austin_dern (austin_dern) wrote,
austin_dern
austin_dern

Fortune's always hiding

I walked home rather than wait for the campus bus because I attended a late lecture from Dr Douglas D Osheroff on the Columbia accident investigation. The talk was slightly dragged down by an introduction that went on way too long (Osheroff won a Nobel Prize in Physics for his part in discovering superfluid helium-3 and was on the Columbia Accident Investigation Board; I'd think that enough introduction. They listed, near as I can tell, every award he's won), but it was quite worth it.

I didn't know before that they had zinc problems with the launch pads. I also didn't realize that the current theory of why the external tank shed foam wasn't actually proven to occur. It's not just aerodynamic heating, based on the recorded times of past incidents; but estimates of how much internal friction heating can be expected are shaky. Also fascinating but not explained: five of the seven incidents in which foam is known to have shed from the left bipod ramp (the strut leading to the Orbiter's nose) were Columbia launches. Also no shedding incidents from the right bipod ramp are recorded; it's thought a liquid oxygen pipe inside the hull there prevents it. Fascinating material.

Plus he had high-speed movies of that famous test-firing of a foam panel at a leading-edge panel reconstruction. The one from outside was amazing enough; he also had a movie from inside the simulated wing. (They used a standard ``chicken gun,'' used for airplane testing, for the foam impact tests.)

Trivia: There are 22 Reinforced Carbon-Carbon panels on the leading edge of each Space Shuttle wing. Source: Space Shuttle: The History of the National Space Transportation System: The First 100 Missions, Dennis R. Jenkins.

Currently Reading: The Rise of the Great Powers 1648-1815, Derek McKay and H.M. Scott.

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