(I just realized how annoying an entry this long will look in people's Friends views, so most of this entry is cut. The summary won't make much sense unless you read the whole thing, though.)
When the Challenger blew up, I was in my first year of college. I was on my way to class in the courtyard my dorm was on, and a dorm neighbour ran up to me and told me. I was very saddened, but not really shocked or surprised. Going into space and coming back involves tremendous forces delicately balanced, hugely complex machinery, and extremely large quantities of high explosives. It's not safe. I think at that point we were starting to think it was - the networks weren't always carrying launches live any more, and with no spectacular failures in the shuttle program it was starting to fade into the background of the national consciousness as communication satellites and the Interstate highway system had. We were starting to think that low-Earth orbit was just another place to go to work (albeit a very prestigious place, like Hollywood or the Senate).
But it's not. It's very dangerous, and it's very expensive.
The investigation that followed the Challenger disaster certainly showed that corners were cut that shouldn't have been, and risks were taken, sometimes under political pressure, that shouldn't have been. I don't mean to say that we shouldn't demand as much safety as possible from our crewed space program (if we're going to have one), or that there we won't discover concrete, identifiable mistakes, perhaps made by particular people, that led to the Columbia disaster. But we have only ever in the history of the species sent a few hundred people into space. We're new at this, and it's a hard thing to do. Just as people die building skyscrapers, and just as more of them probably died building the first few than do now, if we keep doing this, sometimes people are going to die.
That doesn't make it okay, of course, and it doesn't mean we shouldn't do our best to find out what happened and correct it. But those seven courageous people climbed into that spacecraft because they wanted to do something they thought was worth risking death for. Maybe, for some of them, that was the science. Maybe it was national pride. Maybe it was planetary pride. Maybe it was a simple commitment to getting one's job done. Maybe it was just the sheer thrill and excitement of riding a giant explosion into space and spending a couple weeks someplace very very few humans have gone. But (whatever one's opinions about the wisdom or cost-effectiveness of the crewed space program) they did not die for nothing.
In a few weeks George Bush is probably going to send U.S. soldiers to kill and die in Iraq, and even if the war is shorter than the last war, a lot more people are going to die in Iraq than did on the Columbia. And surely very many of them will be civilians, who can't be said to have chosen the risk of death even to the limited extent an Iraqi draftee can. The death of seven astronauts was a tragedy. The deaths of soldiers and civilians in war will also be a tragedy, and in my opinion a much more senseless and unnecessary one.
What I experienced when the Challenger blew up was not so much shock and surprise as sadness and apprehension - apprehension that the space program would be shut down or diminished. It seems likely at this point that there will be at least an interruption in the Shuttle program, and perhaps an interruption in US/Russian human presence in space entirely (unless the US pumps enough money into the Russian Space Agency for them to build enough launch vehicles to keep the International Space Station staffed).
I admit I haven't been following the shuttle science results very closely (perhaps because there haven't been that many - most of the shuttle missions are military these days), but it seems like the spectacular science that has come out of NASA in the past few years has come from uncrewed probes and space telescopes. When a Mars probe blows up on launch or fails to enter orbit, it's a terrible lost opportunity, but it's not the kind of human tragedy that the death of a shuttle crew is. The risk is less, and although there's certainly some kind of intangible value to having human explorers in space, the concrete scientific rewards are greater. So as much as I like seeing humans in space, I don't feel that a couple years or so hiatus on crewed missions is a bad thing (particularly if some of the crewed missions that don't happen would have killed people!). And given that China is going to send somebody into space soon, and perhaps India will follow, I'm sure that my species (and my nation) are going to continue to shoot people at high speed off the planet with some regularity, for bad reasons as well as good. And maybe a medium-to-long hiatus in US crewed spaceflight would be a good thing even within the context of human spaceflight if it gave NASA the time to redesign the space shuttle and we end up sending people up in 2020 or so on a vehicle that's much safer and more efficient.
So an interruption in crewed spaceflight is not what I worry about right now. What I worry about in the present political climate is that spaceflight (perhaps all spaceflight) will be taken away from a nominally civilian agency (albeit a highly militarized one) and put under the direct control of the military. That scientists will have less access to space, and warriors will have more. That future US space launches will be handled the way they were in the Soviet Union - classified until they succeed, so that failures can be kept quieter. Sure, without shredding the Constitution considerably further than it's been shredded our Ministry of Truth can't keep launch or reentry failures a complete secret, but we can probably keep them lower-profile. (Compare war coverage of Vietnam with war coverage of the Gulf War. The Ministry of Truth learned its lesson.)
So I guess I worry that this tragedy, like the much greater tragedy of September 11, will be used as justification for making my country a little more secretive and a little less open. For giving the military-industrial complex and the spies and the appointed officials a little more power, and giving scientists, journalists, and elected officials a little less. If crewed spaceflight has a purpose, it is to celebrate the human spirit of adventure, curiosity, and exploration, of shared endeavour and individual courage. Secrecy, hierarchical control, and warmaking do not do that well, and I hope the space program is not overwhelmed by them.