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CX2SA > SATDIG 21.07.14 01:48l 885 Lines 32639 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: ANS-199 AMSAT News Service Special Bulletin - AMSAT
Fox-1C Launch Opportunity Announced (John Becker)
2. Triton-1 (Andrew Glasbrenner)
3. Re: ANS-199 AMSAT News Service Special Bulletin - AMSAT
Fox-1C Launch Opportunity Announced (Paul Stoetzer)
4. Re: WD9EWK from FN56 starting @ 1727 UTC today... (Paul Stoetzer)
5. Re: WD9EWK from FN56 starting @ 1727 UTC today... (Bill (W1PA))
6. Re: WD9EWK from FN56 starting @ 1727 UTC today...
(Andrew Glasbrenner)
7. Re: ANS-199 AMSAT News Service Special Bulletin - AMSAT
Fox-1C Launch Opportunity Announced (Clayton Coleman)
8. Re: ANS-199 AMSAT News Service Special Bulletin -AMSAT Fox-1C
Launch Opportunity Announced (Tom Schuessler)
9. Important information concerning the AMSAT-NA ballot package
(Alan)
10. What to do and how to do it? (Rich/wa4bue)
11. Re: going digital (Phil Karn)
12. Re: ANS-199 AMSAT News Service Special Bulletin - AMSAT
Fox-1C Launch Opportunity Announced (Robert Bruninga)
13. Re: ANS-199 AMSAT News Service Special Bulletin - AMSAT
Fox-1C Launch Opportunity Announced (Robert Bruninga)
----------------------------------------------------------------------
Message: 1
Date: Sun, 20 Jul 2014 12:19:10 -0500
From: John Becker <w0jab@xxxxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
Message-ID: <53CBFA0E.2090209@xxxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 7/20/2014 12:00 PM, Paul Stoetzer wrote: IN PART
> The bottom line is that AMSAT-NA needs a significant boost in
> membership and visibility and that boost needs to be soon.
I gave up on AMSAT when it seemed that the main afford was put into
FM in and FM out satellites. Membership ran out many (15) years ago.
John
------------------------------
Message: 2
Date: Sun, 20 Jul 2014 13:36:39 -0400
From: "Andrew Glasbrenner" <glasbrenner@xxxxxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Triton-1
Message-ID: <04eb01cfa441$29c17ed0$7d447c70$@xxx>
Content-Type: text/plain; charset="us-ascii"
Anyone have any updated news on this one? I haven't heard much since launch.
I'm curious how the primary mission is going.
73, Drew KO4MA
------------------------------
Message: 3
Date: Sun, 20 Jul 2014 13:47:40 -0400
From: Paul Stoetzer <n8hm@xxxx.xxx>
To: John Becker <w0jab@xxxxxxxxx.xxx>
Cc: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
Message-ID:
<CABzOSOrEKLCgBSOaobC2js0R493WuLO2dswZ5ZkHLxeRviyZug@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
The Fox-1 series of satellites will lead to the Fox-2 series with many
more interesting modes and capabilities. Yes, the priority is on
building and launching the Fox-1 series, but a good portion of that
work will be done by next year and then the lessons learned can be
applied to constructing and launching the Fox-2 series.
The reality is, of course, that FM satellites are extremely popular. I
have read through much of the AMSAT-BB archives and I find a ton more
posts about grid and country activations from back when AO-51 was
alive than what you see now. Getting on the linear satellites is not
expensive or complicated at all, but for whatever reason, we just have
not been able to communicate that it's both fun, extremely rewarding,
and that won't break the bank doing it to the amateur radio community
as a whole, so for those of us who enjoy chasing grids, states,
provinces, DX, etc, we do rely on the availability of FM satellites to
activate those areas.
Also remember that AMSAT is a membership organization. If members are
not happy with the direction of the organization, they are free to
select directors who prioritize what the membership desires.
Non-members, however, have no voice in the proceedings.
73,
Paul, N8HM
On Sun, Jul 20, 2014 at 1:19 PM, John Becker <w0jab@xxxxxxxxx.xxx> wrote:
>
> On 7/20/2014 12:00 PM, Paul Stoetzer wrote: IN PART
>
>> The bottom line is that AMSAT-NA needs a significant boost in
>> membership and visibility and that boost needs to be soon.
