Introduction:
In an era where technological prowess is key to maintaining military supremacy, the United States Navy (USN) is orchestrating a transformative shift in its maritime strategy. Focused on gaining decisive warfighting advantage in anti-access and area denial environments, the USN is steering towards an integrated hybrid force of manned and unmanned systems.
One such innovation that promises to reshape the landscape of underwater operations is the DARPA Manta Ray project. This initiative is focused on the development of a new class of Unmanned Underwater Vehicles (UUVs) with the capability to carry substantial payloads and execute long-endurance missions, ultimately supporting persistent operations beneath the ocean’s surface.
Evolving Naval Vision
The US Navy envisions naval platforms that are not only agile, fuel-efficient, and flexible but are also capable of operating cost-effectively across diverse environments. The integration of both manned and unmanned systems is seen as the key to seamlessly navigating hostile environments while enhancing the Navy’s ability to avoid, defeat, and survive attacks.
Global Landscape: China’s Advances in UUV Technology:
- China’s Autonomous Underwater Vehicle (HSU001): Recognizing the strategic importance of UUV technology, China has also made substantial strides in this domain. The unveiling of the HSU001 marked a significant development, showcasing China’s commitment to large-scale UUV programs designed for covert military operations.
- Undersea Drone Shaped Like a Manta Ray: China’s innovative approach extends to the design of an undersea drone shaped like a manta ray. This bio-inspired design aims for efficiency in underwater movement, utilizing the manta ray’s shape and motion to glide through the water with high propulsion efficiency, mobility, and stability. The unnamed UUV is modeled on the “shape and motion” of a manta ray, and can “flap its wings and slide underwater” like a real ray, per Xinhua. It explains that the rays are the ocean’s “most efficient swimmers,” and are known for “high propulsion efficiency, high mobility and stability, low noise and large load capacity.”
The Need for Innovation:
Shift to a More Distributed Fleet Architecture: Looking ahead, the US Navy is keen on developing and procuring three types of large unmanned vehicles—Large Unmanned Surface Vehicles (LUSVs), Medium Unmanned Surface Vehicles (MUSVs), and Extra-Large Unmanned Undersea Vehicles (XLUUVs). This shift is part of a broader effort to transition to a more distributed fleet architecture.
Large Underwater Drones for Undersea Reconnaissance: Under this strategy, the USN is actively developing large underwater drones designed for undersea reconnaissance. These drones play a pivotal role in sharing critical combat data with submarine “motherships,” hunting for and neutralizing mines, and, in some cases, launching attacks on enemy vessels.
Large Displacement Unmanned Underwater Vehicle (LDUUV) Program: At the forefront of this initiative is the Large Displacement Unmanned Underwater Vehicle (LDUUV) program. This program aims to design, fabricate, and deploy a new class of highly autonomous UUVs. These vehicles boast increased endurance, extended range, and the capacity to host diverse payloads, marking a significant leap forward in undersea capabilities.
As the demand for persistent surveillance and data collection in the underwater domain grows, traditional UUVs face limitations in terms of payload capacity and mission duration. The DARPA Manta Ray project addresses these challenges head-on, aiming to push the boundaries of what is possible in underwater exploration and defense applications.
Manta Ray Program Objectives:
The US Defense Advanced Research Projects Agency (DARPA) launched a programme in 2019 designed to develop a new class of future unmanned underwater vehicles (UUVs) that are capable of both long duration missions and large payload capacity.
“Today’s payload-capable UUV operations are generally limited to shorter duration missions due to propeller‐driven propulsion powering requirements and a fixed battery capacity,” it said, adding that energy capacity limitations “typically couple existing UUVs to manned host platforms, larger UUVs, or ports for periodic recharging”.
DARPA’s Manta Ray Program is a multi-phase effort aiming to demonstrate critical technologies for a new class of long-duration, long-range, payload-capable UUVs. The program is characterized by a disciplined systems engineering approach, with a focus on at-sea demonstrations of key technologies.
