The DirectINJECT Project was initiated to develop a reliable in-line dosing system to deliver a concentrated silver ion biocide solution at ultra-low flow rates into spacecraft potable water. Three dosing systems, employing a miniature peristaltic pump, a multi-piston pump, and differential pressure-driven flow through a capillary tube, were quickly prototyped and tested. Although the peristaltic and multi-piston pump systems met the desired flow rate range, the capillary system showed the most promise and was chosen for further development. In FY23, the Capillary DirectINJECT dosing system underwent extensive testing with a nominal injection rate of 1.0 ?l/min into varying backpressure conditions. A Primary DirectINJECT System with triplicate testbeds was employed for long-term testing, and auxiliary systems including the Secondary DirectINJECT System and Leak Testbed were developed to characterize specific components and investigate various phenomena related to the dosing system. Parameters such as flow rates, reservoir pressures, and temperature were monitored throughout the testing campaigns.
Parodi et al. (Sun,) studied this question.