The Navy moves closer to the deployment of operational unmanned subs

By GLENN W. GOODMAN Jr., Special Correspondent

A major milestone in the U.S. Navy’s development of autonomous unmanned undersea vehicles (UUVs) occurred in January. The service achieved the first successful at-sea docking of a UUV with a submerged nuclear-powered attack submarine, the USS Scranton.

The submarine docked with Boeing’s Long-Term Mine Reconnaissance System (LMRS), designed to enable submarines to conduct clandestine undersea surveys to locate mines. The tests demonstrated the ability of an attack submarine to launch an untethered, self-propelled, autonomous UUV from its 21-inch-diameter torpedo tubes, rendezvous with it and guide the UUV into a torpedo tube-mounted robotic recovery arm using an acoustic communication system.

The Navy doesn’t plan to produce the single-mission LMRS, but instead is leveraging the lessons learned from it and moving forward to acquire more advanced, reconfigurable, multimission UUVs. Navy Capt. Paul Ims, program manager for UUVs in the Program Executive Office for Littoral and Mine Warfare, said, “Our UUV programs are [now] focused on delivering more affordable, modular, autonomous systems with an open architecture.”

A contract to develop the first of these, called the 21-inch Mission-Reconfigurable UUV System (MRUUVS), is slated for award in mid-2007, and the UUV could become operational in 2013. An open architecture, or general blueprint, for computerized combat systems means they are standardized, transferable to other platforms and able to accommodate a variety of software applications. 

The Navy plans to operate some existing, less-sophisticated UUVs from its forthcoming Littoral Combat Ships, particularly to hunt for mines, using surface launch and recovery. These include the 10-foot Battlespace Preparation Autonomous Underwater Vehicle developed by the Office of Naval Research and Bluefin Robotics of Cambridge, Mass. The ships are being designed to counter shallow-water threats in coastal areas, such as mines, diesel submarines and fast surface craft.

However, the major beneficiary of the new UUVs slated for development may be the Navy’s nuclear-powered attack submarine fleet. UUVs promise to bring about a significant transformation in the submarine force that will extend and expand its operational capabilities, particularly for clandestine underwater intelligence, surveillance and reconnaissance (ISR). UUVs will extend the covert sensor range of manned submarines, go into high-risk or inaccessible areas, and provide timely clandestine knowledge of the battlespace.

The service’s November 2004 UUV Master Plan cites ISR as the Navy’s top UUV priority, followed by mine countermeasures, and then antisubmarine warfare as a longer-term priority.

A key purpose of the Master Plan was to help the Navy organize and consolidate its various UUV efforts, which in late 2004 included some 70 vehicles of different lengths, widths and configurations. The plan stressed the need for commonality in components and interface standards, modularity and open-architecture designs among new UUVs to reduce costs.

The Master Plan identifies four vehicle classes of increasing size and capability — Man-portable, Light Weight, Heavy Weight and Large. The most significant new UUV development efforts will occur in the Heavy Weight and Large vehicle classes.

Designed for torpedo tube launch and recovery, the Heavy Weight vehicles are those 21 inches in diameter and weighing up to 3,000 pounds. Depending on the weight of their sensor payload, their endurance could range from 20-80 hours. They include the 21-inch MRUUVS, which will be launched and recovered by Los Angeles-class and Virginia-class attack submarines.

The Navy plans to move into the Large vehicle class of UUVs in 2010 by beginning development of a large-displacement MRUUVS, which could be 3 to 5 feet in diameter or even rectangular in shape. Weighing around 20,000 pounds, the large-displacement vehicles would offer much greater range, time on-station and payload compared with the 21-inch MRUUVS.

Able to operate autonomously for up to three weeks, the large-displacement vehicles could be launched from the 7-foot-diameter, 40-foot-long, vertical ballistic-missile tubes of the four Trident submarines the Navy is converting into guided-missile attack subs, or from Virginia-class attack subs or Littoral Combat Ships.

The Navy has a phased development strategy for its Heavy Weight and Large classes of UUVs, moving from the LMRS and an Advanced Development UUV test bed to the 21-inch MRUUVS and subsequently the large-displacement MRUUVS.

Boeing Advanced Information Systems, Anaheim, Calif., won the LMRS development contract in late 1999 and delivered an engineering development system with two 20-foot-long UUVs in late 2002. January’s successful at-sea docking test concluded the LMRS effort.

