Nanotech scientists at the University of Glasgow are figuring out how to use smart dust to explore planets. Each piece of dust would be about a millimeter wide, and would have a processor, sensors, a generator and digital communications gear on board. It would be covered with a shape-shifting plastic sheath that would allow it to be steered, gliding with planetary winds and returning data to its mother ship.
Put together a swarm of thousands of these babies, teach them to communicate with one another, and you'll have a whole herd of sensors that can coordinate their movements, exploring planets, riding Martian winds and terrifying the neighbors. The scientists admit there are no censors small enough to fit into such grains of sand, and they're saying technology allowing this little trick might be coming along in the next few decades. How far-fetched is this, anyway?
This may not be that far from reality. A few years ago, Ray Kurzweil told us of smart dust swarms already being used for spying, so the idea of using them to explore other planets sounds like an even better idea. Maybe those techno-wizards could build puny little spaceships for the dust particles, much more efficient than today's cumbersome space probes.