What did I beak now?

I checked my bike over before the raccoon ride and found the source of the rattling. It seems my rear cassette had come loose. This is where the rattling was coming from. I decided to take it off to clean it and had a bit of difficulty getting the third gear off. I found the following when I got it off:

I put it back on and tightened it up and assumed it would be OK. Well, at the end of the ride at Raccoon it stated rattling again. Apparently it is going to keep coming loose, so I called up Cahaba and asked them to order me a new hub outer shell. I may need to get a new cassette also just to be on the safe side.

Since the BUMP n Grind race is this weeked, I am probably not going to get much riding in. I am going to try and make a short road ride tomorow morning (since i have plans for most of the day Satuday and Sunday is pretty much out also) so I can at least get a few miles in this weekend.