Ready... any time now... ready... wait... errrrr!
Yesterday's launch schedule was delayed because of weather. Well, that's to be expected occasionally at the Florida space center. Florida gets a tremendous amount of rain, and it's important for the visual trackers and telescopes to be able to see the shuttle during the ascent phase. So if there are too many clouds, you have to wait a bit.
Word just came through... moments ago the decision was made to CANCEL today's launch attempt. Not a weather problem this time. Today's problem seems to be a malfunction in the tanking progress, as hydrogen fuel was pumped into the External Tank (ET). The leak appears to be at the joining plate between the ET and the pipe that carries away excess hydrogen gas. The danger is that a spark could ignite the gaseous hydrogen too close to the ET. Excess gas vapor is carried away by pipe to a safe zone where the excess is burned off.
Well... can't have any gas explosions there now, can we? Still, we're waiting for the momentous blast off for what will be Discovery's last trip to space.