Nanocardboard plates able to levitate when light is shone on them could explore other worlds.

Penn engineers with funding from the National Science Foundation, have nanocardboard plates able to levitate when bright light is shone on them. This fleet of tiny aircraft could someday explore the skies of other worlds, including Mars. The thinner atmosphere there would give the flyers a boost, ...This is an NSF Multimedia Gallery item.
Source: NSF Multimedia Gallery - Category: Science Source Type: video