Army Tests Laser Against Mortars And UAVs

By Graham Warwick
Source: Aviation Week & Space Technology

Bauer says the RELI laser is slated to be ready in fiscal 2016, with integration into the HEL MD and testing against mortars, rockets and unmanned aircraft planned for fiscal 2017. A follow-on effort would increase power to 100 kw, further extending range and reducing lasing time to defeat targets.

In the latest tests, the HEL MD “killed a large number of 60-mm mortars,” says Mike Rinn, Boeing vice president for the Directed Energy Systems division. The 10-kw laser also demonstrated it could the blind the electro-optical sensors on UAVs and it brought down the aircraft by burning off their tails.

Because the off-the-shelf industrial laser, produced by IPG, has limited power, mortars were engaged at less than 2-km (1.2-mi.) range and UAVs at less than 5 km, says Bauer. Success for these tests was defined as putting laser energy on the target, but HEL MD went “above and beyond the criteria,” he says.

“A 60-mm mortar is the size of a football in length, at a range of 2,000-3,000 yards. We demonstrated we could rapidly acquire with radar a small, dim target and guide a beam the size of quarter to destroy that target in flight,” says Blaine Beardsley, Boeing HEL MD program manager. “It's remarkable we could do it over and over. That is what's unique compared with other demonstrations in the past.”

The kill mechanism against mortars is “deflagration, not detonation,” Bauer says. The laser energy heats up the high explosive in the round and causes a low-order explosion that disables the mortar. The round will still continue on its ballistic trajectory and hit its intended target, but not explode. “We turn it into a rock,” he says.

The HEL MD includes a beam director that provides 360-deg. coverage to below the horizon, the Army states. The White Sands tests used a surrogate radar to cue the laser system to targets, but the beam-control system includes its own illumination and ranging lasers. For future tests, the HEL MD's thermal and power subsystems will be upgraded to support the increasingly powerful solid-state lasers.

Operationally, a mobile high-energy electric laser could protect ground forces from rockets, artillery, mortars, cruise missiles and UAVs. The advantage over gun and missile systems is the deep magazine and low cost per shot. Each HEL MD engagement “consumed half a cup of diesel,” says Rinn.

Each laser system could engage only one target at time but, at higher power, engagement times would be just a few sec. “A laser is a serial killer; it takes out targets one at a time,” says Bauer. “We would not deploy one by itself, but a platoon with 3-5 systems would support a forward operating base.”

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