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CX2SA > SATDIG 18.11.09 22:16l 626 Lines 22226 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: PocketSat, RIP ??? (Amir Findling K9CHP)
2. Re: Satellite Thermal Lesson (Edward Cole)
3. Re: Satellite Thermal Lesson (Edward Cole)
4. Re: PocketSat, RIP ??? (D. Craig Fox)
5. Re: Satellite Thermal Lesson (Robert Bruninga)
6. Re: Satellite Thermal Lesson (Graham Shirville)
----------------------------------------------------------------------
Message: 1
Date: Wed, 18 Nov 2009 11:53:51 -0500
From: Amir Findling K9CHP <sarlabs@xxxxx.xxx>
Subject: [amsat-bb] Re: PocketSat, RIP ???
To: "amsat-bb@xxxxx.xxx >> Amsat BB" <amsat-bb@xxxxx.xxx>
Message-ID: <4B04269F.7000903@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Unfortunately the $1.99 version is only good for 40 fixed satellites
none of which are of any use to ham radio operators (other than the
ISS). You need to buy the full version to have access to your choice of
satellites, and that version is more costly, about $24.00 or so.
* 73 de K9CHP Amir Findling, Member ARRL, ARRL/ W5YI VE, WAC, WAS, DXCC
* www.K9CHP.net <http://www.k9chp.net>
Blog: http://k9chp.blogspot.com <http://k9chp.blogspot.com/>
* Senior K9 Handler
* K9 Certification Tester, NYS Federation of SAR Teams
* 1st Special Response Group (1SRG)
Clint Bradford wrote:
> Unfortunately, I heard "one of us" report last week that "PocketSat
> isn't really popular any more, with the demise of the Palm computing
> platform ... "
>
> That's woefully incorrect on many fronts.
>
> Palm users are plentiful, and Jim is still supporting us. PocketSat+
> is still the best Palm-platform satellite tracking software available,
> IMHO. Support still at ...
>
> http://www.bigfattail.com
>
> But Jim has not let his programming skills stagnate. We now have
> PocketSat3 for the Apple iPhone and iPod touch devices. It provides
> gorgeous screen graphics for our passes. Available in the Apple Store.
> Docs and support at Jim's new site at ...
>
> http://www.pocketsat.com/
>
> It works marvelously on my new 32GB iPod touch. AMSAT's keps are one
> of the four default sets for painless download. Recently added is a
> "View Constellation" mode - which overlays your view of the heavens on
> a sat pass.
>
> There are several "satellite trackers" in the Apple Store ... from
> free to $.099 to a few bucks. I have tried five others. NONE of them
> come close to the feature set, ease of use, and product support that
> one receives with PocketSat3.
>
> Clint Bradford, K6LCS
> http://www.work-sat.com
> 909-241-7666
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
------------------------------
Message: 2
Date: Wed, 18 Nov 2009 07:55:20 -0900
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Satellite Thermal Lesson
To: kk5do@xxxxx.xxxx bruninga@xxxx.xxx
Cc: amsat-bb@xxxxx.xxx
Message-ID: <200911181655.nAIGtKKh036118@xxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:46 AM 11/18/2009, Bruce wrote:
>On 11/18/2009 8:34 AM, Robert Bruninga wrote:
> > Lesson learned on Satellite Thermal.
> >
> > For years, we have been trying to demonstrate to students the
> > extreme differences in Temperature of a satellite based simply
> > on its color. In space, far from earth, here is what you should
> > get for three identical satellites:
> >
> > Black will be about +55 deg F
> > White will be about -60 deg F
> > Aluminum will be about +225 deg F
>snip...
>
>This was sent by Bob on April 26, 1996. I found it interesting and kept it.
>
>KEEPING ELECTRONICS COOL IN THE SUN.
>
>WHile building a GPS unit for mounting on my dashboard and noting the
>comming summer months, I looked up the difference in absorption and
>emissivity for Aluminum, Black paint, and white paint. Satellite builders
>are well aware of these facts, but many of us landlubbers are not.
