tom thinks

date 2000-11-23:18:20
Physics In "The Hymn of Breaking Strain" Rudyard Kipling laments the lack of standardization amongst humans, so we never know how well-made we are until we collapse under the load.

In fact, more complex things like aircraft and spacecraft were--in the days before big fast computers allowed us to perform virtual experiments--tested to destruction as part of the design process.

The Apollo command module, for instace--the conical bit of the spacecraft the astronauts actually rode in--was designed by destructive testing. Engineers at North American Aircraft (which was subsequently bought by Rockwell) set up a big pivot-arm that could swing an engineering mock-up of the command module through an arc that ended in what was basically a big swimming pool. Thus could they emulate the effects of splash-down.

The first tests were not encouraging--the capsule was effectively destroyed, squashed flat, and had it been occupied the people inside would have been killed. So the engineers went back to the drawing board and improved things, trying to find a design that would meet the weight-constraints and at the same time bring the astronauts safely back to Earth after their free-fall of a quarter of a million miles from the Moon.

That's one of the things that I didn't appreciate about the Apollo program, despite my long interest in space exploration, until I saw Apollo 13--that there was no orbital insertion on the way home, that it was like dropping a penny in a can from two-hundred-fifty-thousand miles up. No second chances.

And that is where humans do differ from insensate matter. Kipling's poem ends by making the point that we get second chances, we heal and learn and grow, even after we've been tested to destruction. Like wood and metal, we can fail. Unlike them, we can also hope.
Reading I read Neil Gaiman's Stardust yesterday, on Carolyn Croissant's recommendation. It's good: a lyrical fable, told with warmth that never descends into sentimentality or veers into the grotesque. I wasn't much taken with Gaiman's Neverwhere, and attributed the brilliance of Good Omens to Terry Pratchett, Gaiman's co-author. I'm a big Pratchett fan, although I have to admit that Gaiman leaves him in the dust as a stylist.

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