What a week!

The tenth planet of the solar system has been discovered, with the provisional name 2003 UB313 and a more elegant name to be unveiled at some point. It's been 75 years since the solar system added a planet to the family, and this may well not be the last. And no, I don't believe for a second that Pluto will ever be demoted -- it's a planet, with far more reasonable arguments for its status than, say, Europe's as a continent, and ever more shall be so. Brian Marsden tried that trial balloon of demoting Pluto a few years ago, and the backlash was clear. Once a planet, always a planet, I think is the way it's going to be, and I'm entirely comfortable with that.
One proposal that makes sense to me is that we set an arbitrary cutoff at 1,000 km radius. Nice round number. Pluto and the new planet qualify, nothing else yet discovered does. If we find more of these big objects, so be it, then the solar system grows.
And that's not the only big new object of the week. Another newfound Kuiper Belt Object, also bigger than any other found before, but less than Pluto, and this one has a moon as well, allowing its mass to be nailed: 1/4 Pluto's.
And there's a lovely new lake on Mars, from Mars Express, frozen (all the way down??) in the bottom of a crater, but shining blue and looking ready to dive into. The first naked ice on Mars, at least outside the polar caps.
And Enceladus, Saturn's tiny moon that Cassini just swept by twice as close as the space station's orbit above Earth. An extraordinarily active world, for its tiny size, emanating gases through tectonic cracks.
Wow. And all this as the shuttle's dramatic roller coaster unfolds, already quadrupling the Internet record set by NASA's website just three weeks ago with the Deep Impact mission. Quite a week in space news.

Last flight of the shuttle?

This is a sad day for NASA. After what had looked like a perfect launch on Tuesday, inspection of the launch pictures on Wednesday showed a falling chunk of foam almost as big as the one that doomed Columbia. No, this one didn't hit, so the crew is presumably safe, despite a couple of what appear to be the commonplace (though not necessarily safe!) kind of dings on thermal protection tiles. But the fleet is once again indefinitely grounded until they figure it out.
Think about it: They just spent 2 1/2 years working specifically to solve this exact problem. They failed. How long will it take next time? Is it possible?
And if this ends up taking a long time once again -- and frankly, it's hard to imagine why it wouldn't -- we may have just seen the last launch of a shuttle.
The fleet is supposed to retire anyway in five years. If half that is eaten up with further redesign work, would it even make sense to continue? Would it still be able to carry out enough missions to justify its continuation? Or, I suppose more likely, would they retreat from the 2010 retirement date?
I'm sure no such decisions will be made for a long time, but NASA is in for perhaps its toughest year yet. And it has had some very tough years.