Aspen, I think, tried to sell it to me for marine exhaust insulation a couple of years ago. The small sample I got demonstrated that it's flexible enough to conform to compound curved surfaces, and that it drops a fair amount of very fine ceramic dust when you handle it.
The dust made it a non-starter for me; engines don't like dust, and there's no way to encapsulate the aerogel that will reliably withstand exhaust heat.
The other non-starter; they never came back with a price for a sheet of the stuff; they just kept dancing around the issue. Too bad for them; yacht owners will pay big bucks for high tech.
Mike Halloran
Pembroke Pines, FL, USA