Northrop Grumman unveils prototype of spooky new underwater drone

A full-size prototype of Manta Ray, a new uncrewed underwater vehicle, is assembled in Northrop Grumman’s Annapolis facility. The company, which has several Utah locations, is developing the Manta Ray to study the ocean for long periods of time, using the ocean to generate electricity. (Northrop Grumman)

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SALT LAKE CITY — Northrop Grumman has released images of a completed prototype for a new class of autonomous underwater vehicles, as part of the Manta Ray project.

Monday's release marks a major milestone after two companies were awarded prime contracts in 2020 to build the equivalent of drones, or maybe Roombas, but for underwater use, while finding new ways to harness the ocean's energy.

Northrop is the largest private sector aerospace and defense employer in Utah, with locations in Brigham City, Clearfield, Magna, Ogden, Roy, Tremonton and Salt Lake City.

A far cry from the powerful solid-state rockets tested in Promontory in Box Elder County, the contract calls for "low-power, high-efficiency undersea propulsion systems," and low-power methods of sensing the vehicle's surroundings while remaining undetected, requiring that these vehicles remain independent of existing ports or ships after deployment.

Like a lunar rover operating alone on the surface of the moon, these vehicles would wander the ocean floor, anchoring in place to "sleep," before continuing their patrols and payload deliveries.

The aquatic-looking glider is built to conduct long-range missions, remaining underwater for extended periods. With that, comes serious engineering challenges, which have required new technology. Materials in the ocean must combat "biofouling, corrosion and other material degradation," according to the Defense Advanced Research Projects Agency, which awarded the contracts.

The two companies named prime contractors, Northrop Grumman Systems Corporation and Martin Defense Group, are each developing their own full-scale demonstration vehicles. Each is opting to use wildly different methods for recharging in the ocean. Northrop was given over $41 million, and Martin was awarded almost $55 million.

In 2022, Northrop reported receiving $31.3 billion in government awards.

Artist’s concept of Northrop Grumman’s unmanned underwater vehicle, Manta Ray.
Artist’s concept of Northrop Grumman’s unmanned underwater vehicle, Manta Ray. (Photo: Northrop Grumman)

Northrop has partnered with Seatrec, a renewable-energy technology company, to "extract energy from the ocean's thermal gradient — the difference in temperature between warmer mixed water near the surface and colder water below — and convert it to electricity," according to its website.

Northrop's system looks to create stations in the ocean, where these vehicles could dock and recharge, transfer their collected data before departing again. A ship would deploy a pod that anchors itself to the sea floor.

"Once in place, its thermal energy harvesting pod will begin propelling itself up and down a cable through the thermocline, generating and storing electricity," Northrop engineer Brian Theobald explained in a statement. "Within a few days, it will have generated enough energy to begin servicing autonomous rechargeable systems."

To transmit data back to real people, Theobald said the station would release little electronic devices, called "data bubbles," that would float to the surface and use little antennas to transmit data to a satellite, ship or port.

Martin's vehicle is likely using an underwater kite, which uses the motion of the water to generate its power. The company partnered with North Carolina State University's Mechanical and Aerospace Engineering Department, which recently invented a device made of liquid metal, encased in a hydrogel that produces electricity when it is stretched. A university statement said, "The kite can harvest significantly more power per unit area than a conventional turbine through controlled power-augmenting cross-current motion."

The Navy has been investing in fleets of large and small underwater vehicles to, "among other things, covertly deploy the Hammerhead mine, a planned mine that would be tethered to the seabed and armed with an antisubmarine torpedo," according to a congressional report.


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