Design of high-resolution flow sensor used in cold gas micro propulsion system

Cold Gas Micro Propulsion (CGMP) is a reliable technology for spacecraft attitude and orbit control used in drag-free control system to compensate the environmental disturbance from the aerospace. The CGMP requiring a very fine control resolution and low noise is desired to be used on TAIJI mission for gravitational wave detection which is supported by Chinese Academy of Science (CAS). One of CGMP's key technologies is high-resolution Gas Mass Flow Sensor (GMFS). In this paper, calorimetric thermal flow sensor characterized with miniaturization, high sensitivity and low noise is studied by simulation method and manufacturing process. By simulating the influence of heating power, electrode distance, temperature, etc. on sensor response, the methods on optimizing sensitivity and accuracy have been proposed. The sensitivity is about 2.53 mV/(m/s)/mW. An amplifier circuit with ultra-low noise of 7.29 nV/Hz for reading out has been designed, which is essential for high resolution. The sensor was fabricated and preliminary tests have been conducted. The sensitivity of the sensor is about 100 mV/(m/s).