Pico-Satellite Solar Cell Experiment (PSSC)
I just head that Endeavor will eject a small picosatellite (5x5x10 inches) that will test two different types of solar cells in the environment of space before it begins its deorbit maneuvers. I was interested in seeing if I could find any downlink frequencies for it, but haven’t managed to do so. I did find the following NASA page: