[Space] Minutes 3/9/09

Mikolaj Habryn dichro at rcpt.to
Wed Mar 10 23:29:52 PST 2010


Will mylar hold much of a pressure differential? Or is the plan to
line a foam cavity with mylar? I'm not sure we need to worry too much
about heat loss through the foam, so I assume you're thinking of using
the mylar to prevent convective heat loss through the cracks? Is there
an easy way to prevent overheating as well?

Tapping the radio battery triggers my recovery paranoia; if we have
the weight budget to spare, I'd feel safer if we avoided tampering
with the position reporting dependencies. For all the SMS stuff worked
flawlessly last time, we'll be flying new software and if something
goes wrong with it, the radio beacon will be the only way to find the
payload.

m.

On Wed, Mar 10, 2010 at 8:07 PM, Christie Dudley <longobord at gmail.com> wrote:
> While antifreeze sounds like a neat idea, vaporization is not the problem so
> much as pressure/thinned atmosphere.  Think pv=nrt sort of deal, keeping in
> mind those phase charts from chemistry.
> Christie
> _______
> "We also briefly discussed having officers replaced by very small shell
> scripts." -- Noisebridge meeting notes 2008-06-17
>
> The outer bounds is only the beginning.
> http://www.flickr.com/photos/genriel/sets/72157623376093724/
>
>
> On Wed, Mar 10, 2010 at 7:57 PM, Albert Alexander
> <albert.alexander at gmail.com> wrote:
>>
>> Dear mod(s): Please disregard prev. email, accidentally sent as
>> non-member.
>>
>> Here's what we did and thought about on Tuesday.
>>
>>
>> THE FIGHT AGAINST CONDENSATION
>>
>> The internals of the payload will be contained in a mylar envelope. This
>> will provide a continuous thermal space that retains a LOT of heat (space
>> blankets claim something like 90%). I'm still investigating the energy
>> required to keep this space above dew point. That would prevent condensation
>> (hopefully).
>>
>> Still working on whether we should add a battery dedicated to warming. I'd
>> much rather tap a camera or radio battery to avoid the extra mass. On first
>> glance the radio battery looks like a prime candidate (low drain long life)
>> and is least likely to automatically shut off if it gets hot.
>>
>> Indium Tin Oxide film (ITO) is enroute courtesy of Bayview Optics. This
>> will heat the lenses with a thermistor circuit. There is a cup in my freezer
>> with antifreeze on it to test evaporation rate; this could be an acceptable
>> passive substitute for lens heaters depending on the distortion (its kinda
>> viscous).
>>
>> Camera circuits will be sealed with a conformal coating. Silicone looks
>> ideal. Hopefully will have some by Sunday for further testing.
>>
>>
>> THE PAYLOAD
>>
>> Styrofoam was cut and beveled with the classy new wire cutter. A camera
>> port has been added. The payload looks fairly anthropomorphic now. It needs
>> a name.
>>
>>
>> COMLINK
>>
>> Antenna was bound to carbon rods with thread.
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>
>
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