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Experimental Validation of an Onboard Transient Luminous Events Observation System for VisionCube via Ground Simulation Environment

The VisionCube is a 2-unit CubeSat developed in house, of which the primary mission is detecting the occurrence of transient luminous events (TLEs) in the upper atmosphere and obtaining corresponding images from a low Earth orbit. An onboard TLE observation system of the VisionCube CubeSat is designed and developed by incorporating a photon-sensitive multi-anode photon-multiplier tube (MaPMT) and an image sensor. Also, a distinctive TLE observation software which enables detection of the TLEs and capture of images in a timely manner is devised. By taking into account the limited resources of a small CubeSat in size and power, the onboard observation system is developed employing a system-on-chip device by which both hardware and software can be integrated seamlessly. The purpose of this study is to investigate the functionality of the hardware and the validity of the software algorithm to show that the onboard system will function properly with no human intervention during the operations in space. To this end, a ground simulation facility is constructed to emulate TLEs occurring in space using a set of ultraviolet light-emitting diodes (UV LEDs) inside a darkbox. Based on the analysis of the spectral and temporal properties of the TLEs, the randomly generated UV LED pulses are chosen for verification scenarios for the TLE observation system. The validation results show that the hardware and the software algorithm of the onboard observation systems can effectively detect the TLEs and obtain the images during the in-orbit operation.