.
Is the threat real?
Theoretically, hypersonic cruise missiles and boost-glide vehicles travel six to 10 times faster than the speed of sound and can manoeuvre far more effectively at high speeds than their non-hypersonic counterparts.
These weapons enable countries to strike targets before enemies can react and to defeat missile-defence systems through speed and manoeuvrability. The largest threat they pose is because of the unpredictability of their targets and the intensity they pack.
But the real threat is that this new arms race promises to upend strategic calculations of nuclear non-nuclear war deterrence.
A US Congressional report, Hypersonic Weapons: Background and Issues for Congress, published in August, points out the use of this technology could lead to an unintended escalation of a conflict. The missiles' short flight times leave little time for countries to decide how to respond, so it may incur knee-jerk counterattacks from the target nation. Another factor is that their unpredictable flight paths, a much-talked-about key advantage, may turn to the attacker's disadvantage because uncertainly about their intended targets can lead countries that aren't being targeted to respond by mistake. Also, ambiguity about whether an incoming weapon is equipped with a conventional or nuclear warhead could trigger a nuclear response in error.
Cameron Tracy, an arms control expert at Stanford University, says the solution is to include hypersonics in nuclear arms control negotiations -- though currently North Korea and China are not part of any pacts.
"The development of these weapons, this hypersonic arms race, is probably not the most stable situation. So it would be good to act as quickly as possible," said Tracy.
With inputs from agencies