They’ve found a cause, and solution to the foam-falling problem that gouged the tiles on the last flight. I wasn’t sure they’d be able to do it at all, let alone this quickly. On the other hand, I think they could have continued to fly with it as is, and if they hadn’t found a solution, they should have. If it occurred again, it would only be a real problem on the Hubble mission.

I in fact think that the Shuttle is now about as safe as it can be made, and it’s in fact pretty safe. I’ll be very surprised if they lose another orbiter before they retire it. But even if I’m right, that’s no reason to not retire it (though many will attempt to keep it alive). I’ve never thought it should be retired for safety reasons (at least not because it kills astronauts occasionally). We lose people mining, in construction, driving, and even in recreation. The notion that we can’t afford to do so in space is silly. And in fact it’s ridiculous, when we’re losing people fighting a war, to argue that we can’t afford to do so to open a frontier. If we, as a nation, can’t grow up about this, and think that it’s not worth losing people occasionally. we should just give up.

As I’ve noted previously, and recently, the real problem with an unreliable Shuttle is that we can’t spare the vehicles. A reusable vehicle that’s not reliable isn’t affordable (one of the reasons that talking about “human rating” one is oxymoronic, and misses the point). And the real problem with Shuttle isn’t that it’s unsafe, but that it costs too much, for too little. There are a lot more useful things that we could be doing in space for that billion dollars per flight. Unfortunately, NASA is replacing it with a system that will be no improvement at all in that regard.