>
>ALUMINUM will get 30 TIMES hotter than WHITE paint! (in a vacuum)
>
>The following table is for a vacuum and accounts for RADIATIVE effects. It
>does not account for convective or conductive cooling (air)..
>
> Absorbtion Emissivity Ratio Temp C
>
>ALUMINUM .4 .03 11:1 400
>STEEL .6 .4 3:2 150
>BLACK PAINT .9 .9 1:1 110
>WHITE PAINT .25 .85 1:3 72
>
>Most people are aware that Black gets hotter than white, but the fact that
>bright, reflective, shinny Aluminum gets 10 times hotter than BLACK is a
>surprise to most people...
>
>So, if it sits in the sun, paint it white! If you dont believe this, put
>an aluminum baking sheet in the sun. I baked my first roof mount GPS
>stand alone tracker thinking that the upside down baking pan would reflect
>the sun... WRONG! Painted it white and it is now as cool as a cucumber.
>
>The difference in Aluminum is the POOR EMISSIVITY at infrared. It can't
>radiate the heat away...
>
>
>
>
>
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Yep, a hard lesson for the uninitiated working in the desert in
summer: lay those shiny metal tools in the sun for ten minutes and
you better wear gloves to pick em up. They get extremely hot and
will burn skin. We always took care to lay the tools in shade or
cover them with a cloth.
Regarding painting dishes white, all the dishes at Goldstone were
painted white. What you may find interesting was that receive
waveguide was painted white while transmit waveguide was
flat-black. The heat buildup in the transmit waveguide required
water-cooling by silver soldering cooling tubes to the surface of the
waveguide. I suppose the black color aided black-body radiation.
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
500-KHz/CW, 144-MHz EME, 1296-MHz EME
DUBUS Magazine USA Rep dubususa@xxxxxxx.xxx
======================================
------------------------------
Message: 3
Date: Wed, 18 Nov 2009 07:58:54 -0900
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Satellite Thermal Lesson
To: kk5do@xxxxx.xxxx bruninga@xxxx.xxx
Cc: amsat-bb@xxxxx.xxx
Message-ID: <200911181658.nAIGws59036287@xxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:46 AM 11/18/2009, Bruce wrote:
>On 11/18/2009 8:34 AM, Robert Bruninga wrote:
> > Lesson learned on Satellite Thermal.
> >
> > For years, we have been trying to demonstrate to students the
> > extreme differences in Temperature of a satellite based simply
> > on its color. In space, far from earth, here is what you should
> > get for three identical satellites:
> >
> > Black will be about +55 deg F
> > White will be about -60 deg F
> > Aluminum will be about +225 deg F
>snip...
>
>This was sent by Bob on April 26, 1996. I found it interesting and kept it.
>
>KEEPING ELECTRONICS COOL IN THE SUN.
>
>WHile building a GPS unit for mounting on my dashboard and noting the
>comming summer months, I looked up the difference in absorption and
>emissivity for Aluminum, Black paint, and white paint. Satellite builders
>are well aware of these facts, but many of us landlubbers are not.
>
>ALUMINUM will get 30 TIMES hotter than WHITE paint! (in a vacuum)
>
>The following table is for a vacuum and accounts for RADIATIVE effects. It
>does not account for convective or conductive cooling (air)..
>
> Absorbtion Emissivity Ratio Temp C
>
>ALUMINUM .4 .03 11:1 400
>STEEL .6 .4 3:2 150
>BLACK PAINT .9 .9 1:1 110
>WHITE PAINT .25 .85 1:3 72
>
>Most people are aware that Black gets hotter than white, but the fact that
>bright, reflective, shinny Aluminum gets 10 times hotter than BLACK is a
>surprise to most people...
