THE EMERGING TECHNOLOGIES SPEED GAME: YEARS AFTER KICKING OFF, U.S. HYPERSONIC PROGRAMS STILI IN DEVEIOPMENT.

• Author: Hbckmann, Laura

It was some eight years ago in September 2015 when reports emerged that China had tested a high-speed drone called the WZ-8 that was designed to reach hypersonic speeds.

That event was a watershed moment for the Pentagon, which had let U.S. hypersonic research-and-development lapse over the decades as it fought the socalled global war on terror.

Soon after, Russia made its own claims that it had deployed missiles reaching hypersonic speeds, generally defined as more than Mach 5, but with the added ability to maneuver and evade defenses.

The realization that the two competitors were actively pursuing the high-speed, maneuverable weapons prompted the Defense Department to reignite its own R&D programs within the

Army, Navy, Air Force and the Defense Advanced Research Projects Agency.

But eight years after the Chinese test, how much progress has the U.S. military made developing its own hypersonic weapon systems?

"We are in a race whether we choose to acknowledge it or not," said Mark Lewis, chief executive officer of the Purdue Applied Research Institute, at a media event in June.

The Defense Department has focused in recent years on two approaches: glide vehicles and cruise missiles, according to the Congressional Research Service report "Hypersonic Weapons: Background and Issues for Congress," released in February.

Hypersonic boost-glide missiles consist of a rocket motor, which accelerates the missile to a high speed, and a glide body containing a warhead. Once the glide body detaches from the spent rocket, it uses kinetic energy, as well as lift generated by its movement through the air, to coast at high speed through the atmosphere and maneuver to hit its target, according to a description in the report "U.S. Hypersonic Weapons and Alternatives," published by the Congressional Budget Office in January.

A rocket booster initially accelerates a hypersonic cruise missile to speeds approaching Mach 4, then boosts and maintains a higher speed throughout its flight using a jet engine called a supersonic combustion ramjet, or scramjet, that can take it toward Mach 5.

Hypersonic missiles are launched one of three ways: from the air via aircraft in flight, from the ground via fixed or vehicle-based launchers and from the sea, via surface ships or submarines.

The Army is striking from the ground. Partnered with the Navy, the service is developing the Long-Range Hypersonic Weapon.

The weapon is a ground-launched boost-glide missile, equipped with a...