RE: [ATM] Why not metal mirrors? (was Beryllium)

[Andy Saulietis <iss@pvtnetworks.net>]

Re aluminum mirrors,


>The real trick here is to polish out the aluminum.  NASA did this by diamond
>turning the surface and then polishing it out with india ink.   I think 
>the best
>idea is to cast in the rough curve,  as I don't have a precision lathe.

Aluminum mirrors can work if the alloy is 6061 or similar..I've
seen pretty good polish via diamond turning. Cast aluminum has a
pretty coarse crystalline structure and doesn't polish well unless
plated with something else.

Back in Apollo, we used sintered Beryllium for small mirrors
overcoated with a proprietary plating of something called
'Kanigen' that polished well. *Expensive* though, especially since
the optics were used on one mission & then dunked into sea
water...





Andy Saulietis
ISS Enterprises
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Mayhill NM 88339


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