Navy eyes drone ‘Mothership’ to launch smaller sea-based drones

As the Navy moves forward with plans for a fleet of unmanned surface vessels that will integrate with and augment its conventionally manned ships, it’s asking industry about the feasibility of a new class of attritable drone “motherships” that could operate in a variety of sea states and serve as a communications hub and launch platform for smaller drone vehicles.

According to a solicitation released at the end of October, the notional “Attritable UxV Mother Ship,” or AUMS, would be able to carry or tow a 20-foot shipping container from which unidentified drone platforms could deploy. If the container is carried aboard the mothership, it must also be equipped with a system to push it over the side, the solicitation states. While the description of this vessel as “attritable” indicates it would be relatively low-cost, the Navy wants AUMS to last at least five years. The design, according to documents, should incorporate modular open architecture so that the platform can be updated to feature the latest technology during mid-life maintenance.

“Longer service life is desired if attainable for a very small increase in procurement cost,” the description adds.

A view of an unmanned surface vehicle (USV) being brought aboard Military Sealift Command’s expeditionary sea base, USNS Hershel “Woody” Williams (T-ESB 4), after the ship’s crew launched it into the Chesapeake Bay, Sept. 14, 2019. The USV is a mine countermeasure platform and the evolution was the first time a USV has been launched and recovered by a Military Sealift Command ship. (U.S. Navy photo by Bill Mesta/Released)

The AUMS class would include a lead ship and up to 10 additional vessels, with a design and construction contract to be awarded sometime in fiscal year 2026.

The Navy wants to get the boats fast, asking that the first vessels be delivered to the fleet within two years, if it can be done affordably. The service is willing to use an existing commercial manned or unmanned ship design for AUMS, but it’s also open to considering a clean-slate design if it serves the Navy best.

“Cost containment is the single most important goal of the AUMS design and approach,” officials said in the document.

The drone mothership should be built to cross 1,500 nautical miles, or more than 1,700 land miles, across open ocean, with the potential of expanding that transit distance to 2,000 miles or more. It needs to be capable of operating for up to five days in a fully unmanned state, over the horizon from manned Navy ships. It should be reasonably swift, with top speeds between 12 and 20 knots, or 13 to 23 miles per hour. By comparison, a U.S. Navy destroyer can hit top speeds of 63 knots, and a carrier, 30 knots.

A rugged drone mothership for the Navy’s open ocean operations

After launching, the mothership would make its way to the open-ocean drop-off location, where it would jettison its shipping container containing unmanned vessels. The container, the solicitation adds, would then be self-sustaining.

The Navy’s still evaluating navigation and communications mechanisms for AUMS; documents say it should be capable of GPS navigation and following waypoints, but with systems that provide for continued operations if GPS signal is lost. The platform may also have over-the-horizon and line-of-sight communications mechanisms so that human monitors can track it and provide additional taskers as it transits to its destination.

“AUMS should be designed to minimize the chances of collision with other vessels, and/or minimize damage to other vessels if a collision were to occur,” the solicitation states. “The trade space of how to achieve this should be explored.”

SAN DIEGO (April 12, 2016) Members of Maritime Tactical Systems lower a Man-portable Tactical Autonomous System (MANTAS) into the water during a demonstration at Naval Base Point Loma. The MANTAS unmanned vehicle system will enable surface and sub-surface coverage over wider areas and is specifically designed for multi-role autonomous unmanned operation. (U.S. Navy photo by Mass Communication Specialist 2nd Class Travis Litke/Released)

While it’s not clear what this vessel would be made of, it’s got to be somewhat rugged. The Navy wants potential manufacturers to report on the cost of making it “survivable” in conditions up to Sea State 6, which entails large waves of up to nine feet.

Likely based on a commercial ship template rather than a military one, AUMS wouldn’t have any weapons, but it would be equipped with more passive defensive capabilities, including a 360-degree camera, mechanisms to resist boarding and tampering from intruders, and a “self-scuttling capability” that would allow Navy to sink the ship remotely if it became compromised.

Drone ships are taking on the oceans

BVT’s drone carrier concept. (Wikimedia Commons via BAE Systems Maritime Naval Ships)

This new solicitation highlights the Navy’s continued efforts to develop relatively cheap unmanned platforms that can fall in with the service’s demand for global operations and for presence in environments with vast stretches of open ocean, like the South Pacific and the Philippine Sea.

The idea of a UXV mothership is not completely new: in 2007, well before the Navy had launched its Ghost Fleet Overlord unmanned surface vessel program, the company BVT Surface Fleet (now BAE Systems Maritime Naval Ships) debuted a “drone carrier” concept. The UXV combatant, as it was called, was equipped with 155mm cannons and a short flight deck capable of launching manned or unmanned aircraft.

Smaller-scale variations have also been pitched. In 2018, maritime company Mauric revealed its Octopoda 500 concept: an unmanned offshore patrol vessel built to deploy a range of drones – surface, undersea, or aerial – for mine countermeasures or surveillance operations.

The Octopoda 500 unmanned offshore patrol vessel. (Mauric)

Meanwhile, the Navy’s investments in its planned drone fleet are steadily growing. The pending fiscal 2023 budget calls for nearly $550 million in research-and-development and core technologies funding for the two main unmanned surface ship platforms the Navy wants to build. These include Medium and Large Unmanned Surface Vehicles, ranging in size from 50 to 300 feet in length.

“The Navy wants to acquire these large UVs as part of an effort to shift the Navy to a more distributed fleet architecture, meaning a mix of ships that spreads the Navy’s capabilities over an increased number of platforms and avoids concentrating a large portion of the fleet’s overall capability into a relatively small number of high-value ships (i.e., a mix of ships that avoids ‘putting too many eggs into one basket’),” a Congressional Research Service briefing document on the topic states.

The Navy’s newest force design plan, released earlier this year, calls for a mix of 150 unmanned vessels and 373 manned ships by 2045.

According to the solicitation, interested companies have until December 15 to answer the Navy’s call for drone mothership proposals.