Figure 7

500 km LEO orbits that appear with more than 30° elevation from horizon and are visible between 0:00 and 6:00 am over La Palma for different inclinations. Comparison of the link duration between two 500 km low-earth orbits (LEOs): 97.3° sun-synchronous (red) and the optimal 30° circular orbit (blue). Only passes with more than 30° maximum elevation at night are shown. The average visible time per pass is 195 s (163 s) for CO (SSO), the total visible time per year amounts to 71,435 s (37,115 s) for CO (SSO).