Design and Experimental Validation of a High-Precision Pressure Regulation Unit for Cold-Gas Micro-Propulsion

The next generation of space-based gravitational wave observatories, such as LISA, TianQin, and Taiji, requires ultra-precise drag-free control and therefore micro-propulsion systems with thrust noise below (Formula presented.). This paper presents the design and experimental validation of a high-precision pressure regulation unit (PRU) for cold-gas micro-propulsion, guided by a requirement-driven analysis of pressure-induced thrust-noise sensitivity. A first-order mapping translates the mission-level thrust-noise constraint into a subsystem-level pressure-stability target, yielding an upper bound of about (Formula presented.) and an adopted design budget of about (Formula presented.). On this basis, a dual-stage architecture integrating solenoid pre-conditioning and piezoelectric fine regulation is developed. Stochastic simulations indicate that thermal drift dominates at very low frequency, whereas pressure fluctuation is the dominant contributor in the main (Formula presented.) – (Formula presented.) control band under the adopted budget. Experimental validation under three operating modes shows that solenoid-only regulation provides the smallest performance margin, that the piezoelectric stage significantly improves outlet stability, and that the integrated dual-stage configuration achieves the strongest pressure-noise suppression in the mission-relevant sensitive band. These results provide a subsystem-level pressure-conditioning basis for the further development of high-precision cold-gas micro-propulsion systems for future drag-free missions.