I'm watching the video feed from the top kill, and so far it's a little more interesting than watching paint dry. I think that what they are doing is assessing the various parts of the apparatus, but I'm not knowledgeable enough to know exactly what I'm looking at. I can identify probable functions of various parts, but I don't understand how the whole goes together.
Emptywheel (bmaz in particular) has an open thread going. So far it is dominated by someone who has no idea that the mud pipe will be attached to the well. His concern is that the mud is just going to go all over the place. There is also some confusion as to the difference between top kill and a junk shot.
If this were an action movie, Captain Obama would be sitting in his captain's chair with a big monitor of the action. "Pipe in place," he would order masterfully, and we would zoom in on the pipe moving into place. "Start mud flow." There would be some slight jerks of the equipment, the oil plume would, after a suitably suspenseful pause, slow down just perceptibly, then unambiguously, and the water would become a clear blue. Fishes and octopuses would begin to return.
And it wouldn't take longer than ten minutes. With suitable music.
What is this stuff of checking everything out anyway? Boooooring! Let's get to the main event.
Update: Here's some commentary on the video that makes more sense. Even the experts can't entirely tell what's happening. And some labeling of the video here.