>
> I gave up on AMSAT when it seemed that the main afford was put into
> FM in and FM out satellites. Membership ran out many (15) years ago.
>
> John
>
> _______________________________________________
> 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: 4
Date: Sun, 20 Jul 2014 14:16:13 -0400
From: Paul Stoetzer <n8hm@xxxx.xxx>
To: amsat-bb@xxxxxx.xxx
Cc: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] WD9EWK from FN56 starting @ 1727 UTC today...
Message-ID:
<CABzOSOoOnRqdEXuMdMdwVggw17kRG-rHwyDw5JQD0ZgoZ+7fzA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
AC0RA tells me that he worked both Patrick in FN56 and F6CTW on the
1727 UTC AO-7 pass using just 5 watts from an FT-817 and a half Arrow
(4 of the 7 70cm elements) for his uplink.
Maximum elevation of the pass for AC0RA was just 2 degrees.
It doesn't take much power or even antenna to get into the satellites!
The lesson here is to concentrate your efforts on improving your
receive setup!
73,
Paul, N8HM
On Sun, Jul 20, 2014 at 10:53 AM, Patrick STODDARD (WD9EWK/VA7EWK)
<amsat-bb@xxxxxx.xxx> wrote:
> Hi!
>
> I plan on working several passes from grid FN56 in Maine, starting with
the AO-7 pass at 1727 UTC. After a couple of hours up there, I will head
back towards southern Maine or New Hampshire for the night. Hope to work
lots of stations, including some in Europe.
>
> Time permitting, and depending on the local scenery, I might park on the
FN56/FN66 boundary. Otherwise, I will be firmly in FN56.
>
> 73!
>
>
>
>
> Patrick WD9EWK/VA7EWK - Bangor, Maine
> http://www.wd9ewk.net/
>
>
>
>
> _______________________________________________
> 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: 5
Date: Sun, 20 Jul 2014 14:16:29 -0400
From: "Bill \(W1PA\)" <w1pa@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] WD9EWK from FN56 starting @ 1727 UTC today...
Message-ID: <BAY179-DS8AFEA6F53E4F002A3B76A98F30@xxx.xxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Patrick,
Thank you for the eye-ball at the ARRL Convention, and the
new grid today on SO-50.
Congrats to Drew (KO4MA) for his last grid east of the
Mississippi (same pass -- at least that's what I heard).
Bill W1PA
------------------------------
Message: 6
Date: Sun, 20 Jul 2014 14:22:01 -0400
From: "Andrew Glasbrenner" <glasbrenner@xxxxxxxxxx.xxx>
To: "'Bill \(W1PA\)'" <w1pa@xxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] WD9EWK from FN56 starting @ 1727 UTC today...
Message-ID: <04f101cfa447$80485110$80d8f330$@xxx>
Content-Type: text/plain; charset="us-ascii"
Yes!!! Great job from Patrick making that run up there after a full weekend
of AMSAT work at the ARRL Centennial. The man walks the walk!
Pending two cards that are in the mail from a sure-thing QSLer, FN56 will be
the last US grid east of the Rockies for me! I just updated my confirmed
grid map on my QRZ page, and DM57 is the easternmost US grid I need still.
If anyone is in any of those empty grids on that map, I'd love to make a
schedule!
73, Drew KO4MA
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bill (W1PA)
Sent: Sunday, July 20, 2014 2:16 PM
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] WD9EWK from FN56 starting @ 1727 UTC today...
Patrick,
Thank you for the eye-ball at the ARRL Convention, and the new grid today on
SO-50.
Congrats to Drew (KO4MA) for his last grid east of the Mississippi (same
pass -- at least that's what I heard).
Bill W1PA
_______________________________________________
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: 7
Date: Sun, 20 Jul 2014 13:31:25 -0500
From: Clayton Coleman <kayakfishtx@xxxxx.xxx>
To: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
Message-ID:
<CAPovOwckCwvNheW3i+gQOdxruZdNBs8uR2egpGwiUdU1LtxYWw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
This is great news.
