Radar Fuzes Would Turn Ukraine’s Glide-Bombs Into Urban Wrecking Balls

A few weeks after the first rumors circulated that the Ukrainian air force would be getting satellite-guided glide-bombs from the United States, a U.S. official has confirmed that, yes, some of the winged Joint Direct Attack Munitions have arrived in Ukraine.

“They have enough to do a couple of strikes,” U.S. Air Force general James Hecker, head of U.S. Air Forces in Europe, told reporters including The War Zone’s Joseph Trevithick last week.

With their 45-mile maximum range, the bombs are a powerful new capability. Especially if the Ukrainians also are getting the best fuzes. Including the 1970s-vintage DSU-33, America’s classic proximity fuze.

Bombs aren’t created equal. The casing matters. The explosives mix matters. The fuze matters, too—a lot.

The basic fuze is an impact fuze with a firing pin or crush switches. When the bomb hits the ground, the impact presses the pin into a detonator or compacts the switches. Boom.

A delayed impact fuze waits a bit after impact so that the bomb buries itself into the ground before exploding. Just the thing to demolish a tunnel, cave or underground bunker.

Then there’s the proximity fuze. Thanks to a tiny radar or some other sensor, the fuze knows when it’s a certain height above the ground—and detonates the bomb in mid-air. A proximity-fuzed bomb is the best way to pepper exposed troops with lethal fragments, or widen a blast zone in order to flatten lightly-built structures.

“An airburst fuze on a conventional munition can increase its area effect by up to 100 percent,” the Geneva International Center for Humanitarian Demining noted.

This area effect is especially important in eastern Ukraine, where the worst fighting takes place in the ruins of towns and cities—and where abandoned homes function as fighting positions, command posts and bivouacs.

In this environment, a 500-pound JDAM-Extended Range with a DSU-33 radar fuze, set to explode 20 feet above the ground, would be like a wrecking ball.

Ukrainian fighter pilots could fly low in order to avoid Russian air-defenses, pitch up as they approach the front line and lob their JDAM-ERs at a high angle. The bombs’ wing pop out and they glide for miles before arcing down and exploding 20 feet over some shell-pocked roof.

It’s dangerous duty for an attacking pilot—but the effect, for friendly troops on the ground, could be worth the risk. “There are tactics where you can go in low and do some things … and get back,” Hecker said.

To be clear, there is no evidence the Ukrainians have gotten DSU-33s for their JDAMs.

There’s no reason they shouldn’t, however. American firms have built hundreds of thousands of the fuzes over the decades. “DSU-33 has been one of the most successful air-weapon fuzing/sensor programs in the last 40 years,” Dave Liberatore, Northrop Grumman’s DSU-33 program manager, said in 2019.

The U.S. Air Force in its 2023 budget proposal is asking for $120 million to, among other things, pay for an improved version of the DSU-33.