To: atm{at}shore.net
From: Andy Saulietis 
Reply-To: Andy Saulietis 


Re HST optics screwup:

Maybe more urban legends, but IMHO a focault test by itself on a fast
hyperbolic primary would be more difficult than the null corrector actually
used. I understand that the DOD had a 100" dia flat available for null
testing the complete system, which could then be done with a simple Focault
test, but the logistiocs cost of actually doing this would have been
*formidable* & added weeks if not months to the already-behind schedule.
There's also the problem of gravity distortion of the assembled optics
& its effect on the 'simple' focault test.

In my experience at NASA building/testing star trackers, we always double
checked tests and procedures using different test equipment where
possible..this was usually a problem for the bean-counters..;) The HST
problem might have been alleviated if an independent outside group (such as
NASA) had built their own null corrector & done tests with it also..the
cost of this would have been *minimal* compared to the consequences of what
actually was done.











Andy Saulietis
ISS Enterprises
PO Box 19
Mayhill NM 88339


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