[NLC] Drip Dry Phone

Jim Kuzdrall gnhlug at intrel.com
Mon May 1 08:54:01 EDT 2006


On Sunday 30 April 2006 11:42 pm, Bill Ricker wrote:
> >     I can't think of any electronic component that will "burst" at
> > vacuum.  After all, it is only 14.7 psi pressure change at most -
> > even if you pump down below a micron.  You get down to 8 psi
>
> I don't know of any specifically, but if Bob Bruninga, WB4APR, one of
> the microsat developers (for US Naval Academy and APRS+AMSAT), is
> concerned with testing for popping components as well as heat budget
> when building cheap satellites from COTS components, it's probably a
> real concern...

    On the equipment I designed for SkyLab and the International Space 
Station, the specs didn't mentioned gas pressure damage.  But they were 
very, very concerned about out-gassing.

> Unlike... COTS components aren't designed to avoid air inclusions...
> As the original question posed, capacitors would be specific...

    For the cell phones and all modern equipment, the capacitors would 
be multilayer ceramics, tantalum, or stacked film surface-mount 
components.  These manufacturing processes introduce no air-filled 
voids.

    I would think the strong epoxy overcoats themselves would easily 
withstand 14 psi in such small components.  The large size, 1206, 
has .017 sqin internal area, for 4oz total pressure.  In the old days, 
with wrapped film and foil tubular caps made in open atmosphere, there 
would more likely be bubbles to leak out.

> As per Mt. Rainier, how long do you keep your personal electronics at
> the summit? ...

    True, if you really want to burst something you would have to get up 
Mt. Rainier much faster than I can climb.

    The AMSATs are a great project.  I haven't been active in ham radio 
since the sixties, but it was once my great passion.  I remember Oscar 
I.  If fact, I was up listening the night Sputnik went up.  Lots of ham 
chatter that night.

    But I actually like playing with Linux and computers more now days.  
(See, I brought the discussion back on topic.)

Jim Kuzdrall



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