We don't know how to defend against hypersonic missiles.
Hypersonic weapons can be destabilizing.
It creates an escalatory environment.
It increases the likelihood of a strategic conflict, and it decreases the ability to defend against it.
Flight speed is often compared to the speed of sound.
The speed of sound, that's Mach 1.
Sound travels through air about 10 times as fast as we drive on the freeway.
Commercial airliners, for example, fly subsonically, right under Mach 1.
A modern fighter can travel supersonically at Mach 2 or 3.
Anything Mach 5 and above, we're calling hypersonic speeds.
Mach 25 is about the upper limit.
We do have space shuttles that go hypersonically, that go Mach 20 or 24.
However, it is only flying hypersonically for a relatively short period of time.
But technology is just now emerging which will enable sustained hypersonic flight.
There are three primary hurdles to the development of hypersonic weapons.
First, the aerodynamics and flight control at hypersonic speeds are a major challenge.
The second has to do with material science.
You can think of it as flying into this blowtorch.
The faster a vehicle flies, the pressure and temperature rises exponentially.
So you have to have materials that can withstand the high temperatures over a long period of time.
The third challenge involves the propulsion system of hypersonic cruise missiles.
Once you reach Mach 5, you can't use your traditional jets and just make them go faster.
You need a completely different design to unclutter the flow path and sustain combustion
of the supersonic airflow inside the engine.
It has been compared to lighting a match in a 2,000-mile-an-hour wind.
And then the integration of all of these technologies into a weapons system is in itself, a challenge.
The three countries that are getting close to being able to deploy them are Russia, China,
and the U.S.
It's probably less than a decade for these top three countries.
Other countries, however, are much further behind.
In part, because the technical challenges and the engineering challenges for these weapons
require massive amounts of investment.
So they would require extensive foreign assistance.
However, as time goes on, the knowledge related to these technologies are going to start proliferating.
There really are two types of missiles emerging: hypersonic cruise missiles and hypersonic glide vehicles.
Hypersonic cruise missiles are powered all the way to their targets using an advanced
propulsion system call a scramjet.
These are very, very fast.
You may have six minutes from the time it's launched until the time it strikes.
So hypersonic glide vehicles are just that.
They're a very fast glider.
The way it's launched is they put it on top of a rocket that re-enters, then it flies on
top of the atmosphere, like a plane with no engine on it.
It uses aerodynamic forces to maintain stability, to fly along and to maneuver.
Because it's maneuverable, it can keep its target a secret up until the last few seconds of its flight.
The current types of missile defenses are not adequate to defend against hypersonic missiles.
Our whole defensive system is based on the assumption that you're going to intercept
a ballistic object.
A ballistic missile is like a fly ball in baseball.
The outfielder knows exactly where to catch it, because its path is determined by momentum and gravity.
It's a different scenario.
The combination of the maneuverability and the speed makes hypersonic missiles unpredictable
and extremely difficult to defend against.
The faster you go, the more kinetic energy you have.
In some cases, you may not need to put any explosives on it.
The kinetic energy of the vehicle itself is sufficient to be able to cause quite a bit of destruction.
Most countries use some form of what we call an OODA loop when they're making decisions
about whether to respond to a threat or not.
You observe a threat.
You figure out where it's coming from,
then decide whether you need to respond, and then act on that decision.
How are you going to shoehorn all those steps into six minutes?
There are two implications here.
The first is that people will become more trigger-happy.
The compressed time frame to make a decision makes people much more likely to want to be
the first strike as opposed to the second strike, because you can't preserve your second-strike capabilities.
The second implication is that if you can't defend against a decapitation attack, then
you have to devolve command and control of your weapons into the field.
To the military, rather than to the national leaders.
That runs the risk of an accidental strategic war.
Another possibility is to disperse your strategic weapons.
That runs the risk of the weapons being seized by terrorists.
Another possibility is to go to a strategic doctrine called "launch on warning."
And finally, you could just decide in a crisis that there is going to be a full-scale strategic
conflict, and you strike first.
None of these options is very good.
I think the world will be a more dangerous, place unless we have some sort of an agreement
with each other to not share those technologies.
The end state that we're trying to avoid is the proliferation of hypersonic technology,
not just to rogue nations, but also to nations with regional rivalries that could prove to
be very destabilizing.
What we're recommending is a kind of addendum or amendments to the Missile Technology Control Regime.
This regime could be supplemented with some controls on hypersonic components.
It would be waste of time to do this if the U.S. or Russia or China plan to export complete missiles.
If you can just start with a trilateral agreement between these three major nations, that would
be taking a really effective step in terms of controlling proliferation of these weapons.
I am optimistic about the U.S., Russia, and China.
It's in their interest to do this.
And there's time to do it.
Not a lot of time, but a few years.