THE US Navy has a raygun - and it's a big one.

In a red-letter week for the US military, its Naval Sea Systems command "successfully tracked, engaged, and destroyed” several unmanned aircraft with its Laser Weapon System, otherwise known as LaWS.

On the ground, iRobot unveiled its gift to the Pentagon - the 710 Warrior designed to clear an entire 45 square metre minefield in one blow.

But first, the raygun.

According to The Register, "it represents the first Detect-Thru-Engage laser shoot-down of a threat representative target in an over-the-water, combat representative scenario".

LaWS is fitted to the Navy's "R2-D2" robotic gun turret and looks every bit like what you'd expect a raygun to look like.

In normal operations, R2-D2 would support the Navy's Phalanx 20mm cannon, which automatically locks onto incoming missiles and blasts them out of the sky.

Unfortunately for anyone in the impact zone, that ususally results in a shower of shrapnel or the 20mm shell itself if it fails to explode.

The LaWS system simply vapourises the target.

Naval spokesman Captain David Kiel said the success test "validates the military utility of (rayguns) in a maritime environment".

"Further development and integration of increasingly more powerful lasers into Surface Navy LaWS will increase both the engagement range and target sets that can be successfully engaged and destroyed," he said.

As for iRobot's Warrior, an extremely convincing video shows how it can roll into a minefield and deploy a set of grenades to clear a large chunk of turf.

iRobot co-founder had previously told Wired that his company wasn't in the business of making weaponised robots, and it's probably sticking to its guns, so to speak.

But obviously iRobot can't tell the US military how to use its devastating metal marine...