In response to my NRO piece the other day, in which I wrote:

There are some space missions that will just never be jobs for robots. Building an orbital infrastructure that can both mine useful asteroids and comets, and deflect errant ones about to wipe out civilization, is unlikely to be done with robots. Building orbital laboratories in which biochemical and nanotechnological research can be carried out safely is unlikely to be practically done with robots. A new leisure industry, with resorts in orbit or on the moon, would be pointless, and find few customers, if we weren’t sending up people. Establishing off- world settlements to get at least some of humanity’s eggs out of the current single fragile physical and political basket is not exactly a job for a robot.

Kevin Drum replies, (inexplicably) incredulously:

That’s it? Mining the asteroids? The long-promised pharmaceutical revolution in zero-g? Sex in space?

Well, no, that’s not “it.” Those are just examples. And I don’t know where he got the pharmaceutical revolution in zero-g, or the sex in space. My point about the labs had nothing to do with zero-g. It was that there’s some research that might be too dangerous to perform on earth, and that vacuum makes a dandy firewall.

But the worst part is the final sentence, which I’ve seen repeated over and over: we need to colonize Mars (or whatever) so that humanity will live on in case we blow ourselves to smithereens here on Earth.

There’s really no polite way to put this, but the notion is simply nonsensical. Do space enthusiasts keep writing this stuff because their neurons stop firing before they put finger to keyboard, or is it just that they’ve been saying it for so long that it’s become a habit? Do they have any idea how dumb the proposition really is?

No, Kevin, we really don’t. One of the reasons we don’t is that you don’t even bother to put up any reasons to support your statement that it’s dumb, or nonsensical. You seem to think that it’s so obvious that it requires no explanation, and you think that simply calling it that makes it so. When you’re prepared to actually discuss it intelligently, then perhaps I’ll find your fulminating a little more persuasive.