The Defense Department christened the Sea Hunter, a 132-foot robot ghost ship designed to seek out and track diesel-powered submarines across the ocean. The start of the test phase for the program on Thursday signals a new dawn for autonomous systems at sea, which, Pentagon officials say, will perform an ever-wider variety of jobs and could fundamentally change the way militaries operate on the water.
The Sea Hunter is the first of a new type of ocean drone, called an Anti-submarine Warfare Continuous Trail Unmanned Vessel, or ACTUV. The goal of the program: field an autonomous ship with the range and endurance to go anywhere in the world while avoiding collisions with other ships and obeying the rules of navigation. “Current unmanned surface vessel systems and concepts are operated as close-adjuncts to conventional manned ships – they are launched and recovered from manned ships, tele-operated from manned ships, and are limited to direct support of manned ship missions. The ACTUV system will be a first of its kind unmanned naval vessel that is designed and sized for theater or global independent deployment,” reads the program’s description from 2014.
Below is footage from some ACTUV trial runs. The vessel can travel 27 knots and was designed to stay at sea for as long as 70 days, but the actual voyage duration depends on fuel burn.
Although the ship is designed to sail unmanned, a human operator will maintain contact and make sure the ship is obeying nautical rules and is on mission. “The human being is not joysticking,” said DARPA program manager Scott Littlefield. Rather the operator stays in the loop via what DARPA calls sparse remote supervisory control. The ship perceives its environment via F- and X-band radar, the ship automatic identification system (required on ships of greater than 300 tons), and a camera. DARPA is working with the Office of Naval Research on a stereoscopic camera and software that can do advanced image recognition of other ships that it encounters. If a second vessel meets ACTUV on the open sea and needs to make bridge-to-bridge contact, the remote human operator will do the talking.
ACTUV is designed to track the new, quieter generation of diesel-powered submarines, a rising concern for the Pentagon, and with a price tag between $200 million and $300 million they are proliferating. Iran currently has 17 diesel attack submarines; China, 53. “Some observers raised questions about the Navy’s ability to counter Chinese submarines,” according to the Congressional Research Service, or CRS. Cases in point: in 2006, a Chinese Song sub surfaced five miles from the aircraft carrier USS Kitty Hawk. And last October a Chinese attack submarine trailed and simulated a missile attack on the carrier USS Ronald Reagan off the southern tip of Japan.
These sorts of incidents are where ACTUV could help close a critical gap. And there are other sea monsters out there, including mines.
Responding to a variety of threats will require different modules and sensor payloads on the ACTUV, which DARPA is exploring with the ONR. Just days before the christening, Matt Klunder, a retired rear admiral and former ONR chief, was at the Pentagon discussing work that the company Harris, where he now serves as vice president for Defense Department strategy, is doing in new sensor payloads and what they mean for future autonomous vessels.
“Now we’ve also got these incredibly small micro-payloads that we can put on these autonomous platforms that make them unbelievably effective in terms of a multitude of missions for the Navy, Marine Corps, Army, Air Force, pick one. It’s really given us an ability to now scale these autonomous platforms into many, many multi-function missions,” Klunder told Defense One .
Klunder spearheaded autonomy research at ONR. During that time ONR developed the Control Architecture for Robotic Agent Command and Sensing, or CARACaS, a small cube not much bigger than a paperweight that with a few other modifications can turn any boat into an autonomous vessel. That led to a key demonstration of next-generation swarming capability on the James River in 2014. Some 13 small, rigid-hulled inflatable, or RHIB, boats were outfitted with CARACaS and showed the ability to conduct coordinated maneuvers in defense of a ship.
“Now we’ve got these micro-payloads down to the size of my hand, literally. So now I can stack many, many multi-function capabilities,” he said, “There are electronic capabilities that you could put on that ghost ship, as you like to call it. Now, think about not just one of them, but potentially more than one of those ACTUV ghost ships on the blue water, potentially with a number of different mission payloads. You might have something that would be very intriguing and make our adversaries very concerned.”
Autonomy, the Navy Way
It is this unique approach and embrace of autonomy that in many ways separates the Navy from the other services. Air Force leaders, for instance, are allergic to the terms “drone” and unmanned vehicle, preferring instead “remotely piloted aircraft,” or RPA. They take great pains to remind the press of all the manpower that goes into a combat air patrol with a nominally unmanned Reaper or Predator. A ground crew launches the drone, a second crew, often out of Creech Air Force Base, in Nevada, takes over the mission in flight. There’s a pilot, a sensor operator, and data analysts all watching carefully. “For every RPA combat air patrol there are nearly 200 people supporting the mission in various capacities,” U.S. Air Force public affairs said last year, as though this inefficiency were an asset.
Many Navy leaders, meanwhile, have recognized that autonomous vessels, whether specifically designed or retrofitted, aren’t just a part of future naval dominance, they are key. “You can listen to the senior leadership in the Pentagon today, there are so many dynamic and troubling hot spots around the globe now, it’s not just one or two places, it’s everywhere,” says Klunder. “I would almost offer to you that they need these low cost numerous, autonomous vehicles and platforms to keep our nation and our partners’ national security safe. You cannot do it with just these exquisite, specialized platforms. We do need them in very high risk scenarios but I will also tell you that because we need to be all over the globe all the time to combat terrorism and extremist forces and to keep our partner’s secure, we absolutely need the ability to convert these existing platforms to very effective war-fighting capabilities with autonomy and with micro-payloads.”
One of the more controversial of those expensive, exquisite platforms is the littoral combat ship, or LCS. At $440 million per ship, it can modified for submarine hunting, mine clearing, and escorting larger valuable ships. But for all the cost, and recently announced improvements to the ship’s armoring and guns, the LCS is not well-defended against Chinese anti-ship cruise missiles. Many of the primary jobs that the Navy is envisioning for the LCS are all tasks that the ACTUV, with a target cost of around $20 million per unit, might do as well.
That doesn’t mean the Navy can, should, or would scrap the LCS and swap in ACTUVs as a substitute. But there are many cases where a robotic vessel can provide that coverage.
Without acknowledging the LCS directly, Littlefield spoke to the price comparison between ACTUV and other ships. “When you put people on a ship and send them into harm’s way you’ve got to do a lot to protect them. One of the benefits that a vessel like ACTUV brings is it reduces the requirement for survivability features that are primarily there to protect the crew,” said Littlefield. That “potentially allows you to build a smaller and less costly vessel and also potentially put it in situations where you would not be willing to put a manned vessel. ACTUV isn’t exactly expendable but in all out war… it would be okay to lose some of these if, as part of the overall campaign, if it reduced the threat to your manned ships,” he said.
He added that, ACTUV, as a government-owned vessel, is still covered by sovereign immunity, an attack on ACTUV would be a “provocative act.”