Name That Space Debris!

So, who wants to guess what the unknown piece of debris floating around near the Space Shuttle Atlantis is?

I do! I do!

I'm going to guess that it's a....

Hmm...

I know. It's a wrench. That's my guess. I'll even go so far as to say it's a wrench made out of ice, thereby incorporating both of the ideas from the experts into one meta-explanation.

My other guess is that it's a hamster from a science experiment that went up in the payload bay. It got out, wandered into the cold, deadly vacuum of space and is now orbiting just outside the shuttle, a frozen chunk of lethal hamster meat intent on destroying the space station. Yup. That's probably more plausible.