The operating concept for the LMRS illustrates, in general, how the 21-inch MRUUVS will be used. It called for the lithium battery-powered vehicle to be equipped with a forward-looking search sonar and a side-scanning mine-classification sonar to survey suspected minefields. These would allow it to identify mines in shallow coastal waters or at depths down to 1,500 feet.

After it was projected out of a torpedo tube, the autonomous UUV would search a preprogrammed area. Every nine to 12 hours, it would come to the surface to get a Global Positioning System satellite location fix and signal back to the submarine via radio where it had been and the location of mine-like contacts it found. The UUV also would receive instructions from the submarine if there were a change in the area to be searched.

It would repeat that process every nine to 12 hours until its 40-50-hour sortie was completed. It would then rendezvous with the submarine, which had been free to conduct other missions, and be recovered back into a lower torpedo tube using a 60-foot robotic arm extended from the upper torpedo tube above it.

Ims said that while LMRS docking with Scranton was achieved in January, the UUV could not be fully recovered back into the submarine as planned.

Rear Adm. William Landay, then the program executive officer for Littoral and Mine Warfare and now the chief of naval research, told Seapower in an October 2005 interview before the testing that pulling the LMRS back into a torpedo tube had been problematic.

In May 2003, the Navy awarded Lockheed Martin Maritime Systems & Sensors, Riviera Beach, Fla., a contract to design a single prototype Advanced Development UUV as a technology risk-reduction precursor effort for the 21-inch MRUUVS. The prototype is the first designed to accommodate interchangeable modular payloads that can be swapped out at sea for various missions.

“The purpose of the [prototype vehicle] was to demonstrate that we really can build a modular vehicle, where each module stands on its own,” Ims said.

A Lockheed Martin brochure states the prototype program “has been successful in demonstrating the promises of modularity for cost savings and mission reconfigurability and addressing key issues for 21-inch MRUUVS development.” The prototype, which has been undergoing underwater testing, will serve as a test bed for future UUV payloads.

For example, in January the Navy awarded Lockheed Martin a 20-month contract modification to integrate the advanced Littoral Precision Underwater Mapping Array sensor into the advanced development prototype and test it at sea. Developed by the Applied Research Laboratory in Austin, Texas, the new sensor provides precise three-dimensional obstacle detection/classification and deep-water sea bottom mapping capabilities as well as cutting-edge acoustic communications.

It would allow a UUV to “rapidly change its mission from mine countermeasures to ISR,” Lockheed Martin said in a release. The littoral precision sensor is expected to be government-furnished equipment on the 21-inch MRUUVS.

The 21-inch MRUUVS initially will perform “autonomous clandestine mine countermeasures and ISR missions at significant standoff distances,” Ims said. “That’s the big difference between it and other types of UUVs we’re putting on surface ships. The 21-inch MRUUVS has a need for long legs, with a lot of propulsion capability.”

It will augment the capabilities of its host submarine, leveraging the sub’s mobility and dwell time and extending its stealth and sensor reach into operating areas that are not otherwise accessible due to very shallow water or minefields, he said. The 21-inch MRUUVS also will “complement the host submarine’s sensors to enable simultaneous coverage at multiple sites, particularly for ISR,” Ims added.

Milestone B development approval for the program is scheduled for late this year or early next year.

“We are focused on this program for the future,” he said. “We’re going to take it through the acquisition path and then put it in the fleet.”

The large-displacement MRUUVS will be a “truck” that could haul a variety of payloads.

“We’re still studying our requirements” for it, Ims said. “Those will be much more demanding than the ones for the 21-inch MRUUVS. It must be able to operate autonomously for weeks. We’re looking hard at answering the questions, ‘What should be the specific missions for the initial version?’ and ‘Where should we focus our attention?’

“We could build a large UUV today and pack lots of batteries in it to give it plenty of endurance. The challenge would be the autonomy to make that vehicle capable of being a warfighting machine.”

Ims emphasized the importance of taking a system perspective rather than a vehicle-centric approach in the development of the 21-inch MRUUVS.

“This is a system. It’s not the vehicle that is the hard part. LMRS has run great, and the Battlespace Preparation Autonomous Underwater Vehicle has done a great job. But we can’t just focus on the vehicle. It’s one thing to conduct a developmental test and demonstrate a capability in a limited set of circumstances,” he said.

“The issue is the UUV system, which has to be integrated on a warship, has to be highly reliable and has to be readily operated by sailors in combat. I’ll suggest that no company has achieved that yet.”