The Pentagon has a long-standing policy of not publicizing hypersonic missile tests before they happen, except for safety notices for civilian airplanes and ships downrange. But the Defense Department declared the previous Dark Eagle test flight a success within a few hours of the launch, and did not do so this time.
Hypersonic missiles offer several advantages over conventional ballistic missiles. These new kinds of weapons are more maneuverable and dimmer than other missiles, so they are more difficult for an aerial defense system to detect, track, and destroy. They are designed to evade an adversary’s missile warning sensors. These sensors were originally activated to detect larger, brighter incoming ballistic missiles, which have a predictable trajectory toward their targets after boosting themselves out of the atmosphere and into space.
A hypersonic weapon is different. It can skim through the upper atmosphere at blistering speeds, producing a much dimmer heat signature that is difficult to see with an infrared sensor on a conventional missile warning satellite. At these altitudes, the glide vehicle can take advantage of aerodynamic forces for maneuvers. This is why the Pentagon’s Space Development Agency is spending billions of dollars to deploy a network of missile tracking satellites in low-Earth orbit, putting hundreds of sophisticated sensors closer to the flight path of hypersonic weapons.
Dark Eagle is designed to fly at speeds exceeding Mach 5, or 3,800 mph, with a reported range of 1,725 miles (2,775 kilometers), sufficient to reach Taiwan from Guam, or NATO’s borders with Russia from Western Europe. The US military says it has no plans to outfit its hypersonic weapons with nuclear warheads.
In a statement on Thursday, the Department of Defense said the weapon’s official name pays tribute to the eagle, known for its speed, stealth, and agility. Dark Eagle offers a similar mix of attributes: velocity, accuracy, maneuverability, survivability, and versatility, the Pentagon said.