Hypersonic Glide Vehicle (HGV) Dodges Defenses At Hypersonic Speed.

Advanced Hypersonic Weapon Concept Launch Test

Courtesy photo, U.S. Army.  From a November 18, 2011 test.

Secretive D.O.D. Drone Dodges Defenses At Hypersonic Speed.

By Jeffrey Lin and Peter W. Singer. popsci

On August 25, an explosion tore through the southern Alaskan sky. The blast shook the remote island that houses the Kodiak Launch Complex, where the U.S. Department of Defense was testing an unmanned hypersonic glide vehicle (HGV). The flight of the highly secretive craft lasted a mere four seconds before an “anomaly” in the launch rocket forced controllers to deploy the emergency self-destruct mechanism.

Upon discovering the location of a terrorist leader in Syria, an HGV fired from an Army base in Europe could hit the target in less than half an hour.

The launch, the latest in a series that began in 2011, was saddled with added pressure: China has reportedly carried out at least two hypersonic tests this year (though both also ended in flames). The two nations are racing to engineer a vehicle capable of traveling faster than 10 times the speed of sound, which presents major obstacles. Such a craft requires materials that can withstand temperatures over 3,500°F and a steering system sensitive enough to maneuver through the thin air of the upper atmosphere.
The details behind the U.S. and China’s HGV programs remain confidential, but that real-world tests—however spectacular the crashes—are taking place indicates that the vehicles have crossed into the realm of the possible. Experts anticipate that HGVs could be fully operational as soon as 2019 and reach speeds up to Mach 25, or about 16,000 miles per hour.
If weaponized, HGVs could fly as far as intercontinental ballistic missiles (more than 3,500 miles) but strike with greater accuracy. Since the gliders don’t fly in a predictable parabolic arc like ballistic missiles do, they would be exceedingly difficult to shoot down with traditional missile defenses. And their speed would make possible a whole new pace of war. For example, upon discovering the location of a terrorist leader in Syria, an HGV fired from a U.S. Army base in Western Europe could hit the target in less than half an hour.

Hypersonic Glide Vehicle. Graham Murdoch

Approximated HGV flight (designs not yet released) based on tests of existing experimental aircraft

How It Flies

1. Launches via rocket boosters that detach in the upper atmosphere
2. Descends to an altitude of about 50 miles and then pulls up to level off its course
3. Glides along an unpredictable path, veering left and right to avoid defenses
4. Dives downward to hit its intended mark
5. Destroys its target with explosives or the vehicle's kinetic energy alone