The problem is that the satellites are moving very fast and there are a lot of them. The mean free path may be very long, but if the satellite is moving very qu

The problem is that the satellites are moving very fast and there are a lot of them. The mean free path may be very long, but if the satellite is moving very quickly it will cover that distance fairly often. This means that they will have to actively avoid collisions fairly often. https://en.wikipedia.org/wiki/Cross_section_(physics) https://en.wikipedia.org/wiki/Cross_section_(physics)