Text 27486, 44 rader
Skriven 2012-03-30 23:22:18 av mark lewis (1:3634/12)
Ärende: ORLY? sounds familiar in some ways ;)
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They couldn't find spray paint so they used tape on their 'ultra precise from
the bureau of standards' measuring bar.

"The guy was working under great stress because we were angry about costly
delays, and were threatening to put Kodak's mirror in the telescope, which
would have been humiliating for our contractor [Perkin-Elmer Corporation was
responsible for the mirror]. So he's working, he's really hurrying, he can't
find the spray paint. So instead he puts black tape on [the cap] and he takes
his X-Acto knife and cuts a hole. He doesn't notice he made a shiny little
burr. So he puts the thing on, the light hits the burr and goes  back up.

"His instructions were to move the thing in every direction to see if the
intensity of the light went down. So he moves it. Light goes onto the black
tape, onto the black tape, onto the black tape, down the hole [in the field
cap]. He assumes he got it centred."

However, the light had hit the burr instead of the top of the rod, which led
to a gross misplacing of the two mirrors."

They did test the mirror after it was finished but found it was half a wave
off.  They talked themselves into believing it just couldn't be.  A little
tester bias? :D

"So some people sat down and said, 'What's going on?" Pellerin recalls. "The
mindset was that the mirror can not be other than perfect. So something else
is happening. They concluded that the mirror was sagging under the force of
gravity in the three point mount rather than being on the bed of nails by
half a wave.

"Well it turned out that was wrong. But they rationalised, rationalised,
rationalised. What kind of minds does a project like Hubble attract? The
best. So [Allen] said, 'I want to understand why the smart guys working on it
didn't go dig in and find out what's going on.'"



http://www.techworld.com.au/article/420036/what_went_wrong_hubble_space_teles
cope_what_managers_can_learn_from_it_/?


-- 
)\/(ark - remove .my.foot to email me, capiche?

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