Manta Ray Program
The next-generation UUV, known as the Manta Ray, is intended to provide operational commanders with expanded capacities without disrupting current operations by remaining independent of manned vessels and ports once deployed. UUVs that operate for extended durations without the need for on-site human logistics support or maintenance offer the potential for persistent operations during longer term deployments. And they could be acquired and supported at a significantly reduced cost compared to current UUV types.
A secondary goal of the program is to advance key technologies that will benefit other naval designs such as low lifecycle cost UUV operations, long duration undersea energy management techniques, biofouling reduction technologies, and long duration navigational enablers. According to DARPA, specific capability areas of interest include novel energy management techniques for UUV operations, innovative low‐power means of underwater threat detection and classification, and mission management approaches for extended durations while accounting for dynamic maritime environments.
The Manta Ray program plans to advance key technologies that will benefit future UUV designs, including, but not limited to new energy management and energy harvesting techniques at operationally relevant depths; low-power, high-efficiency propulsion; and new approaches to mitigate biofouling, corrosion, and other material degradation for long duration missions. The program also seeks process improvements, including mission management approaches for extended durations while accounting for dynamic maritime environments; unique methods for leveraging existing maritime datasets and new maritime parameters for high-efficiency navigation; and new low-power means of underwater detection and classification of hazards.
Key Features of DARPA Manta Ray:
- Large Payload Capacity: The standout feature of the DARPA Manta Ray is its ability to carry large payloads. Unlike conventional UUVs, which are often constrained by their size and weight limitations, Manta Ray’s design allows for the integration of diverse payloads, ranging from sensors and communication devices to specialized equipment tailored for specific mission objectives.
- Long Endurance Missions: Another game-changing aspect of the Manta Ray project is its emphasis on long-endurance missions. These UUVs are designed to operate beneath the surface for extended periods, offering persistent surveillance capabilities that are critical for both defense and scientific applications. This extended endurance opens the door to a wide array of mission profiles, from monitoring underwater ecosystems to supporting strategic military operations.
- Versatility in Operations: The versatility of the Manta Ray is a key factor in its potential success. Its adaptability to various mission requirements, including intelligence gathering, reconnaissance, and environmental monitoring, positions it as a valuable asset for both military and civilian applications. The capability to easily switch payloads allows for a tailored approach to each mission, maximizing the effectiveness of the UUV.
- Stealth and Autonomy: Stealth is a crucial element in underwater operations, and the Manta Ray project recognizes this by incorporating features that enhance its ability to operate silently beneath the surface. Additionally, autonomy plays a pivotal role in navigating the complex underwater environment, making these UUVs capable of executing missions with minimal human intervention.
Among the technical themes highlighted by DARPA are low‐power, high efficiency undersea propulsion systems, undersea energy harvesting techniques (at operationally relevant depths), new approaches to mitigate biofouling, corrosion, and other material degradation during long duration missions, and innovative means to leverage existing maritime data and exploit novel maritime data for high‐efficiency navigation and/or communications. These also include novel energy management techniques for UUV operations; low-power, high-efficiency propulsion systems; innovative low-power techniques for underwater detection and classification of hazards, and counter-detection of threats.
Potential Applications:
The applications of the DARPA Manta Ray are broad and impactful:
- Military Operations: The Manta Ray’s large payload capacity and long endurance make it a valuable asset for military operations. From strategic reconnaissance to covert surveillance, these UUVs have the potential to transform how navies approach underwater defense.
- Scientific Exploration: Scientists can leverage the Manta Ray for in-depth studies of marine ecosystems and underwater geology. Its ability to carry an array of sensors allows for comprehensive data collection, contributing to a deeper understanding of our oceans.
- Environmental Monitoring: Addressing environmental concerns, the Manta Ray can be deployed for monitoring pollution, tracking marine life migrations, and assessing the impact of climate change on underwater ecosystems.
Key Technologies and Awards:
Manta Ray is targeting three phases of development, culminating with a fully integrated demonstration vehicle completing an underwater mission in a dynamic, open-ocean environment.
