This is very similar to an idea I've had about terrestrial weather protection. I wanted to use square ETFE pillows filled with hydrogen and tethered down to mak

This is very similar to an idea I've had about terrestrial weather protection. I wanted to use square ETFE pillows filled with hydrogen and tethered down to make a flat roof over an area. Flamability is a concern, so testing is required. I think it will be fine if I fully surround each hydrogen filled pillow with nitrogen filled ones.