I thank all the AMSAT volunteers, past and present for this opportunity.
GO FOX, GO!
73
Clayton
W5PFG
On Jul 18, 2014 2:11 PM, "Joseph Spier" <wao@xxx.xxx> wrote:
> AMSAT NEWS SERVICE
> ANS-199
>
> The AMSAT News Service bulletins are a free, weekly news and infor-
> mation service of AMSAT North America, The Radio Amateur Satellite
> Corporation. ANS publishes news related to Amateur Radio in Space
> including reports on the activities of a worldwide group of Amateur
> Radio operators who share an active interest in designing, building,
> launching and communicating through analog and digital Amateur Radio
> satellites.
>
> The news feed on http://www.amsat.org publishes news of Amateur
> Radio in Space as soon as our volunteers can post it.
>
> Please send any amateur satellite news or reports to:
> ans-editor at amsat.org.
>
> In this edition:
>
> * AMSAT Fox-1C Launch Opportunity Announced
>
> SB SAT @ AMSAT $ANS-199.01
> ANS-199 AMSAT News Service Special Bulletin
>
> AMSAT News Service Bulletin 199.01
> >From AMSAT HQ KENSINGTON, MD.
> DATE July 18, 2014
> To All RADIO AMATEURS
> BID: $ANS-199.01
>
>
> ---------------------------------------------------------------------
>
>
> AMSAT Fox-1C Launch Opportunity Announced
>
>
> AMSAT is excited to announce a launch opportunity for the Fox-1C
> Cubesat. AMSAT has teamed with Spaceflight Inc. for integration and
> launch utilizing Spaceflight's SHERPA system to a sun-synchronous
> orbit in the third quarter of 2015.
>
> Fox-1C is the third of four Fox-1 series satellites under
> development, with Fox-1A and RadFXsat/Fox-1B launching through the
> NASA ELANA program. Fox-1C will carry an FM repeater system for
> amateur radio for use by radio hams and listeners worldwide. Further
> details on the satellite and launch will be made available as soon
> as released.
>
> AMSAT has an immediate need to raise funds to cover both the launch
> contract and additional materials for construction and testing for
> Fox-1C. We have set a fundraising goal of $125,000 dollars to cover
> these expenses over the next 12 months, and allow us to continue to
> keep amateur radio in space.
>
> Donations may be made through the AMSAT webpage at www.amsat.org, by
> calling (888) 322-6728 or by mail to the AMSAT office at 10605
> Concord Street, Kensington, MD 20895, USA.
>
> Please consider a recurring, club, or corporate donation to maximize
> our chance of success with this mission. Also watch our website at
> www.amsat.org,follow us on Twitter at "AMSAT", or on Facebook as
> "The Radio Amateur Satellite Corporation" for continuing news and
> opportunities for support. AMSAT is a 501(c)3 non-profit corporation
> and donations may be tax-deductible.
>
>
>
> [ANS Thanks AMSAT Board of Directors for the above information]
>
>
> ---------------------------------------------------------------------
>
>
> /EX
>
> In addition to regular membership, AMSAT offers membership in the
> President's Club. Members of the President's Club, as sustaining
> donors to AMSAT Project Funds, will be eligible to receive addi-
> tional benefits. Application forms are available from the AMSAT
> Office.
>
> Primary and secondary school students are eligible for membership
> at one-half the standard yearly rate. Post-secondary school students
> enrolled in at least half time status shall be eligible for the stu-
> dent rate for a maximum of 6 post-secondary years in this status.
> Contact Martha at the AMSAT Office for additional student membership
> information.
>
> 73,
> This week's ANS Editor,
> Joe Spier, K6WAO
> k6wao at amsat dot org
>
> _______________________________________________
> 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: 8
Date: Sun, 20 Jul 2014 16:52:28 -0500
From: "Tom Schuessler" <tjschuessler@xxxxxxx.xxx>
To: "'AmsatBB'" <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin
-AMSAT Fox-1C Launch Opportunity Announced
Message-ID: <035a01cfa464$e6231f20$b2695d60$@xxx>
Content-Type: text/plain; charset=US-ASCII
I personally am going to ask my local Amateur Radio Club to throw a donation
on the Fox 1C project. I challenge you to present the same request along to
your own local clubs.
