What kind of garbage is in the photos from the stratosphere?

Question

Physics

I looked at the photos taken from the stratospheric balloon and found some debris. What could it be?
Circled in red squares:

Answer 1

Looks like dust/debris on or near the lens.

Answer 2

Just the same, I would have thought that this is not dust on or near the lens, based on the fact that the focus is at infinity, and these things are sharp enough, it would certainly not look like that.

Answer 3

These are fragments of a burst weather balloon.