Uncrewed Systems Technology 047 l Aergility ATLIS l AI focus l Clevon 1 UGV l Geospatial insight l Intergeo 2022 report l AUSA 2022 report I Infinity fuel cell l BeeX A.IKANBILIS l Propellers focus I Phoenix Wings Orca

80 Dossier | Infinity APWR fuel cell to 2008,” Smith recounts. “Right away we put together short fuel cell stacks made of the same kinds of COTS MEA [membrane electrode assembly] and graphite hardware for part of the build, but for most of that period we were really concentrating on the water removal part of our IP, which NASA was happy for us to do.” Around 2007-8, NASA began looking into the prospect of returning to the Moon (an ambition now being realised through its Artemis programme). So, in 2008 Infinity started receiving funding from NASA’s Constellation programme, a forerunner of Artemis with the added goal of completing the ISS, to accelerate its fuel cell r&d for the Altair lunar lander in a Phase Three of the SBIR. “That allowed us to implement a new design – a metallic, diffusion-bonded, monolithic BPP which contained the hydrogen and oxygen flow fields, coolant flow fields, product water flow fields and the phase separation membrane itself for separating the fuel cell product water from the oxygen gas, all in a very thin pore chamber assembly,” Smith explains. “Initially we developed this for the NASA programme in 50 cm 2 active area sizes, and then produced our BPPs and MEAs in 150 cm 2 sizes, potentially for use in much larger and hence more powerful and power-dense fuel cells. NASA were happy with the performance of those cells and subsequently funded a range of short and tall cell stacks for testing.” Such was NASA’s enthusiasm that it put Infinity in touch with the US Navy, who had a similar (albeit maritime) interest in air- independent power systems. That gradually led to research and solution development for the navy, such as that already being carried out for NASA but funded through the Office of Naval Research. Beginning in 2012, it continues to this day and is aimed at naval UUV applications. “That continued development across different users enabled evolutionary changes to our engineering approach, allowing us to achieve higher differential pressures between the oxygen and by- product water,” Smith says. Most recently, fresh efforts by NASA to land on the Moon, and the growing private space industry, have brought another wave of funding to increase Infinity’s focus on orbital and lunar missions. This has included the flight of a NASA-funded, fully integrated Infinity PEMFC system, designated the Advanced Modular Power and Energy System, aboard the recent Blue Origin New Shepard-23 rocket flight. That mission was curtailed owing to an anomaly, but the fuel cell functioned successfully and produced valuable data. “Now, with the stack’s technologies having been developed, matured and proven in a variety of test cases, we’re at a place where product deployment makes the most sense to us,” Smith comments. Regenerative fuel cell As mentioned, Infinity produces individual cells with active areas of 50 and 150 cm 2 , with Smith noting that his team also makes 300 cm 2 cells, and can produce others. The cells are circular in shape, unlike the rectangular form taken by most PEMFCs we have previously covered, with a radius of just under 4 cm in the 50 cm 2 cells, just under 7 cm for the 150 cm 2 cells, and roughly 9 cm for the 300 cm 2 cells. Naturally, the highly customised nature of Infinity’s solutions for space and subsea users makes it challenging to give exact figures on all the permutations of its PEMFCs, and certain aspects such as mounting points have not yet been standardised. However, Smith showed us a test unit that is the most likely to be productionised first. December/January 2023 | Uncrewed Systems Technology Infinity has developed larger stacks, such as this 3 kW PEMFC system, shown here on a transport frame Now that the stack’s technologies have been developed and proven, we’re at a place where deploying products makes the most sense to us