Why are the satellites in the initial train visible to an observer on the ground experiencing night?

Answer

Their large, flat solar panels catch the sunlight while the satellites are in LEO.

Visibility occurs during 'sunlit passes' when the observer is in darkness, but the satellites are still high enough above the horizon to be illuminated by the sun.

Why are the satellites in the initial train visible to an observer on the ground experiencing night?

#Videos

Explaining the straight line of lights in the night sky - YouTube

astronomymovingstarsskysatellitessightingsmoving lights