DARPA has selected companies like Lockheed Martin Advanced Technology Laboratories, Northrop Grumman Systems Corporation, Navatek, LLC, and Metron, Inc., to work on the development of integrated solutions for Manta Ray technology. Specific areas of interest include energy management techniques, low-power means of underwater threat detection, and innovative mission management approaches.
In Sep 2021, Martin Defense Group was awarded a $54.8 million contract to develop control software and energy harvesting module for the Defense Advanced Research Projects Agency’s long-range unmanned underwater vessel. The effort is under the second developmental phase of DARPA’s Manta Ray UUV program and the Honolulu, Hawaii-based small business is expected to complete the software and module by August 2024, the Department of Defense said Wednesday. The aim is to develop an energy-harvesting system to power it indefinitely, allowing the robot sub to carry out missions lasting months or years without returning to base or refueling.
DARPA launches Phase Two of Manta Ray UUV maritime drone project in Dec 2021
In December 2021, DARPA entered Phase Two of the Manta Ray Unmanned Underwater Vehicle (UUV) maritime drone project, having initiated the project in 2020. DARPA signed agreements with defense companies Northrop Grumman Systems Corporation and Martin Defense Group to advance the project beyond conceptual and schematic stages. The focus of Phase Two involves the development of full-scale demonstration versions of the Manta Ray UUVs, with teams conducting subsystem testing, production, and submarine demonstrations. The project aims to showcase the operational capabilities of Manta Ray UUVs, designed for long-distance and endurance aquatic missions. Despite DARPA’s limited disclosure, a YouTube video titled “Manta Ray – Breaking the UUV mold” provides glimpses of its potential applications, such as data collection and surveillance, with the main UUV stabilizing itself to release a secondary drone for additional tasks before both return to the host UUV.
In Sep 2023, DARPA’s Manta Ray program hit a key milestone with an in-water splash test off of Oahu, Hawaii, of performer PacMar Technologies’ scaled prototype to verify sensors, vehicle hydrodynamic performance, and key autonomy behaviors of the glider body. Manta Ray aims to develop and demonstrate a new class of long-duration, long-range autonomous underwater vehicle. The program approach includes rapid prototyping and early risk reduction prior to culminating in a more complex, full-scale final demonstration at sea.
“Splashing a vehicle is a major milestone for an undersea program,” said Dr. Kyle Woerner, Manta Ray program manager at DARPA. “This test provides important insights into key systems, allows us to validate assumptions and models, and gives us valuable data in preparation for our upcoming full-scale at-sea demonstrations. We are a critical step closer to realizing the program’s objectives for a new class of long-endurance autonomous underwater vehicle.”
PacMar Technologies and Northrop Grumman are the two Phase 2 performers on the Manta Ray program. Northrop Grumman is targeting a test of its prototype in 2024.
Conclusion:
The DARPA Manta Ray project represents a significant leap forward in the field of underwater exploration and defense. As the US Navy pivots towards an integrated hybrid force, the development of large UUVs is proving to be a game-changer. The collaboration between industry leaders and the government underscores a commitment to innovation that not only enhances military capabilities but also sets the stage for advancements in underwater exploration, surveillance, and environmental monitoring.
By pushing the boundaries of UUV capabilities, DARPA is paving the way for persistent and versatile operations beneath the ocean’s surface. The Manta Ray’s potential to operate independently for extended durations heralds a new era of persistent and cost-effective underwater operations, making it a critical asset in the pursuit of maritime dominance.
Whether applied to military endeavors or scientific research, the Manta Ray’s large payload capacity, long endurance, and adaptability position it as a revolutionary tool in the ongoing quest to unlock the mysteries of the underwater world. As this project progresses, the potential for new discoveries and applications in underwater exploration is both exciting and promising.
References and resources also include
https://www.janes.com/article/88185/darpa-sets-out-goals-for-manta-ray-uuv-development
https://dronedj.com/2021/12/29/darpa-launches-phase-two-of-manta-ray-uuv-maritime-drone-project/