Page 49 - Australian Defence Magazine October 2019

THE warship is dead and hypersonic mis- siles are overrated.
The two halves of that sentence seem to oppose each other. After all, there’s been a lot of talk in recent months of the need to redesign Australia’s force posture to meet the rising threat from China, and much of this talk is based on the assumption that Beijing’s hypersonic missile technology is about to end the reign of warships.
Most notably, renowned strategist Hugh White has called for the government and the ADF to plan to defend Australia alone. White’s argument is based on a premise he previously argued in a 2017 Quarterly Essay, Without America: Washington will lose stra- tegic leadership in Asia in the face of China’s growth trajectory and rising ambition.
To independently defend the conti- nent’s sea and air approaches, White calls for Australia to raise defence spending to 3.5 per cent of GDP, increase our subma- rine fleet fourfold, double the number of fighter aircraft, sell the newly-built Ho- bart-class air warfare destroyers and the Canberra-class landing helicopter docks, cancel the contract for the Hunter-class frigates and contemplate acquiring nucle- ar missiles.
White’s plan aims to reduce the ADF’s dependence on large surface ships that he believes are indefensible against hyper- sonic missiles. White’s plan, in a nutshell, assumesthathypersonicmissileswillkill the warship.
This plan has copped some criticism. Michael Shoebridge of ASPI observed that White’s argument misses the role of surface ships in protecting shipping and thus sustaining the war effort.
“Strategy is about more than fighting, it’s about shaping the environment so that war is prevented and if it has to be fought, it’s fought from the strongest position,” Shoe- bridge argued. “None of White’s proposed force structure seems well-placed to pro- tect shipping and aircraft bringing what our economy would need to sustain a con- flict lasting more than a couple of weeks.”
Others have put forward alternative plans, however, that also suggest hyper- sonic missiles are about to end the era of large surface vessels. Professor Andrew Davies of ANU has argued that “large and slow multi-billion-dollar platforms constrained to a two-dimensional surface have little future in the 21st century.”
ASPI’s Dr Malcom Davis cites the Hud- son Institute: “It is the hypersonic mis- sile capability that will keep us out of the Indo-Pacific and [will render] aircraft car- riers operationally useless.” If this is true, it is safe to expect a similar effect on the usefulness of large frigates and destroyers.
But is this assumption correct? Will hypersonic missiles really end the era of warships?
The answer is no - but not only because hypersonic missiles are overrated. Hyper- sonics won’t kill the warship because the warship is already dead.
What are hypersonic missiles?
Hypersonic missiles are, as the name im- plies, missiles that are capable of reaching hypersonic velocities of at least five times the speed of sound (Mach 5).
Hypersonics fall into two broad cat- egories; scramjets and boost glide missiles. Boost glide variants are
taken to high altitudes by a rocket
before they are released to glide towards the target. Their advan- tage lies in the fact that the rocket technology required is well-un- derstood and less expensive than scramjets.
Scramjet missiles, on the other
hand, use a booster to reach hy- personic speeds, at which point
an ‘air-breathing’ engine takes
over to compress incoming air before combustion with no moving parts. This propulsion mechanism could allow sc- ramjet missiles to achieve greater ranges than boost glide variants, but developing these engines is technical and costly.
“The difference between a boost glide and a scramjet is the same as the difference between normal surface-to-air missiles and cruise missiles,” Brad Yelland, Chief Technology Officer for BAE Systems Australia, explained to ADM. “Boost glides have a large, usually solid propellant rocket motor that boosts the flight vehicle up to hypersonic speeds. The vehicle then ejects the boost motor and glides on. From the moment you eject the boost motor, you’re slowing down.
“With a scramjet, the engine sustains that speed. You’re still using a boost motor to get up to speed, but your range is now only dependent on the fuel you’ve got to burn. But scramjets are expensive, highly
technical and very difficult, whereas boost glides are pretty simple.”
The physics behind hypersonic flight have been known for decades. Yet devel- opments in material composites have only recently allowed aircraft to withstand the temperatures of hypersonic flight for use- ful periods of time. New power generation technologies are also enabling hypersonic missiles to stay in the air for longer.
“When you look at the physics of it, there’s no revolution,” Yelland said. “But the ability to fly for long periods of time at high speeds causes all kinds of heat and power generation problems.
“These things are glowing hot; cryogen- ic-type cooling is difficult if you haven’t got the ability to manufacture novel shapes with in-built cavities. 3D printing now allows us to develop cooling systems internal to the structure itself.
“Steering something going at Mach 10 also takes a lot of energy, and the technology around the generation, stor- age and management of electrical en- ergy has changed.”
The next arms race
The US has pioneered much of the new research into hypersonic flight. NASA’s X-43 scramjet vehicle successfully reached Mach 9.6 in 2004 and its successor, Boe- ing’s X-51, flew at Mach 5.1 for roughly 210 seconds in 2013. The Pentagon’s Un- dersecretary for Research and Engineer- ing, Michael Griffin, has reportedly priori- tised hypersonics development above every other program.
Other countries are also putting in sig- nificant effort. Russian President Vladi- mir Putin has claimed that his country has two operational hypersonic missile types with a third submarine-launched variant in development. France and India are
www.australiandefence.com.au | October 2019 | 49
“Hypersonic missiles are overrated. Hypersonics won’t kill the warship because the warship
is already dead.”