The horses appeared to be interested and always come close to watch.
Have to look into these coatings.I think the best thing to do is run a test using actual balloons and a garden hose.My only concern would be reaction to balloon film using any product.A real time test would do the trick then look over the materials over time.Maybe even put high pressure into to them to see if they still have the strength to hold gas.
Even with water repellent balloons,the payloads themselves would need to be able to NOT act as a sponge of hold water on the surfaces.
Moisture on the brittle solar cells then freezing could create cracks...end of flight in itself.
If not for solar cells needing to be flat,a ball shape container would be best rather than rectangular.I see these styro balls in local craft supply stores but mounting solar cells may be tricky.Maybe they would need to be mounted like a satellite.
This is what makes the hobby fun,trying new ideas.
