August 21, 2006
Bolt-on

Space.com is carrying this report on what would seem to be a routine maintenance item... the replacement of some securing bolts on a large antenna structure in space shuttle Atlantis's cargo bay. Routine, until you read this:

Earlier this week, [NASA shuttle program chief Wayne] Hale said that between six and eight engaged bolt treads are preferred for each bolt to ensure they will hold Atlantis’ 304-pound (137 kilogram) Ku-band antenna assembly fast during the eight and a half minute climb into orbit. Inspections found that only two of Atlantis’ four antenna bolts were suitably secured, though a survey of all three NASA shuttles found that some were attached by as little as two-thirds of a tread, he added.

Let's hear it for government project quality control! However, "treads" sounds like it might be different from "threads", so who knows, maybe it means something else entirely. All I can say is, if I found out only a quarter-turn of a bolt held something important on my car, I'd be pretty quick getting a longer bolt!

Posted by scott at August 21, 2006 12:07 PM

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Air Force Rule-of-Thumb was that any bolt had to have 2-2.5 threads protruding from it's nut. On top of that, we used mechanical locking nuts on damn near everything and safety-wired everything that could get near the engine.

Too bad they don't have a detail pic of the bolt in question. If it attaches to something that's not a thru-nut, I couldn't say how well what they're doing is attached.

Posted by: ron on August 21, 2006 12:40 PM
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