Mystery still surrounds China’s hypersonic missile test nearly a week after news broke that shocked the world of defense.
In the hallowed halls of the Pentagon, United States experts are still scratching their heads trying to work it all out.
Could China have successfully launched a “submunition” from a hypersonic glide vehicle (HGV) while it was screaming through the atmosphere at Mach 5-plus?
For the uninitiated, the definition of a “submunition” is a “small weapon or device that is part of a larger warhead and separates from it before impact.”
Science and weapons specialists have said the China test is against the laws of physics. It simply cannot be done – at least with our technology.
The answer, it appears, is perhaps.
“From a general standpoint, deploying something at hypersonic speeds, is really, really, really, really hard,” Mark Lewis, the executive director of the National Defense Industrial Association’s Emerging Technologies Institute and an expert on hypersonics, told the Breaking Defense website.
“And if anyone were to do that, that would be super impressive,” he added.
According to a report in the Financial Times last week, it was a secret test of a powerful new kind of hypersonic missile. There is a historical analogy, of sorts.
Two decades ago, the Defense Advanced Research Projects Agency (DARPA) – the arm of the US Department of Defense that funds advanced R&D – worked on a project known as the Common Aero Vehicle (CAV), which included a suborbital HGV that could deliver conventional weapons anywhere in the world within two hours.
But DARPA could never get the system to work right due to a number of design problems that ran into the laws of physics, Lewis said. The effort was eventually killed in 2004 by the US Congress, out of political concerns that it was strategically destabilizing.
One key issue for deploying “submunitions” from HGVs is that when two vehicles are moving above Mach 1, they create shock waves that can interfere and cause the “small weapon or device” to bounce back into its parent vehicle, destroying both.
This actually happened, according to the Global Security website, in a 1966 test of an air-breathing drone, called the D-21 Tagboard, launched from a supersonic jet – the precursor of the SR-71. The test resulted in a crash that killed one of the jet pilots and caused legendary Lockheed Martin engineer Kelly Johnson to terminate the program.
To avoid that problem, the Common Aero Vehicle was designed to dramatically slow down. And, it is possible that this is exactly what the Chinese HGV did too, Breaking Defense reported.
“A vehicle like a CAV would lose speed as it glided at low altitudes since it is not powered. You could imagine having the [Chinese] payload be a smaller vehicle that did carry propellant so that it would gain speed fast enough to out-maneuver defenses,” David Wright, a theoretical condensed matter physicist affiliated with MIT’s Laboratory for Nuclear Security and Policy, said in an email.
“It might be released when the CAV had slowed to non-hypersonic speeds,” he added.
It is also possible to overcome the shock wave problem, according to one industry expert. In fact, the US actually has data on this so-called “wake effect” from its years of experience with the Space Shuttle.
“A hypersonic object interacting with the rarified atmosphere creates an area of low pressure directly adjacent to the hull of the object. [The] clever design of surfaces could create an area of low pressure large enough for a submunition to be deployed away from the primary vehicle,” the industry expert said
Meanwhile, some specialists remain skeptical. Did this actually happen? Again, nobody really knows, for sure.
Part of the problem is that the DOD continues to be vague about what the US government knows, except to frantically ring the alarm bells about China moving ahead of the US on hypersonic weapons research, Breaking Defense reported.
Victoria Samson, the head of Secure World Foundation’s Washington Office, noted that there are a lot of questions about public reports regarding the Chinese test, adding that “calling it ‘breaking the laws of physics’ does not lead to rational scrutiny.”
While US officials keep saying that the HGV is nuclear-capable, the Pentagon has released no information on how officials have determined that. Samson — whose organization publishes an annual study on Global Counterspace Capabilities — further stressed that up to now, China is known only to have been testing a conventional HGV, the DF-ZF.
Wright added that there is a reason to be concerned that those worried about the lack of investment by the DOD in hypersonics are hyping both Russian and Chinese progress as a way to generate more fear. That would result in more funding, Breaking Defense reported.
“I have been told by others following the debate on these issues that those in the US who want to pursue hypersonic weapons have been really playing up the Russian and Chinese ‘lead’ in the field as a motivating factor,” he said.
“The Pentagon may have been surprised that China would conduct a test like this – although [Beijing] has been open about trying to counter US defenses – but it could not have been surprised about the technology used,” Wright added.
Hypersonic cruise missile
Meanwhile, China isn’t the only country developing hypersonic missile technology. According to Interesting Engineering, Russia claimed earlier this month that it had successfully fired a hypersonic missile from a submarine.
Just a few weeks before the test, the US successfully fired a hypersonic cruise missile. North Korea has also claimed to have carried out its first hypersonic missile test in September.
Traveling at five times the speed of sound, hypersonic missiles are similar to the ballistic variety and can deliver nuclear weapons.
But unlike ballistic missiles that fly high up to space and back down again in an arc, hypersonics fly at lower trajectories and are more maneuverable, making them a difficult target to track and defend against.
Sources: Breaking Defense, Financial Times, Global Securities, US Department of Defense, Interesting Engineering.