Infrared sensor system using robotics technology for inter-planetary mission

摘要

Infrared sensor system is a major concern for inter-planetary missions in order to investigate the nature and the formation processes of planets and asteroids. Since it takes long time for the communication of inter-planetary probes, automatic and autonomous functions are essential for provisioning observation sequence including the setup procedures of peripheral equipment. Robotics technology which has been adopted on HAYABUSA2 asteroid probe provides functions for setting up onboard equipment, sensor signal calibration, and post signal processing. HAYABUSA2 was launched successfully in 2014 for the exploration of C class near-Earth asteroid 162173 (1999JU3). An optical navigation camera with telephoto lens (ONC-T), a thermal-infrared imager (TIR), and a near infrared spectrometer (NIRS3) have been developed for the observation of geology, thermo-physical properties, and organic or hydrated materials on the asteroid. ONC-T and TIR are used for those scientific purposes as well as assessment of landing site selection and safe descent operation onto the asteroid surface for sample acquisition. NIRS3 is used to characterize the mineralogy of the asteroid surface by observing the 3-micron band, where the particular diagnostic absorption features due to hydrated minerals appear. Modifications were required in order to apply robotics technology for the probe due to the difference of operation on satellites from robot operation environment. The major difference is time line consideration, because the standardized robotics operation software development system is based on event driven framework. The consistency between the framework of time line and event driven scheme was established for the automatic and autonomous operation for HAYABUSA2.