The surface of Earth has 5E8 km². They have 1E4 satellites. They are in orbit for a few years, but let's assume all fall down. So you get one satellite per 5E4 km².<p>There are less than 1E10 humans. 1m² is too big for most humans, perhaps a human and an umbrella. So the surface of humans is less than 1E10 m² = 1E4 km².<p>With some mild assumptions, I get less that a 20% chance of a satellite hitting a human, assuming all fall down, they can't be aimed at the sea, humans are big, they don't disintegrate in air, and the hit kills the human. How do they get 61%?