I really enjoy watching the International Space Station fly over head. I subscribe to alerts so I know when it is in my area during the night time. I wouldn't be able to see it if it weren't for the light. Perhaps the light is only so we can see it more easily. I'm not exactly sure why there is a light on it and I've searched for answers.
Why is there a light on the International Space Station facing us on Earth?
It's a very bright white light. It's not a blinking light for collision avoidance. It uses power, maybe not a lot but still a consideration.