According to the method and device for a membrane-based processing of ambient water-group species, the species are captured in a space environment by an ionic liquid disposed on a presenting face of a semipermeable membrane. To seamlessly process the captured species for in-situ resource utilization without need of moving parts, they are urged to pass through the membrane by a predetermined electric potential difference applied between opposite sides of the membrane via electrode contacts; an initial storage envelope is provided by an impermeable membrane attached to a back face of the semipermeable membrane. The device can be stowed in a manner of rolled plastic and deployed by unrolling. The device can also be configured as a scientific instrument to monitor a flux of ambient water-group species impinging in the space environment using electrical measurements.