Uncrewed Systems Technology 048 | Kodiak Driver | 5G focus | Tiburon USV | Skypersonic Skycopter and Skyrover | CES 2023 | Limbach L 2400 DX and L 550 EFG | NXInnovation NX 100 Enviro | Solar power focus | Protegimus Protection

63 UUVs | Insight other designs in a test tank, as well as evaluating different picking processes, for their efficacy in nodule collection and their impact on sediments,” Gillham says. In the present design, the end effector puts nodules into a suction conveyor, which then pulls them into a hopper, to be unloaded after the AUV is recovered. A buoyancy engine enables the AUV to return to the surface while potentially carrying many kilos of nodules. Although not a new invention, Gillham and his team have developed a displacement buoyancy system geared towards manufacturing and operational costs per kilo lifted, as well as reliability and survivability at depths of several thousand metres. “A lot of smaller-displacement buoyancy engines are what I’d call ‘fixed- mass, variable volume’,” he says. “They always have the same mass, and change size using a piston or pump actuator, so they expand or contract to change the amount of water displaced. “We have a fixed volume though, using a pressure vessel designed to resist external pressures at extreme depths. By pumping lots of water in and out of that vessel, we can adjust our buoyancy dynamically, so as we harvest and add mass to the AUV, we also offset that mass by pumping water out of the vessel. “The potential energy of work needed to take those nodules from the seabed to the surface is actually equivalent to the work of pumping the water out from the buoyancy engines. So once we’re at capacity at the end of a run, we just pump a bit more water out and float up to the surface.” He adds that for horizontal propulsion and high-frequency vertical adjustments, the Eureka 1 has 12 electric thrusters, while the Eureka 2 will have eight, as well as several control surfaces. Impossible Metals plans to test this new iteration at far greater depths than its first prototype, potentially at 4000-6000mbelow sea level. This will include investigating ocean currents and how best to compensate for themduring transit relative to the seafloor, with live positionmonitoring enabled through integrated USBL systems. The company anticipates the first commercial uses of its system in 2026 at the earliest, as regulatory frameworks are put in place for responsible access to this mineral resource. Networked inspections As UUV missions and capabilities progress, our coastlines and oceans could see increasingly high levels of underwater traffic as uncrewed systems monitor, inspect and interact with subsea assets. Although autonomy and sensing solutions enable UUVs to coordinate themselves in their navigation and actions, as swarms or some other group definition, the ability to wirelessly monitor uncrewed underwater systems, communicate with them and potentially take remote control of themwithout needing a tether – as is now commonly done with UAVs, USVs and UGVs – remains a sought-after goal for many UUV companies. Such technology would go a long way to giving assurances of vehicle safety, as well as the ability to analyse subsea data in real time and respond with optimal efficiency. However, traditional wireless comms fail underwater because electromagnetic waves are rapidly attenuated. Acoustic comms pose an enticing alternative, but in reality they are around 200,000 times slower than EM waves. Optical modems meanwhile are a faster alternative but they lack range. “UUV operators using acoustic comms aren’t blind to how their UUVs are performing though, but the poor bandwidth and latency makes dynamic analysis and operations impossible,” explains Manu Ignatius, CEO at Subnero. “And in shallow waters they struggle to get even periodic telemetry updates from or commands to their craft owing to multi-path, Doppler and other noise- related effects.” Uncrewed Systems Technology | February/March 2023 Nauticus Robotics’ Aquanaut UUV uses acoustic modems from Subnero for enabling live telemetry and updates during underwater operations (Courtesy of Nauticus Robotics)