Author Topic: Cold Soak Thoughts?  (Read 1632 times)

Offline bmlbrandsllc

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Cold Soak Thoughts?
« on: 01/26/2012 12:37 PM »
I am just curious as to how would you engineer a small rover to survive the lunar night?  Any thoughts or ideas?
« Last Edit: 01/26/2012 04:41 PM by Chris Bergin »
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Offline Jim

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Re: Cold Soak Thoughts???
« Reply #1 on: 01/26/2012 12:52 PM »
RHU's

Offline Lee Jay

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Offline dcporter

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Re: Cold Soak Thoughts???
« Reply #3 on: 01/26/2012 02:27 PM »
I'm certain it's a long list, but what parts of a current-gen rover wouldn't restart after an overnight soak without a RHU?
« Last Edit: 01/26/2012 02:29 PM by dcporter »

Offline kevin-rf

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Re: Cold Soak Thoughts???
« Reply #4 on: 01/26/2012 02:53 PM »
I think it is more an issue of thermal fatigue on components (esp. electrical). Going from those temps to warmer temps and back plays havoc on things like solder joints, socket connections, bearings, batteries, cracking wire insulation in motors and transformers, ect. I am always surprised that the temps break things, but it is hard to argue with what really happens. 
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Offline synchrotron

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Re: Cold Soak Thoughts???
« Reply #5 on: 01/26/2012 02:54 PM »
Dunno if this is of interest.  The Boeing folks at Huntington Beach have done quite a bit of work looking at electronics that operate (not just survive) at cryogenic temperatures under high radiation.  Single event effects are exacerbated, but TID can be lower.  The promise there is reduced shielding and more decentralized architectures because you can ditch the warm electronics boxes. Pushes the fabs to silicon germanium though.  There are a few papers by Leora Peltz.

Offline Jim

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Re: Cold Soak Thoughts???
« Reply #6 on: 01/26/2012 04:11 PM »
Batteries I believe are big issue.

Offline dcporter

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Re: Cold Soak Thoughts?
« Reply #7 on: 01/26/2012 05:10 PM »
Batteries that makes sense. Ditto temperature breakage. All that applies to spacecrafts as well I assume? Sounds like some good targets for small GingrichPrizes.

Offline Blackstar

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Re: Cold Soak Thoughts?
« Reply #8 on: 01/26/2012 05:15 PM »
Batteries that makes sense. Ditto temperature breakage. All that applies to spacecrafts as well I assume? Sounds like some good targets for small GingrichPrizes.

Why use prizes? Traditional development methods work just fine.


Offline Patchouli

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Re: Cold Soak Thoughts???
« Reply #9 on: 01/26/2012 05:22 PM »
RHU's

http://en.wikipedia.org/wiki/Radioisotope_heater_unit

Lunokhod use a chunk of Polonium 210 to keep from it's self from freezing.
The setup was pretty ingenious in it's simplicity.
 The electronics were contained inside an pressurised vessel and the solar cells were in a lid that closed over the vehicle to keep it warm.
This also protected to solar cells from the cold.

« Last Edit: 01/26/2012 05:26 PM by Patchouli »

Offline Robotbeat

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Re: Cold Soak Thoughts?
« Reply #10 on: 01/26/2012 05:34 PM »
Batteries that makes sense. Ditto temperature breakage. All that applies to spacecrafts as well I assume? Sounds like some good targets for small GingrichPrizes.

Why use prizes? Traditional development methods work just fine.
Because "traditional development" will pretty much always pick the least-risky option, which in this case is probably RHUs, with all the overhead and expense that involves. No real advancement is likely. The advantage of prizes is that you have the ability to attract multiple groups willing to take the risk of jumping across the TRL valley of death.

Really small prizes or SBIR grants are a pretty cheap way to develop electronics that can withstand deep cryogenic temperatures. The testing can be done on the ground with University or small business-level infrastructure.
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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