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Low Quality Alloy Cause of Shuttle Main Tank Issue 118

BJ_Covert_Action writes "NASA engineers have finally discovered the root cause of the cracks that have been found on space shuttle Discovery's main external tank. The main tank, one of the 'Super Lightweight Tank' models developed by Lockheed-Martin, employs an aluminum-lithium alloy developed by Lockheed-Martin specifically for this application. The new alloy is used in various structural stringers throughout the SLWT design. Unfortunately, the batch of this alloy used in the tank that is currently mated with the Discovery shuttle appears to be of low quality. The alloy used in the stringers has a 'mottled' appearance, compared to the nominal appearance typically used in the main tank stringers (see picture in article). This appearance is indicative of a fracture threshold that is significantly lower than typical. NASA has determined, through testing, that this low grade alloy has only 65% of the fracture strength of the nominal alloy typically used. NASA engineers have devised a potential fix to the problem that they are currently testing to ensure the repair will cause no unintended consequences. NASA plans to have the Discovery shuttle ready to launch again by February 24th, 2011."

Comment Re:Missing Option (Score 1) 507

This is the only upside to living in one of the drier parts of the country. Hardly ever any cloudy days, so our solar panels offset our usage even in the winter, opening the windows at night in the summer cools the house down enough for the whole day, and our clothes dryer hardly sees any use since I discovered that even things I forgot in the washer were bone dry the next day with no smell. Almost makes up for the sinus-searing dryness. Almost.

I grew up in the South and firmly believe that AC is the only thing that made the area properly livable. The real sin is that there's plenty of people here who run their AC full-time, too.

Comment Poor summary (Score 1) 152

the finding may be based on something as simple as poor sample washing to remove phosphate contamination.

This conflates two problems mentioned in the article: possible poor washing of arsenic off the DNA, since it apparently likes to glom onto things, and trace amounts of phosphorus in the salts they fed the bacteria that were trying to starve of phosphorus.

Comment Extraordinary? (Score 1) 1

Perhaps only in scale. Or are they really expressing surprise that any journalists are dirtying their hands by working with big bad Wikileaks? There wouldn't be any news if journalists insisted on only talking with the kind of people you wouldn't mind your daughter bringing home.

The really interesting bit is this:

Kauffmann of Le Monde said there was no financial agreement with WikiLeaks.

"Never has anyone asked to pay anything, and if they had, we probably — certainly — would not have done so, because we never pay for news."

I've probably — no wait, certainly — wouldn't have stolen candy from that baby. I never do that kind of thing.

Comment Re:Marcus Aurelius (Score 1) 473

Indeed, my translation explicitly excludes the possibility of there being no gods right after considering the idea, but otherwise roughly follows the same idea:

In all you do or say or think, recollect that at any time the power of withdrawal from life is in your own hands. If gods exist, you have nothing to fear in taking leave of mankind, for they will not let you come to harm. But if there are no gods, or if they have no concern with mortal affairs, what is life to me, in a world devoid of gods or devoid of Providence? Gods, however, do exist, and do concern themselves with the worlds of men.

My 1964 translation, however, doesn't bear the slightest resemblance to the version on wikisource, not just in style but in meaning, so that it's hard to believe it's even based on the same source.

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