DKos has just run several mournful diaries , each with many mournful comments, concerning the demise of the space shuttle program. A central theme has been that we used to be able to do great things, but now we can't do shit, two men today can't lift the spear of one of the heroes from that age,... I'd be the the last to deny the possibility that our society could be in decline, but the end of this boondoggle is hardly the most alarming sign of it. So here's the start of an argument that may make the I/P conflicts look like brotherly love in comparison.
Manned spaceflight is extremely expensive. What exactly has it bought us?
In the diaries and comments, lots of people remember watching the spaceflights on TV at some nostalgia-provoking moment in their lives. Fine, but such moments can be provided by a World Series, a family outing to a park, etc. Nostalgia can find a way without massive public funding. I'm asking something different- what unique public good was provided by this program?
There are four general answers which I've heard floating around:
1. scientific knowledge
2. a source of technical spin-offs
3. a step toward mankind's escape from a doomed planet
4. a science-flavored adventure story, inspiring us toward (1) - (3).
(1) Among most scientists, at least the ones I routinely talk to, the idea of manned spaceflight as a major contribution toward knowledge is not taken seriously. I can't think of a single contribution of the manned program to important knowledge, other than as an ultra-expensive way to put Hubble in orbit and fix it, rather than just sending up a cheaper fleet of Hubble's by unmanned rocket. Seriously, not one significant piece of knowledge required the manned program. Meanwhile, not to mention the much larger contributions of all sorts of earth-bound science, here's a bit of what the unmanned space program alone has turned up, just off the top of my head:
a) Experiments showing that the breakdown of the entire local-realist picture of the universe extends over kilometer scales.
b) Data on upper-atmosphere temperatures, crucial to models of global climate.
c) compelling evidence that about 6/7 of the matter in the universe is something altogether different from the stuff we are made of and know about.
d) compelling evidence that the expansion of the universe is actually accelerating, indicating that either ~70% of the universe's energy is in some vacuum background, or else something peculiar is happening.
e) confirmation that the clumpy universe we now see is the natural descendant of the hot dense nearly smooth universe back when it was all near the temperature of the surface of the sun.
What about the next stage? Unmanned satellites currently in orbit are likely to provide evidence soon to settle this question: did the universe flatten out in an enormous inflationary episode or did it flatten out in a previous cosmic cycle? Perhaps the biggest question we want to settle in space is whether there is some unrelated line of life and, if so, what's it like? Absolutely the last thing you would ever send up to find that out is something that can't be completely clean and sterile.
And so on. It's no contest. For science, we need unmanned flight. Manned flight is a costly negative.
(2) What about spin-offs? Here it helps to have some common sense about what type of work produces the highest payoff rate. In daily life do we need devices to sustain our life very safely in a vacuum without any access to food supplies? Or are there countless applications for very smart, low-power, increasingly autonomous automations? Now there have been some suggestions of real payoffs, like when my astrophysicist father-in-law said at a press conference that maybe his share of the moonrocks would cure his baldness, but somehow they never panned out.
Argument by authority is not the highest form, but I can't resist mentioning that the person most passionate in saying that the Apollo program and all the rest of the manned program was a horrible waste was none other than my late colleague John Bardeen. As the co-inventor of the transistor and the co-discoverer of the theory of superconductivity, he was deeply familiar with practical applications and how they actually come about.
(3) This is in a way the most pernicious of the arguments. The thought that there's some magic technical fix to escape the effects of our expanding populations and resource use is simply science fiction. The Earth's population increases at somewhere around 300,000 per day (off the top of my head). They're all heading to space? Such fantasies get in the way of serious action.
(4) OK, as a tv show it wasn't bad. We should, however, be able to get much cooler tv shows with fancy robotic cameras, much cheaper. If somebody really wants to see people awkwardly stomping around in a desert, I suggest it could be filmed in Arizona.