I do numerous Radio Merit Badge presentations for the Boy Scouts and one of
the things I love to do is to throw in a satellite contact opportunity. Yes
linear passes are fun and very capable, but the concept of showing them that
this kind of technology is available and doable with just a simple hand held
radio and an antenna that you can hold in your hand is much more in the
realm of "I could do this too if I had an Amateur Radio license" feeling.
Right now, we only one FM bird up there that can be counted on, SO-50, Fox
1A and 1B are still a year off. (Lituanicasat-1 will be decaying within
days, and maybe two if the French FM satellite opens up soon). Thus the
opportunities for these basic but, Oh for the Scouts, downright exciting
communication events is quite limited. The AO-27 contact we did in one of
those Radio Merit Badge workshops (Before it died), sealed the deal for a
Scout and his dad who were attending and they both ended up getting their
tickets. You can wow them with big ticket equipment and complexity (Smoke
and mirrors), but fun and excitement will get them hooked. Often times,
simple is better.
An additional challenge for the HEO, MEO and Linear or nothing folks out
there is, instead of buying the next accessory for your already ample
station, give a donation to the FOX project (Or other national AMSAT-esque
project, FM, Linear or Digital), and let's get the ball rolling on many new
opportunities out there just waiting. You donation may help get another
Scout/young person hooked on our aspect of the hobby.
Tom Schuessler, N5HYP
------------------------------
Message: 9
Date: Sun, 20 Jul 2014 17:36:44 -0500
From: Alan <wa4sca@xxxxx.xxx>
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>, "SAREX-BB" <SAREX@xxxxx.xxx>
Subject: [amsat-bb] Important information concerning the AMSAT-NA
ballot package
Message-ID: <CBF42CB343644F7682337CD5B4DC8F31@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
AMSAT-NA Members:
After the 2014 AMSAT-NA Board of Directors election ballots were mailed, we
were notified by our
printer that old stock return envelopes were inadvertently included. These
have the old Silver
Spring, MD address. The ballot postcard and other documents have the
correct Kensington, MD address.
Mail is being efficiently forwarded to the new AMSAT-NA office address, and
will continue to be
forwarded for several months. You may use either the envelope included in
the packet, or your own
envelope or address label to send the ballot to the current address:
AMSAT
The Radio Amateur Satellite Corporation
10605 Concord Street
Kensington, MD 20895
USA
We and our printer regret any inconvenience. Whichever method you chose,
please return them promptly
to ensure that your ballot is received by 15 September!
Alan Biddle
WA4SCA
AMSAT Corporate Secretary
------------------------------
Message: 10
Date: Sun, 20 Jul 2014 19:26:02 -0400
From: "Rich/wa4bue" <richard.siff@xxxxxxx.xxx>
To: "'AmsatBB'" <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] What to do and how to do it?
Message-ID: <6363F019F10345B2A4E1E4A05BF774DE@xxxxxxxxx>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
Okay,
This is pretty much the same discussion we use to have at the AMSAT meetings
at Godard in the 1980s.
The problem is and always will be resources (man power and money)
More technology vs the average user. And now who is the average user - the
low cost FMers or the Linear Transponder guys?
Is awful we do not have more useable pass time. Most of the time for our
K4AMG mentoring and demos at schools and special events passes are not
there. This is the nature of the technology we possess.
Is there a strategic plan of how to get from where we are to where we want
to go to best satisfy what we all want?
Until then we have what we have. It seems like everyone needs to chip in
and a more.
Operating the birds as W1AW/4 VA there were several passes that gave great
returns but no one was there on the linear transponders, but all but one FM
pass yielded no contacts.
Turn this discussion into a plan is the answer, not talk but action!
Rich W4BUE
Pres K4AMG
----- Original Message -----
From: "Tom Schuessler" <tjschuessler@xxxxxxx.xxx>
To: "'AmsatBB'" <amsat-bb@xxxxx.xxx>
Sent: Sunday, July 20, 2014 5:52 PM
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -AMSAT
Fox-1C Launch Opportunity Announced
>I personally am going to ask my local Amateur Radio Club to throw a
>donation
> on the Fox 1C project. I challenge you to present the same request along
> to
> your own local clubs.
