| MadSci Network: Astronomy |
Chris,
As far as I know no satellite has ever been used to deliberately attempt to contact extra-terrestrials. Any signals we send out from satellites would be just "leakage", that is, stray radiation from satellites that is actually supposed to go to other satellites or the Earth. We did send a deliberate message in the direction of the globular cluster M13 in 1974, using the Arecibo radio telescope. And several spacecraft, like Pioneer 10 and 11, did carry information about humans and the Earth in case extra-terrestrials found them. But these craft are going very slowly in astronomical terms and it will be a very long time before they even travel the distance to the nearest star!
As for information on SETI, you can't do much better than the SETI Institute's web page. There is also the SETI League, "the international grassroots organization dedicated to privatizing the electromagnetic search for extraterrestrial intelligence". You can probably find lots more information by just doing a web search.
Pauline
Try the links in the MadSci Library for more information on Astronomy.