Leidos Inc. is carrying out a range of tests of sensors and command-and-control systems planned for integration on board the Sea Hunter, a 132-foot ship the company has built that will operate autonomously to conduct antisubmarine warfare (ASW) and possibly other Navy missions.
In late 2012 Leidos, then SAIC, won a Defense Advanced Research Projects Agency (DARPA) contract under DARPA’s Antisubmarine Warfare Continuous Trail Unmanned Vessel (ACTUV) program to develop and build an autonomous trimaran for the ACTUV mission. DARPA had awarded concept exploration contracts to SAIC, Northrop Grumman, and QinetiQ earlier, expecting the teams to propose unmanned semisubmersible vessels to counter extremely quiet diesel-powered submarines.
The ACTUV is required to deploy for 60 to 90 days without needing maintenance nor human control.
SAIC reorganized in September 2013, resulting in the establishment of Leidos, which retained SAIC’s national security programs.
Dave Antanitus, senior capture manager for Leidos, said that “We didn’t take it on faith that the best platform would be a semisubmersible, which is essentially like a submarine at periscope depth.” Instead, the company proposed a trimaran, a central hull supported by outrigger pontoons, and won the contract for three follow-on phases: design, construction, and government testing.
Following DARPA approval of the design in early 2014, Leidos teamed with Oregon Iron Works (OIW) for construction of the ship. OIW subcontracted the work to Christensen Shipyard of Vancouver, Washington. Leidos subsequently decided to transfer construction of the ship to Vigor Shipbuilding in Portland, Oregon; Vigor acquired OIW in May 2014.
In September 2014 DARPA and the Office of Naval Research (ONR) signed a memorandum of agreement transferring management of the program to ONR in January 2017, whereupon ONR would fund two additional years of testing. DARPA and ONR collaborated on overseeing delivery of the ship.
While ASW still is the primary ACTUV mission, the Navy also could consider employing the ship as an “autonomous truck” for other “dull, dirty, and dangerous roles,” such as intelligence-gathering and mine countermeasures, Antanitus said.
The Sea Hunter is built with lightweight composite materials and displaces 145 long tons. She is powered by twin MTU diesel engines and twin Caterpillar diesel generators, which drive twin propellers and a bow thruster for maneuverability. Maximum speed is around 26 knots.
“Sea Hunter has extremely long legs,” said Antanitus He pointed out that, at eight knots, she can transit from San Diego to Sydney, Australia, and back, and then to Yokosuka, Japan, without refueling, and still have enough fuel to steam another 1,243 miles.
The real science behind the Sea Hunter is autonomous navigation. The ship is fitted out with a prototype autonomous navigation system, S- and X-band radars, a frequency-modulated continuous-wave radar, global positioning and inertial navigation systems, and a weather station. The systems use only commercially developed technology.
To demonstrate the performance of the autonomy system while the Sea Hunter was under construction, Leidos conducted some 22,000 laboratory scenarios developed by deck-qualified officers encompassing cruising, crossing, overtaking, and other maneuvers. The company then installed the prototype autonomy system aboard a “surrogate” vessel, a 42-foot Munson workboat, designated Pathfinder, and, after interfacing the system with the boat’s autopilot, ran more than 100 in-water test events.
For further risk reduction, Pathfinder used the autonomy system to transit the heavily used 35-mile sea route from Biloxi to Pascagoula, Mississippi, and back to Biloxi. On the trip, using only the autonomy system, digital charts, and GPS coordinates of the starting point and destination, Pathfinder maneuvered successfully to avoid other ship traffic, submerged hazards, shoal water, buoys, and other potential obstacles.
Although some personnel were on board to observe, the vessel used the autonomy system exclusively for the entire duration of the voyage, Antanitus said.
The Sea Hunter was launched in early 2015 and commenced builder’s trials in the Columbia River. The ship was christened in Portland this past April.
Speaking at the Sea Hunter christening, Deputy Secretary of Defense Robert Work said, “How often can you be at the christening of a robot warship . . . you’re going to look back at this day just like . . . when the USS Nautilus was christened, or when the USS Enterprise was commissioned, or when the DDG-1000 was commissioned, our first stealth battleship. And you are going to look back on this and say, ‘I was part of history.’”