>
>So, if it sits in the sun, paint it white! If you dont believe this, put
>an aluminum baking sheet in the sun. I baked my first roof mount GPS
>stand alone tracker thinking that the upside down baking pan would reflect
>the sun... WRONG! Painted it white and it is now as cool as a cucumber.
>
>The difference in Aluminum is the POOR EMISSIVITY at infrared. It can't
>radiate the heat away...
>
>
>
>
>
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Second thought on this: I painted my eme dish flat-gray for visual
environmental reasons, but the color aids melting ice/snow from the
surface. It was previously white.
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
500-KHz/CW, 144-MHz EME, 1296-MHz EME
DUBUS Magazine USA Rep dubususa@xxxxxxx.xxx
======================================
------------------------------
Message: 4
Date: Wed, 18 Nov 2009 10:07:19 -0800
From: "D. Craig Fox" <DFox@xxxxxx.xxx>
Subject: [amsat-bb] Re: PocketSat, RIP ???
To: <amsat-bb@xxxxx.xxx>
Message-ID:
<A8E6E57AFA652D419A823F42AD6ACBDE02EBA406@xxxxxxxxx.xxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
As I posted sometime back, I have been using free Satellite Tracker on my
iphone. I cannot imagine any tracking program could be easier to use. The
graphics are rather crude compared to ProSat but it is extremely simple to
use, updates easily and shows information for subsequent passes of any ham
sat. This program is extremely convenient when I choose to leave the
comfort of my TS2000 and yagis, and go handheld QRP with the D7 and Elk.
Just my $.02
73s
Craig
N6RSX
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxxxx
Behalf Of Amir Findling K9CHP
Sent: Wednesday, November 18, 2009 8:54 AM
To: amsat-bb@xxxxx.xxx >> Amsat BB
Subject: [amsat-bb] Re: PocketSat, RIP ???
Unfortunately the $1.99 version is only good for 40 fixed satellites
none of which are of any use to ham radio operators (other than the
ISS). You need to buy the full version to have access to your choice of
satellites, and that version is more costly, about $24.00 or so.
* 73 de K9CHP Amir Findling, Member ARRL, ARRL/ W5YI VE, WAC, WAS, DXCC
* www.K9CHP.net <http://www.k9chp.net>
Blog: http://k9chp.blogspot.com <http://k9chp.blogspot.com/>
* Senior K9 Handler
* K9 Certification Tester, NYS Federation of SAR Teams
* 1st Special Response Group (1SRG)
Clint Bradford wrote:
> Unfortunately, I heard "one of us" report last week that "PocketSat
> isn't really popular any more, with the demise of the Palm computing
> platform ... "
>
> That's woefully incorrect on many fronts.
>
> Palm users are plentiful, and Jim is still supporting us. PocketSat+
> is still the best Palm-platform satellite tracking software available,
> IMHO. Support still at ...
>
> http://www.bigfattail.com
>
> But Jim has not let his programming skills stagnate. We now have
> PocketSat3 for the Apple iPhone and iPod touch devices. It provides
> gorgeous screen graphics for our passes. Available in the Apple Store.
> Docs and support at Jim's new site at ...
>
> http://www.pocketsat.com/
>
> It works marvelously on my new 32GB iPod touch. AMSAT's keps are one
> of the four default sets for painless download. Recently added is a
> "View Constellation" mode - which overlays your view of the heavens on
> a sat pass.
>
> There are several "satellite trackers" in the Apple Store ... from
> free to $.099 to a few bucks. I have tried five others. NONE of them
> come close to the feature set, ease of use, and product support that
> one receives with PocketSat3.
>
> Clint Bradford, K6LCS
> http://www.work-sat.com
> 909-241-7666
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
NOTICE: This communication may contain privileged or other confidential
information. If you are not the intended recipient of this communication, or
an employee or agent responsible for delivering this communication to the
intended recipient, please advise the sender by reply email and immediately
delete the message and any attachments without copying or disclosing the
contents. Thank you.
