Hypersonic missiles offer
some impressive – and disturbing – capabilities.
Between 2014 and June 2015, China conducted four major tests of its hypersonic missiles (with a fifth test in
August). The fourth test of Wu-14, its ultra
high-speed nuclear delivery vehicle, demonstrated a capacity for “extreme
maneuvers.” It was assessed as travelling at a speed of Mach 10 (flying at 10
times the speed of sound or approximately 7,680 miles per hour). To understand
this in comparative terms, a missile flying at subsonic speed can reach a
maximum of 500-600 miles per hour.
To qualify as “hypersonic,” a missile would have to move at least five
times the speed of sound (Mach 5), as well as be able to evade counter-fire and
strike with great precision. To date, no country has achieved this performance
but several nations are working on it.
The fact that China carried out four tests of its hypersonic vehicles in
a span of just 18 months demonstrates the commitment of Beijing to the
development of the technology.
Once operational,
these capabilities would be sufficient to neutralize U.S.
strategic missile defenses; they will be able to avoid triggering early-warning
systems or detection by radar. The critical military value of hypersonic
systems lies in this ability to strike with unprecedented speed and precision.
Four other countries in Asia
are known to be developing civilian or military programs for supersonic and
hypersonic systems: Japan, India, South Korea and Taiwan. Russia is also
pursuing hypersonic capabilities and aims to acquire an operational hypersonic
missile by 2030. India and Russia also
worked together on the hypersonic BrahMos-2.
The
United States is determined not to lose momentum. In June 2015, the Defense
Advanced Research Projects Agency (DARPA) commissioned the arms developer Raytheon to develop
hypersonic missiles. Historically, however, the U.S. has been the trendsetter
in the development of hypersonic systems and China, despite its latest
successes, is now merely playing catch-up. Especially since September 11, 2001,
the U.S. has stepped up its efforts in “prompt global strike”
capabilities. Such capabilities would allow it to deliver explosives
anywhere on Earth within one or two hours.
The consortium of DARPA,
Boeing Integrated Defence Systems, Pratt& Whitney Rocketdyne, and NASA has
been working for more than a decade on developing and testing the X-51, an
unmanned scramjet aircraft designed to meet the requirements of the U.S. Air
Force. The origin of this program dates back to December 2003, when the U.S. Air Force Research
Laboratory launched a scramjet flight demonstrator, to help develop
the X-43 and X-51. From 2005, the program was renamed WaveRider. The first
hypersonic flight test took place in March 2010, with the X-51 reported to have
travelled at Mach-5 but crashing
into the Pacific Ocean when its fuel supply was exhausted. Successive testing
took place in 2011 and 2012 but failed to meet projected goals. The round of
tests and setbacks highlighted the technological difficulties that must be
overcome in order to develop a system that is holistically functional, in terms
of the materials and guidance systems.
Many
critics say the U.S. has been slow to develop the technology, giving a chance
to competing nations to gain ground and causing the U.S. to lose its strategic
advantage that was long assured by its naval supremacy and stealth warplanes.
The
interest in the development of supersonic and hypersonic systems of propulsion
is clearly justified by their outstanding operational capacities, which are far
greater than existing systems. The race for high-speed systems has been
encouraged by the fact that more and more countries have improved their active
counter measures against cruise missiles.
However,
with the technology concurrently developed by several nations, we are on the
brink of a new arms race, with significant risks and new geopolitical
pressures. In this context, some argue that a test ban is necessary.
Why Hypersonic?
For most
operational needs today, subsonic missile speed is generally considered
sufficient. Yet it has proven critically insufficient at key historical
moments. Many strategists remember August 20, 1998. On that day, U.S.
President Bill Clinton tried (and failed) to take out Osama bin Laden by
launching Tomahawk cruise missiles from the Arabian Sea, targeting an Al-Qaeda
training camp in eastern Afghanistan. Travelling at a speed of approximately
550 mph, the Tomahawks needed two hours to reach their target, by which time
bin Laden had already been gone for an hour. This example has often been cited
as an illustrator of the urgency to develop faster systems, able to strike with
greater speeds.
