When the Space Shuttle Endeavour lifts off later today, it will be carrying three satellites. But they won't be filling up the cargo bay, because all three would fit easily in one crew member's shirt pocket.
The thumbnail sized satellites are named Sprite, and were developed by scientists at Cornell University to see just how small a functioning satellite can be. On this trip, they will be attached to the outside surface of the International Space Station, so the Cornell team can see how well they hold up in space over a few years. They also want to see how easy it will be to pick up their tiny radio signals.
If all goes well, the team plans to make large numbers of the little buggers. Then they will launch them in a huge swarm that will ride on solar winds towards distant planets.
I'm just trying to comprehend how they plan to pick up such a tiny signal from what could eventually be millions of miles away. I have a hard enough time picking up WFMU from 20 miles away in New Jersey.