Theoretical and Experimental Research on Pirani Vacuum Sensors for In-situ Detection in Near-Space

In this paper, a micro-electromechanical system (MEMS) ultra-low pressure sensor is developed, which is specifically tailored for rocket sounding systems and provides an in-situ detection approach for pressure measurement in the near-space environment. To enhance the overload resistance of the sensor, a composite film consisting of aluminum (Al) film and photosensitive polyimide (PSPI) film is adopted. Meanwhile, its sensitivity is improved by optimizing the structural grooves. The structural parameters of the sensor are determined through theoretical analysis and simulation modeling, and its overload resistance capability is evaluated via ground tests. The test results demonstrate that the sensor has a measurement range of 5 - 6000 Pa, an accuracy higher than 7.73%, and an overload resistance exceeding 200g. Furthermore, actual rocket sounding flight tests confirm that the sensor can effectively withstand the overload impact during rocket launch and successfully detect the air pressure data in the near-space range below 72 km, thus verifying its feasibility as an in-situ pressure detection method for near-space.