You know about the shuttle already, so let's get to SDO, the Solar Dynamics Observatory. This payload's been awaiting launch forever. It's a unique mission, and one that's very interesting for those of us who live and breathe radio propagation.
Basically the SDO will ultimately reach geosynchronous orbit over New Mexico, from which it will return absolutely unprecedented data from observations of the sun at an absolutely mind boggling data rate. It will be able to fill a CD's worth every 36 seconds! This requires a dedicated ground station, with dishes pointed at SDO's stationary spot in the sky.
SDO scrubbed this morning after wind violated launch constraints. The Atlas booster's computers auto-aborted the count at T-3 minutes. The next opportunity is Thursday morning at 10:23 a.m. - 11:23 a.m. EST (1523-1623 UTC).
The SDO Launch Blog is here.
You can also follow SDO on twitter. Tweets are written in the first person, as if the payload is talking. They're fun and informative, and SDO has a huge following.
This mission's going to be good.