AirVenture’s unofficial prize for the most popular aircraft at each year’s fly in – the brown grass award, named for the trampled turf around the much-thronged craft, had a CAFE Foundation equivalent at this year’s Electric Aircraft Symposium. That would be the crumpled carpet prize for the circles around Dr. Joseph (Joe) Armstrong, Chief Technical Officer for Ascent Solar, a Thornton, Colorado-based firm. Wearing a bandolier-like ribbon of extremely thin, flexible solar cells at the end of his talk, he was surrounded by break-takers eager to get a closer look at his impressive array of photovoltaics. Commercial production modules of the copper indium gallium (di)selenide (CIGS) cells have been verified at an industry-high10.5-percent efficiency by the National Renewable Energy Laboratory (NREL). The …