>
> I do numerous Radio Merit Badge presentations for the Boy Scouts and one
> of
> the things I love to do is to throw in a satellite contact opportunity.
> Yes
> linear passes are fun and very capable, but the concept of showing them
> that
> this kind of technology is available and doable with just a simple hand
> held
> radio and an antenna that you can hold in your hand is much more in the
> realm of "I could do this too if I had an Amateur Radio license" feeling.
>
> Right now, we only one FM bird up there that can be counted on, SO-50, Fox
> 1A and 1B are still a year off. (Lituanicasat-1 will be decaying within
> days, and maybe two if the French FM satellite opens up soon). Thus the
> opportunities for these basic but, Oh for the Scouts, downright exciting
> communication events is quite limited. The AO-27 contact we did in one of
> those Radio Merit Badge workshops (Before it died), sealed the deal for a
> Scout and his dad who were attending and they both ended up getting their
> tickets. You can wow them with big ticket equipment and complexity (Smoke
> and mirrors), but fun and excitement will get them hooked. Often times,
> simple is better.
>
> An additional challenge for the HEO, MEO and Linear or nothing folks out
> there is, instead of buying the next accessory for your already ample
> station, give a donation to the FOX project (Or other national AMSAT-esque
> project, FM, Linear or Digital), and let's get the ball rolling on many
> new
> opportunities out there just waiting. You donation may help get another
> Scout/young person hooked on our aspect of the hobby.
>
>
> Tom Schuessler, N5HYP
>
>
>
> _______________________________________________
> 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: 11
Date: Sun, 20 Jul 2014 16:35:25 -0700
From: Phil Karn <karn@xxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] going digital
Message-ID: <53CC523D.6020801@xxxx.xxx>
Content-Type: text/plain; charset=windows-1252
On 07/20/2014 03:45 AM, John / NS1Z wrote:
> Is there some reason why a digital signal cannot be passed thru an
> analog/linear transponder? What goes in is what comes out. It seems the
> lack of transponder bandwidth limits the digital signal experimenter...
> Maybe that is why commercial transponders on satellites are linear. They
> can take any modulation and retransmit it : AM, FM, PM or CB
You certainly can, and as you point out there are a lot of commercial
satellite transponders that do just that. But the most common practice
there is to drive the transponder power amplifier into nonlinear
saturation to increase its efficiency, and that limits you to a single
signal at a time.
Some transponders are shared among multiple simultaneous ground
transmitters, and to avoid intermodulation distortion they have to back
off on their uplink powers to keep the transponder linear. So besides
having to divide the transponder power by N users, the transponder
converts DC to RF much less efficiently.
Linear power amplifiers are inherently much less efficient than
nonlinear (constant envelope) amplifiers. AMSAT (specifically AMSAT-DL)
has done quite a bit of work to increase linear amplifier efficiency,
but the techniques tend to be inherently limited in bandwidth (a few
hundred kHz max). Much wider bandwidths are available at microwave, and
since the link budgets in LEO support them we'd like to use them.
The transponder also repeats a certain amount of uplink noise, though in
LEO it isn't hard to saturate the uplink receiver so this isn't much of
a factor. But again you tend to be limited to a single user at a time.
So there are considerable advantages to making the satellite itself
digital. It can emit a digital modulation designed to be maximally power
efficient, and it can do so continuously and at full power (solar panels
and batteries permitting). This makes it easy to acquire and track at
the ground station.
Spacecraft power efficiency is our prime consideration, as it determines
the size and cost of the satellite and the required size of the ground
station antenna. And we're trying to minimize that to make our satellite
appeal to many more hams.
Multiuser satellite uplinks and downlinks are fundamentally different
problems, and in a digital satellite with onboard processing the uplink
can easily use a different modulation optimized for the problem. There
are several good options: FDMA as in the PACSATs, CDMA (spread
spectrum), and TDMA. You can even use more than one in combination,
e.g., FDMA or TDMA for the continuous high volume users and CDMA for the
intermittent low volume users. The user data streams can be easily
multiplexed onto the single downlink stream along with data generated
within the satellite itself, such as telemetry, camera images and
scientific instruments, or stored for later transmission over a
different part of the earth.