------------------------------
Message: 5
Date: Wed, 18 Nov 2009 13:25:14 -0500
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Satellite Thermal Lesson
To: "'Idle-Tyme'" <nss@xxx.xxx>, <kk5do@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <06BAE82A2CCB44EDBF4B4C3DCC3EA358@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Top Post:
The huge difference in Aluminum, White and Black will only be
seen in space where there is only radiation heat transfer and no
Conduction and no convection. On Earth, in air, convection
cooling dominates. These numbers only apply to Radiation heat
transfer.
Black absorbs 90% of sunlight and emits 90% heat - nice
White absorbs 30% of sunlight and emits 90% heat - cool
Al... Absorbs 30% of sunlight and emits 3% heat - gets hot!
BUT, if you have air, and especially moving air, then anything
can get rid of most of its heat to the air which is a larger
effect.
Second Lesson: BUT "natural convection" which we all know cools
things... depends on gravity! Remove gravity, and there is no
natural convection... That is why you have to wear earplugs on
the Space Station... Because every little thing has to have a
FAN to move the air. Without it, things and the air around them
just get hotter and hotter...
> -----Original Message-----
> From: Idle-Tyme [mailto:nss@xxx.xxxx
> Sent: Wednesday, November 18, 2009 11:33 AM
> To: kk5do@xxxxx.xxx
> Cc: bruninga@xxxx.xxxx amsat-bb@xxxxx.xxx
> Subject: Re: [amsat-bb] Re: Satellite Thermal Lesson
>
> Morning Bruce and everyone.
>
> This really amazes me. Now is these spec's below for in a
> vacuum of space? Or on the earth's surface with Air.
>
> Reason asking is, if this is indeed true, then why does
> every solar heat panel be painted black?
>
> Not air panels by the numbers given below an Air panel being
> made black is near perfect it re radiates almost everything
> it absorbs.
>
> But a closed loop liquid system where tubing is in the panel
> with fins attached to gather the energy. absorb it, and let
> the liquid take the heat away.
>
> Every one of these are also painted black.
>
> in this case wouldn't it be better to leave it bare aluminum?
> for it absorbs it but doesn't re radiate it away so it has
> more efficiency of getting the heat into the liquid.
>
> anyone?
>
> Joe WB9SBD
>
>
> <file:///C:/Documents%20and%20Settings/Joe%20Mayenschein/My%20
> Documents/Sig/CLEAN-IDLE-TYME-LOGO-100-50.jpg>
> The Original Rolling Ball Clock
> http://www.idle-tyme.com
>
>
>
>
> Bruce wrote:
>
> On 11/18/2009 8:34 AM, Robert Bruninga wrote:
>
>
> Lesson learned on Satellite Thermal.
>
> For years, we have been trying to demonstrate
> to students the
> extreme differences in Temperature of a
> satellite based simply
> on its color. In space, far from earth, here
> is what you should
> get for three identical satellites:
>
> Black will be about +55 deg F
> White will be about -60 deg F
> Aluminum will be about +225 deg F
>
>
> snip...
>
> This was sent by Bob on April 26, 1996. I found it
> interesting and kept it.
>
> KEEPING ELECTRONICS COOL IN THE SUN.
>
> WHile building a GPS unit for mounting on my dashboard
> and noting the
> comming summer months, I looked up the difference in
> absorption and
> emissivity for Aluminum, Black paint, and white paint.
> Satellite builders
> are well aware of these facts, but many of us
> landlubbers are not.
>
> ALUMINUM will get 30 TIMES hotter than WHITE paint!
> (in a vacuum)
>
> The following table is for a vacuum and accounts for
> RADIATIVE effects. It
> does not account for convective or conductive cooling
(air)..
>
> Absorbtion Emissivity Ratio Temp C
>
> ALUMINUM .4 .03 11:1 400
> STEEL .6 .4 3:2 150
> BLACK PAINT .9 .9 1:1 110
> WHITE PAINT .25 .85 1:3 72
>
> Most people are aware that Black gets hotter than
> white, but the fact that
> bright, reflective, shinny Aluminum gets 10 times
> hotter than BLACK is a
> surprise to most people...
