Computer vision and stochastic approach for LEO objects attitude determination

A few objects larger than one-meter re-enter the Earth’s atmosphere every year. In total, about 75% of all the largest objects ever launched have already returned. Two current examples of large objects returned to the atmosphere are those of the Tiangong-1 Space Lab (April 2, 2018) and heavy-lift launch vehicle Long March 5B (May 9, 2021). The threat posed by space debris has become a global issue, and Space Situational Awareness (SSA) is a prerequisite for any space activity. Optical systems provide valuable assistance in identifying and monitoring such objects. The Space Systems and Space Surveillance Laboratory of University of Rome “La Sapienza” (S5Lab) carries out activities for space surveillance purposes and develop algorithms and software for analysing the data collected by optical systems. This article focuses on determining the attitude of space debris from their optical observation. For this purpose, a simulator of the space environment and a genetic algorithm were used through which it is possible to derive the presumed attitude parameters (Euler angles and angular velocities) that the object had at the time of acquisition.