[El Gato]

If it is little pieces, as they hoped it would be, the pieces may drift a long way and take a long time to come down.

Actually smaller pieces will in general come down faster, because they are more affected by the slight drag of the upper atmosphere which is present even at the 200+ mile altitude where the dead bird started out.

[zot]

Actually smaller pieces will in general come down faster, because they are more affected by the slight drag of the upper atmosphere

No, smaller pieces come down slower because they are more affected by the drag of the atmosphere all the way down. Of course, it depends on the shape of each piece. For the same weight, a sphere falls fast: a thin piece flutters down slowly.