>
> So, if it sits in the sun, paint it white! If you dont
> believe this, put
> an aluminum baking sheet in the sun. I baked my first
> roof mount GPS
> stand alone tracker thinking that the upside down
> baking pan would reflect
> the sun... WRONG! Painted it white and it is now as
> cool as a cucumber.
>
> The difference in Aluminum is the POOR EMISSIVITY at
> infrared. It can't
> radiate the heat away...
>
>
>
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are
> those of the author.
> Not an AMSAT-NA member? Join now to support the amateur
> satellite program!
> Subscription settings:
> http://amsat.org/mailman/listinfo/amsat-bb
>
>
> ________________________________
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 9.0.707 / Virus Database: 270.14.72/2511 -
> Release Date: 11/18/09 01:50:00
>
>
>
>
------------------------------
Message: 6
Date: Wed, 18 Nov 2009 19:46:42 -0000
From: "Graham Shirville" <g.shirville@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Satellite Thermal Lesson
To: <bruninga@xxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <21F0C60BA6CC49F2A1522983E272A64A@xxxxxxx.xxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Bob,
Interesting!
As it happens we have included a material science experiment/demonstration
into the requirements for the educational payload of FUNcube. It will
actually measure the temperature of two pieces of aluminium facing the same
direction in space.
We had already concluded to have a black anodised finish on one and a silver
finish on the other but we will now ensure that a final careful cleaning
process is undertaken just before the satellite is placed in the deployer.
A very timely "heads up" for us.
Many thanks
Graham
G3VZV
----- Original Message -----
From: "Robert Bruninga" <bruninga@xxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Wednesday, November 18, 2009 2:34 PM
Subject: [amsat-bb] Satellite Thermal Lesson
> Lesson learned on Satellite Thermal.
>
> For years, we have been trying to demonstrate to students the
> extreme differences in Temperature of a satellite based simply
> on its color. In space, far from earth, here is what you should
> get for three identical satellites:
>
> Black will be about +55 deg F
> White will be about -60 deg F
> Aluminum will be about +225 deg F
>
> (from memory anyway)... But we have never been able to see the
> extreme temperature of the aluminum in our vacuum chamber. Of
> course, we are not using a SUN, but an incandescent lamp which
> has 95% of its radiation as heat and only 5% as light, so we
> attribtuted our wishy-washy results as due to the lack of real
> solar spectrum.
>
> This year, we finally have a Tvac chamber that has a liguid
> nitrogen cold plate so we can actually better simulate the
> blackness (and cold) of space.. Again, same result. Aluminum
> was about the same as black. This was a frustrating result from
> this new chamber.
>
> Then I noticed the fingerprints on the aluminum. I cleaned the
> aluminum with a swab of alcohol to eliminate all the surface
> contaminants, and fingerprints and re-did the test...
>
> BINGO. Now the temperature of the aluminum goes up and off
> scale HOT, way way different from the black or White. And now
> the WHITE also goes colder..
>
> So just the thinneest innvisible layer of surface contamination
> completely changed the thermal emissivity of the Aluminum. And
> we all know this anyway, since "low-E" coatings of glass and
> other materials is now so common. It is only the outer surface
> of molecules that set the absorbtivity and emissivity... And
> the differnce between Black and Aluminum is 30-to-1 (if the
> aluminum is clean)... That's why we wrap baked potatos in
> Aluminum foil! (don't use greasy hands)...
>
> Of course we always clean our actual spacecraft to clean-room
> conditions before flight, so this does not impact our on-orbit
> results, but it sure does make a difference in the lab when we
> are demonstrating absorbtivity and emissivity in the chamber
> with samples handled by the students!
>
> When I get a chance, Ill post the results...
>
> Bob, WB4APR
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 4, Issue 613
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