Aerogel

[Zema Bus]

[Grogan]

I meant to get back to this and forgot and noticed while looking for another post in here.

It's a very strange substance, made using supercritical methods (temperature, controlled vacuum pressure to remove liquids and leave the solid molecules behind in the lattice).

I don't know how practical it would be for "dragging through a comet's tail to slow down particles for study" but it sure would have light weight insulation uses. Put it between two thin panes of plastic to make a thicker insulation barrier etc.