Design and characterization of MASI On-Orbit Servicing gripper trigger system based on pose measurement logic

This paper presents the development and testing of a contactless pose measurement system for space docking and berthing operations. The system is part of the Modular Androgynous Standard Interface (MASI) and is compatible with the Mechanical Interface for Capture at End-of-Life (MICE). The goal is to create a device that provides ultra-close proximity pose estimations to automatically trigger the MASI capture mechanism during the On-Orbit Servicing (OOS) capturing phase. The system uses nine infrared (IR) reflective proximity sensors to measure five degrees of freedom: three distances and two angles. One main advantage is that the target interface does not require sensors or markers. Moreover, by providing continuous measurements at 50 Hz, it enables real-time adjustments of the relative pose between the servicer and the target, reducing potential failures during docking or berthing operations. A mathematical model describing the relative pose between the sensorized and target interfaces was identified and validated through calibration. The testing was carried out on a hexapod platform to simulate different positions and orientations. The results show a strong and accurate performance throughout the measurement range. The system has reached Technology Readiness Level (TRL) 4. Future work will aim to improve the performance of the system and make the test environment more realistic to increase the TRL.