Log entry time 08:54:44 on April 17, 2011

Entry number 228861

I have to head out of town for a week of parental maintenance. But my reading of our situation is we are facing 3 possibilities:

1. The turbopump is toast. This hypothesis is bolstered by the fact that the turbo controller fault light doesn't go off even when the stop button is pressed. The fault light should clear when "stop" is pressed. Dave Gaskell tried different controllers to no avail. Therefore there is something wrong with the pump itself. Note that the pump is in a relatively "quiet" area radiologically. No SS there. The half-lives are short and it is upstream of a big green shieldwall we have in place to shield ourselves from the hot stuff. I think it's quite likely that the pump could be replaced Monday. We may need a team to help the techs do this since they are already dosed out at some level. However I don't think the levels in this area will be that high by early next week. If the pump is the problem then we could have it replaced Monday, target cooled Tuesday, and be back on the air Tuesday night!
2. We have another leak. Then we'd be facing a long cooldown period on the order of 10 days before anything could be done about it, assuming that we'd even be allowed to do anything about it again. How dire this option is would depend on where the leak was. Perhaps tightening the bellows flange could be tried first, a relatively quick thing to do.
3. Both of the above.

Obviously I am rooting for option 1. It's our only quick path back, perhaps our only path this spring at all. I agree with Jay that it looked like a vacuum problem. However it did not look like before, like a month ago. It was way too quick. It might just be the pump got fried finally from the radiation. In any case that's the path we have to explore first.