*Aerogel* is a strong, silca-based solid with a sponge like structure. It is 99.8 per cent air and is 1000 times less dense than glass.
Its insulating properties mean it can perserve delicate objects.
Test @ JPL show aerogel protecting a flower from direct flame!!!!!!
So when the particle hits the aerogel it buries itself in the material.
Thought id share its pretty freakin cool if you ask me ;)
http://www.jpl.nasa.gov/news/features.cfm?feature=490