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Article #143Re: nasa-celebrates-successful-mars-landing
From: Jon Kirwan
Date: Tue, 07 Aug 2012 23:57
Date: Tue, 07 Aug 2012 23:57
37 lines
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2986 bytes
On Wed, 08 Aug 2012 09:42:05 +1000, Adrian Jansen <adrian@qq.vv.net> wrote: >On 8/8/2012 7:04 AM, Jon Kirwan wrote: > >>>> >>>> Which reminds me of another thing. How do they convect the >>>> internally generated heat away. I recall hearing about >>>> multiple power systems, operating around 32V at near 2A. More >>>> than one. This power must be convected/conducted away -- no >>>> way they want to radiate it. I wonder if they push it >>>> (costing more heat) towards a vane or arm and drag it around >>>> on the surface to get rid of it? >>> >>> The atmosphere won't help much. >>> >>> Why not? Thermal conductivity of air is pretty much constant till you >>> get below 1 Torr or so. Wiki says the mean pressure on mars is about >>> 0.1 psi, which is ~5 torr. >> >> Good point. >> > >In earth atmosphere, I understand most heat above around 300K ( 'room' >temp ) is carried by radiation and convection. Conduction is a minor part. > >No idea what convection is like at 5 torr in a CO2 atmosphere, but I >suspect its a lot lower. Then that begs the question, again. Perhaps George spoke too soon. I'll go dig. I'm ignorant and don't like the feeling. Jon
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From: Jon Kirwan <jonk@infinitefactors.org>
Newsgroups: sci.electronics.design,aus.electronics,comp.arch.embedded
Subject: Re: nasa-celebrates-successful-mars-landing
Date: Tue, 07 Aug 2012 16:57:32 -0700
Organization: Infinite Factors
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