What ever happened to Momentous? Water fueled thrusters were their thing. Well, space tugs and an attempt to pivot to satellite buses were supposed to be their thing, and water thrusters were supposed to be a differentiator for some reason. Somehow they haven't been delisted.
I do still think this technology could be helpful as we push out into deep space for mining, research, and habitation and can start to use ISRU to refuel. It's just a matter of when that will happen.