Aspen Aerogels, Inc.
A maker of ultra-lightweight aerogel insulation, the world's airiest solid material, Aspen Aerogels spins it into thin flexible blankets like Pyrogel and Cryogel that keep pipes, tanks, and industrial equipment at refineries and power plants from losing heat. The technology grew out of 1990s NASA work to manage cryogenic rocket fuel, and the company spun off from Aspen Systems in 2001, taking part of its parent's name and adding "Aerogels." Fun fact: its insulation is so light it was once called "frozen smoke."