--Phil
------------------------------
Message: 12
Date: Sun, 20 Jul 2014 19:39:37 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat bb <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
Message-ID:
<CALdCfNLm5zUj2v5aFHP1Eb4_F0PgEE072LY4N2kvL_6xmp0b4Q@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Yes, that is exactly the temperatures of PCSAT in similar eclipse periods.
IE, anything more or less uniformly BLACK (solar panels) no matter the
shape and size will assume that average temperature with 35% eclipses.
This is because the absorbtivity and emissivity of "black" are both 0.9.
(assuming there is some thermal communication within the spacecraft to move
the heat evenly (such as an aluminum frame)...
If it ever gets into a 0% eclipse period (full sun) those average temps
will rise to about 30-40C. Still safe for most electronics.
Bob, WB4APR
On Sun, Jul 20, 2014 at 11:09 AM, Graham Shirville <
g.shirville@xxxxxxxxxx.xxx> wrote:
> Hi Phil,
>
> The reality is, even with no battery heater on FUNcube-1 we seem to have
> an acceptable battery temperature of between 0 and +5C. The temp sensor is,
> of course, actually external to the battery itself.
>
> Our orbit is sun synchronous so we "suffer" eclipses for approx 33% of the
> orbit ..but then we are relatively close to the earth!
>
> I would also comment that any active attitude control system will consume
> power...which we don't have much of..
>
> Probably, if you need continuous operation of the radio system, then a 2U
> with deployable solar panels is the minimum configuration for a CubeSat
> operating on microwave bands with an active attitude control system.
>
> best 73
>
> Graham
> G3VZV
>
>
> -----Original Message----- From: g0mrf@xxx.xxx
> Sent: Sunday, July 20, 2014 3:41 PM
> To: karn@xxxx.xxx ; amsat-bb@xxxxx.xxx ; bruninga@xxxx.xxx
> Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
> AMSAT Fox-1C Launch Opportunity Announced
>
>
> I must quickly point out some real data:
>
> www.warehouse.funcube.org.uk
>
> Which shows an equilibrium of around +20 degrees after 64 minutes of
> sunlight.
> Black solar cells on a black surface but some polished Aluminium in the
> structure.
>
> During eclipse, The Earth facing side begins to increase in temperature at
> around -16 degrees, but then cools down rapidly as the cube rotates. The
> temperature is still heading down rapidly as it exits eclipse after 34
> minutes and at around -24C on the outside surfaces.
>
> Thanks
>
> David
>
>
> -----Original Message-----
> From: Phil Karn <karn@xxxx.xxx>
> To: amsat-bb <amsat-bb@xxxxx.xxx>
> Sent: Sun, 20 Jul 2014 11:59
> Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
> AMSAT Fox-1C Launch Opportunity Announced
>
>
> On 07/19/2014 09:23 PM, Robert Bruninga wrote:
>
> I cannot believe that. The equilibrium of a nominally black (solar panels
>> on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a
>> very benign operational range. The only time you DO have thermal issues
>> is
>> when you DO have attitude control and have things that are not equally
>> over
>> time seeing the sun and dark sky.
>>
>
> See Dick's paper for the details; I'm just quoting his results. I know
> the basic physics of heat transfer in space but I would never call
> myself an expert. He is.
>
> But I can do a back-of-the-envelope calculation that tells me he's right.
>
> The solar cells they're using have an absorptivity and emissivity that
> is both 0.98, as I recall, so a cubesat covered with them is essentially
> a perfect blackbody.
>
> A blackbody cube with one face normal to the sun at 1 AU will reach an
> equilibrium temperature of -21.35 C. The problem is that the ratio of
> radiating area to absorbing area for a cube is 6:1 (with the sun normal
> to one surface). A sphere would be warmer because its ratio of radiating
> to absorbing area is only 4:1. A thin flat plate normal to the sun (like
> a solar wing) would be even warmer -- 2:1.
