Aerogel as ET Insulator

Has it ever been suggested to replace to the foam on the ET with an
aerogel insulator? Material science is far from being one of my areas
of expertise, but it would seem that an aerogel insulator would be a
win-win proposition:

1) The extremely low mass of an aerogel allows for a change in
insulating material without a payload lift penalty

2) Being a low density material, an aerogel would minimize the chance
of impact damage to the Orbiter

3) Aerogels have extremely low thermal conductivity, even lower than
polyeurethane foam insulation

4) Aerogels are known to be highly resilient in high-vibration
environments


There is a company called Aspen Aerogels that commercially manufactures
aerogel insulation products by the sheet. Perhaps their technology can
be be modified to suit the needs of the shuttle program.

Any takers?

-Craig