Seems like everybody is trying Too hard to make something out of nothing. Unless this was a repeatable result where the same coordinates in the sky at the exact altitudes produce the exact repeatable pattern, this is the equivalent on random spill/splash from liquids onto a piece of paper that was then dried. There are plenty of stuff up there besides cosmic rays that will interact with film.

hmmmm i doubt thats cosmic rays, seams more like extreme temperature and low presure did something to the films chemistry

I would have expected static.

Space is, like, cool.

using a helium balloon

Your own source stated that it was hot air.