Re: Why not on the moon?

In article <43bbf341$0$10079$ba620dc5@xxxxxxxxxxxxxxxxxxx>,
Roland <roland_lemmersZPEMM@xxxxxxxxx> wrote:
>> Staying operational once there is even worse. A lunar night is two weeks
>> of no sunlight and very low temperatures. I don't believe an electronics
>> package has ever survived that without, at least, radio-isotope heaters.
>
>Would it be possible to design a transponder to work at these low
>temperatures? I'm thinking of those HEMT transistors cooled to 80K used
>in the deep space network. Keep in the shade during the lunar day and it
>wouldn't see huge swings in temperature.

Unfortunately, you'd have to shade it not only against the Sun, but
against the warm lunar surface all around it. And the shades too get
warm, although you can fight that with surface coatings and multiple
layers.

That aside, it's not a bad idea. Quite aside from all the fun ways you
can exploit the lower temperature, a lot of ordinary electronics
apparently will work reasonably well if cooled to LN2 temperatures...
*once*. It's cycling that kills it, often very quickly.

But I fear I don't see any easy way of keeping it cold during the day.
Hard, complicated ways, but no easy ones.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. | henry@xxxxxxxxxxxxx
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