Determination of Space Object Size in LEO using Measurement of Brightness

The growing number of satellites and space debris in Earth's orbit is a significant concern for space traffic. Therefore, numerous observation systems on the ground and in space constantly track space objects. Considering that the fragmentation of space debris over time poses a risk to orbit, the size of objects should be determined to assess their potential impact. In this study, we observed one of the known satellites, SJ-6F, using passive ground-based optical systems in different locations. After that, the conjugate sphere radius of SJ-6F was estimated from the apparent brightness data, which was extracted from optical observations. Finally, it was compared with its actual dimensions. The results clearly showed the effectiveness of the proposed solution since the estimated (0.356 meters) and known radius (0.327 meters) of the satellite were very close to each other.