In the rocket science "Oops!" department...

In all the excitement over the Curiosity rover on Mars, it appears that some of the scientists working on it decided to make sure that the rover did not have to load a drill bit. They attached one before launch.

What's the big deal, you say? A possible contamination with Earth microbes. The bit used had been sterilized, of course, but it was supposed to stay in its box and that would ensure that it would not pick up a stray microbe before the Curiosity landed on Mars.

Let me quote from an article in Newsday:

But that changed after engineers grew concerned that a rough landing could damage the rover and the drill mechanism. They decided to open the box and mount one bit in the drill as a hedge to ensure success of one of the most promising scientific tools aboard Curiosity. The drill is to bore into rocks looking for clues that life could have existed on the planet. Even if a damaged mechanism couldn’t load a drill bit, at least the rover would have one ready to go.

And they didn't tell the scientist in charge of the project.

I am not a scientist (and I don't even play one on TV) but it seems to me that the rover was in a "clean room" up until it was loaded on the rocket. And, even then, would have been protected against contamination during and after the loading.

I think the chances of actual contamination are pretty much worse than my chances of winning the Lotto.