Vacuum effects Re: Drip Dry Phone

[Bill Ricker]

> Just curious - could subjecting a cell phone to vacuum (partial or
> otherwise) possibly cause things like capacitors to burst?

Good question!

I didn't recall seeing that as an issue in qualifying electronics for
AMSAT orbital payloads. They hand test and sort batteries, and remove
labels, but generally use COTS components.

/me googles ...

The _major_ limitation to using COTS components (Commercial Off The
Shelf) for orbital use is derating specs for heat distribution. No
convective cooling in space, so fuses and especially heat sinks are
de-rated. As regards Current limits, all components are treated like
overpriced fuses. Computer-style high-air-flow cooling doesn't work
out there. Astronomy and spy sats are more worried about component
off-gassing contaminating the optics; serious off-gassing can also
result in phantom thrusts, if it all escapes the frame at one corner.
All payloads are vacuum-baked before integration to check for vacuum
failure and ability to self-cool in vacuum ... to check for several
issues.

HOWEVER, vacuum testing does also check for what we might call popcorn
components. Bob, WB4APR, the Navy Academy microsat guy, said:

] VACUUM:  Go to your highschool and put your device under
] a Bell jar. Run it in vacuum a while.  Understand that
] you dont have air cooling anymore and so design for that.
] This is not space quality vacuum, but it will sure show
] any components that are going to blow up.  (though it
] wont show long term effects)...
[http://www.uk.amsat.org/ListArchives/amsat-bb/2003/msg04984.html]

So you might not want to run the Bell jar to its "hardest" (lame)
vacuum; you might want to bleed some dry air in, if trying this. For
dry air, put the bleed air intake hose at a window air conditioner's
output should do for this application -- not perfectly dry, but drier
than average.

This gives me an excuse to scrounge a Bell jar and vacuum pump next
time I see one at Hoss Traders !

--
Bill
n1vux at arrl.net bill.n1vux at gmail.com