Issue 54 Uncrewed Sytems Technology Feb/Mar 2024 uWare uOne UUV l Radio and telemetry l Rheinmetall Canada medevacs l UUVs insight DelltaHawk engine l IMU focus l Skygauge in operation l CES 2024 report l Blueflite l Hypersonic flight

60 Insight | UUVs operations. Such is its usage that the US Navy has initiated a project centred around researching how hydrogen fuel cells might be leveraged to recharge AUVs without needing them to return to an onshore base or mothership. Announced by the US Department of Defense and initiated via the US Naval Facilities Engineering Systems Command (NAVFAC) in response to the increasing use of UUVs around the world, the navy project uses a version of the Saab Sabertooth provided by Michiganbased subsea services company Hibbard Inshore as one part of the testing platform, the other part being the Subsea Supercharger (SSC) from Teledyne Energy Systems. Readers may remember that at the heart of the SSC is Teledyne’s ejectordriven reactant (EDR) fuel cell, which we unpacked in detail in our 35th issue (December 2020/January 2021). That proton-exchange membrane (PEM) fuel cell operates using a passive ejector-based system for circulating reactant gases, and hence has fewer potential points of failure than most valve-based fuel cells – a key requirement for entrusting it to function underwater for months at a time without needing a technician or crewed surface vessel to repair it. This tech gives the SSC a service life of at least 10,000 hours and a 1000 m depth rating. The system can output up to 5 kW of continuous power at up to 700 V DC, and through its hydrogen gas tanks it can be equipped with up to 30 MWh of energy before deployment (with H2 having several hundred times more specific energy than Li-ion batteries). The battery electric Saab Sabertooth in the project can operate for 12 hours (or travel for approximately 20 km at a depth of 1200 m) between battery replenishments. It recharges by docking with the SSC, which then uses its fuel cells to generate current from its H2 gas stores. Testing for the project will continue in early 2024, by NAVFAC’s Expeditionary Warfare Center. Offshore energy Resident applications of AUVs are highly tapped as a future mode of operations for the long-term security and maintenance of renewable and hydrocarbon energy infrastructures. As global demand for energy rises, UUV services and shipments are becoming more common across the oceans. Texas-headquartered multinational Ocean Infinity has signed a survey contract with Equinor Wind US, relating to one of the first-ever floating offshore wind farms to be located on the US West Coast. Ocean Infinity is to fully investigate and survey the site of the future wind farm (which encompasses 80.062 acres and potentially 2 GW of wind-power output under the contract) using multiple AUVs simultaneously, starting in February. Data from the survey will be gathered using AUVs from Ocean Infinity’s fleet, and it will be used to inform Equinor’s site assessment, design, construction and operations planning. The fleet includes multiple UUVs from Saab, as well as Hugin 3000 and 6000 AUVs from Kongsberg Discovery. The two Hugin AUVs are named for their maximum depth rating in metres. The 3000 measures 5.5 m long and 1 m in diameter, and weighs 1400 kg in air. It integrates 45 kWh of onboard energy, generated via an aluminium, oxygen semi-fuel cell and a battery powertrain that enables a top speed of up to 4 knots from its thruster. The Hugin 6000 weighs 1980 kg in air, and measures 6.18 m long and 0.875 m in diameter. It can achieve a maximum speed of up to 5 knots, with a possible endurance of 60 hours on its battery energy stores if working at an operating speed of 3 knots. Both AUVs come with modular payload bays, designed for equipping multibeam echosounders, side-scan sonars, subbottom profilers, CTD (conductivity, temperature and depth) sensors and other survey tools. Southeast in the Atlantic, Nauticus Robotics has been awarded a contract by Petrobras to deploy its Aquanaut UUV, detailed in issue 52 (October/November 2023), to support the Brazilian energy giant’s offshore activities, and increasing use of robotics and AI. The 4.2 t UUV is to be operated under supervised autonomy in Petrobras’ Deepwater Production Field, February/March 2024 | Uncrewed Systems Technology Nauticus Robotics has been given a contract by Petrobras to support its offshore activities using the Aquanaut UUV (Image courtesy of Nauticus)