The hypersonic threat that keeps US commanders up at night

It travels at more than five times the speed of sound, more than a mile per second, below U.S. missile defenses. It can carry conventional or nuclear weapons, able to reach anywhere in the world in three hours or less, and both China and Russia are developing them, as is the U.S.

The scary weapon of the near future is what’s known as a hypersonic glide vehicle, sometimes called a “wave rider,” because its aerodynamics allow the winged projectile to skip along the atmosphere, or glide on a smooth, flat trajectory after being launched via missile.