Supersonic and hypersonic
missiles could overcome the constraints of time, distance, and
advanced early warning systems. In a scenario where a missile would have to
travel a distance of 1,000 kilometers to reach its target, a subsonic system
(at 800 km/h) would need 75 min, whereas a supersonic system (Mach 2.8) would
need 17 min and 38 seconds and a hypersonic one (flying at mach 6) just 9 min
and 30 seconds.
The
propulsion system plays a critical role, impacting the speed, range, and
payload of a missile. The major propulsion systems currently in use are
turbojets, turbofans, and ramjets. Supersonic systems are powered by ramjet
engines and operate in the range of Mach 2-4, while hypersonic missiles operate
on scramjet engines and over Mach 5.
To reach
hypersonic speeds, current systems will need to be replaced by what engineers
call “air-breathing” systems, which could be achieved by scramjets (also called
“supersonic-combustion ramjets”). Scramjet technology is only in the
testing phase, and remains one of the greatest technological hurdles in the
development of hypersonic systems.
In
comparison to turbojet and turbofan engines, which have high thrust levels,
ramjet and scramjet engines are simpler in design as they lack rotating
components (and therefore do not have major moving parts such as spinning
blades). However, turbojets consume a lot of fuel, which makes them very heavy
and impractical for long-distance flights.
For
hypersonic speeds of Mach 5 or above, another type of propulsion system would
be required, in which combustion would happen differently. The hypersonic
vehicle would take oxygen from the atmosphere rather than carry it in the form of fuel oxidants.
In the other systems, when a rocket carries its own fuel, it also carries with
it the oxygen needed for combustion in airless space. Scramjets are projected
with a shaped inlet that slows the flow of incoming air but not enough to go
down to subsonic levels. They have a very complex operating cycle and create
numerous difficulties for engineers, in terms of ignition or possible
explosions. Despite these difficulties, the efforts to make hypersonic systems
operational continue.
A Test Ban – Desirable But Unlikely
China’s
claimed success with the first tests of its technology has caused significant
anxiety in the U.S. as well as in other Southeast Asian nations. The U.S.,
which previously recorded several setbacks with hypersonic technology
development, now has further impetus to persevere on its hypersonic projects.
The
emergence of hypersonic systems raises familiar geopolitical tensions. India
and Russia are claiming to have a joint plan to develop a hypersonic missile. Pakistan might be the next to join the race.
Other Western countries will want to invest in the technology as well. There
are few reasons why France or the United Kingdom would not embark on similar
efforts.
Testing
of the technology is crucial in the process of development. To prevent an escalation,
a test ban for hypersonic missiles would provide a strong arms control
mechanism. Some have suggested
that this should begin with an informal moratorium among the countries
currently developing it, including the U.S., China, India and Russia. These
countries would commit to putting their plans to test hypersonic technology on
hold. At the same time, it has been argued that a test ban could be
perceived as discriminatory since some countries have already tested
prototypes of the technology.
The
technology could create enough friction to renew strategic arms races and
geopolitical rivalries. Further trust-building measures and dialogue are
urgently needed, but the prospects are not bright. In general, countries and
international actors have not been very cooperative in the numerous urgent
regulatory steps required by emerging strategic technologies. Globally, we have
still to address existing security threats such as artificial intelligence,
robotic warfare, and synthetic biology. Hypersonic missile development is
likely to proceed at full speed. Tensions between countries, competitiveness,
and national pride will make the option of pursuing hypersonic missiles
attractive, although in the long term, that could be deleterious to a peaceful
international environment.
Prof Nayef Al-Rodhan (@SustainHistory) is an
Honorary Fellow at St. Antony’s College, University of Oxford, and Senior
Fellow and Head of the Geopolitics and Global Futures Programme at the Geneva
Centre for Security Policy. He is the author of Meta-Geopolitics of Outer
Space: An Analysis of Space Power, Security and Governance (Basingstoke: Palgrave
Macmillan, 2012).
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