On the main side, the front side of our ice cube tray, if you will, we exposed that when we flew past the comet, so we caught the comet dust.

NPR: Stardust Set to Deliver Comet Samples

The collector basically looks like a tennis racket filled with ice cubes, so this is kind of like a big ice-cube tray, and each ice cube is not made out of ice, but it's made out of this aerogel.

NPR: Stardust Set to Deliver Comet Samples