The primary hygiene component of a standard shipboard ‘fresher is a cylindrical translucent compartment, resembling a drug capsule set on its end, with a watertight sealing door. At top and bottom, gratings conceal powerful counter-rotating fan/turbine units.
In dynamic mode, these fan/turbines are engaged to blow (at the nominal “top”) and suck (at the nominal “bottom”) a water/air colloid past and over the bather at configurable velocities ranging from strong breeze to hurricane-strength wind, providing the water with a functional simulation of gravitic flow – a “shower”. To conserve water where necessary, many ‘freshers recirculate filtered water while in operation, requiring fresh water input only for the initial fill and the final rinse cycle.
In static mode, the gratings close and the capsule itself fills entirely with water – a microgravity “bath”.
In the former mode, breathing while bathing is, at best, difficult; in the latter, it is downright impossible. Early-model ‘freshers included a built-in breathing mask connected to ship’s life support to ameliorate this problem; in these days of respiratory hemocules which enable the modal transsoph to hold their breath for over an hour, ‘fresher designers tend to assume that this will not be a problem. Those without such hemocules must, therefore, remember to take a portable breather with them when bathing.
– The Starship Handbook, 155th ed.