what are those small blobs, balls made of? Greenstuff or some creative art shop accessories?
They come from the filter element of a Britta water filter. The filter media are the little green balls and charcoal pieces mixed together.
To separate them I put some of the mixture into an edged baking sheet, lifted one end and started tapping the sheet. The balls are round and roll down the inclined sheet, while the charcoal pieces more or less stay put. Its a slow process but does result in a large number of balls in random sizes for the ships
Fluff for the balls on the ships is that they are plague spore carriers, dormant while at absolute zero in space. When the ships approach a planet, they dip into the upper atmosphere, warming the armored spores, which then release for re-entry into the lower atmosphere. When the spores cross a pressure gradient (say 3/4 of one atmosphere) they burst to release the plague spores which then spread on the winds.