Satellite Collision and Wall-E repost

Since this could be current events, I am reposting my analysis of space debris in the movie Wall-E.

Here is a shot from the scene where the space craft is leaving Earth:

In this scene, the spacecraft has to break through all the Earth-based space debris. The first problem is that the unused satellites are just sitting there. If they were to stay in orbit, they must move. Maybe the WALL-E creators are sticking with the no air means no gravity idea. At least they are consistent.

The other problem with that scene is the sheer amount of junk in orbit. Suppose that was 300 km above the surface of the Earth (the orbital distance of the space shuttle). What is the volume of of this space (say it is 100 meters thick - which is tiny). The volume of this shell would be:

Where r₁ is the radius of the Earth plus 300 km = 6.678 x 10⁶ meters and r₂ is 100 meters more. This gives a volume of 5.6 x 10¹⁶ m³. See - that is a lot of space. How many pieces of junk could fit in this? Let me give an overly large estimate that each piece of junk gets (on average) a cube of 100 m x 100 m x 100 m (1 x 10⁶ m³). How many pieces of junk would there be? Well, I can just take the amount of space available divided by the space for each piece of junk and I get: 5.6 x 10¹⁰ pieces. If Earth launched one spacecraft a day, that would take 153 THOUSAND years. Just saying.