>
> And that -21.35 C figure is for continuous sunlight. Throw in eclipses
> and things get much worse. Yes, it would be a little better when the sun
> shines on a corner rather than normal to a face, and Earth albedo and IR
> radiation will warm things a little, but not enough to matter.
>
> --Phil
>
> PS: Temperature of 10 cm blackbody cube at 1 AU:
>
> Area facing sun: .01 m^2
> Solar constant: 1367.5 W/m^2
> Absorbed power = 13.675 W
>
> Total radiating area: .06 m^2
> Emissivity = 1.0 (perfect blackbody)
> Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4)
>
>
> T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4)
> = 251.8K == -21.35 C
> _______________________________________________
> 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!
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>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
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>
------------------------------
Message: 13
Date: Sun, 20 Jul 2014 19:45:21 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat bb <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
Message-ID:
<CALdCfNLVBvZ2UoU9=coMXsjza8s1vjK8TqeXKW=Zf3Aw6m_vWA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Thanks for the FOX-1 thermal data! (36 C variation per orbit)
PCSAT (10" cubesat) has less than 15C variation on its sides with its 0.6
RPM spin and 35% eclipses, but this is because the sides are made of 1/8"
aluminum and have a huge 1/8" center deck that is thermally connected to
the center of each face, providing great communication from the sun side to
the other sides. Notice, this was a HEAVY satellite because we just
overbuilt it to make sure the heat was evenly distributed.
On Sun, Jul 20, 2014 at 10:41 AM, <g0mrf@xxx.xxx> wrote:
> I must quickly point out some real data:
>
> www.warehouse.funcube.org.uk
>
> Which shows an equilibrium of around +20 degrees after 64 minutes of
> sunlight.
> Black solar cells on a black surface but some polished Aluminium in the
> structure.
>
> During eclipse, The Earth facing side begins to increase in temperature at
> around -16 degrees, but then cools down rapidly as the cube rotates. The
> temperature is still heading down rapidly as it exits eclipse after 34
> minutes and at around -24C on the outside surfaces.
>
> Thanks
>
> David
>
>
> -----Original Message-----
> From: Phil Karn <karn@xxxx.xxx>
> To: amsat-bb <amsat-bb@xxxxx.xxx>
> Sent: Sun, 20 Jul 2014 11:59
> Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
> AMSAT Fox-1C Launch Opportunity Announced
>
> On 07/19/2014 09:23 PM, Robert Bruninga wrote:
>
> > I cannot believe that. The equilibrium of a nominally black (solar panels
> > on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a
> > very benign operational range. The only time you DO have thermal issues
is
> > when you DO have attitude control and have things that are not equally
over
> > time seeing the sun and dark sky.
>
> See Dick's paper for the details; I'm just quoting his results. I know
> the basic physics of heat transfer in space but I would never call
> myself an expert. He is.
>
> But I can do a back-of-the-envelope calculation that tells me he's right.
>
> The solar cells they're using have an absorptivity and emissivity that
> is both 0.98, as I recall, so a cubesat covered with them is essentially
> a perfect blackbody.
>
> A blackbody cube with one face normal to the sun at 1 AU will reach an
> equilibrium temperature of -21.35 C. The problem is that the ratio of
> radiating area to absorbing area for a cube is 6:1 (with the sun normal
> to one surface). A sphere would be warmer because its ratio of radiating
> to absorbing area is only 4:1. A thin flat plate normal to the sun (like
> a solar wing) would be even warmer -- 2:1.
>
> And that -21.35 C figure is for continuous sunlight. Throw in eclipses
> and things get much worse. Yes, it would be a little better when the sun
> shines on a corner rather than normal to a face, and Earth albedo and IR
> radiation will warm things a little, but not enough to matter.
>
> --Phil
>
> PS: Temperature of 10 cm blackbody cube at 1 AU:
>
> Area facing sun: .01 m^2
> Solar constant: 1367.5 W/m^2
> Absorbed power = 13.675 W
>
> Total radiating area: .06 m^2
> Emissivity = 1.0 (perfect blackbody)
> Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4)
>
>
> T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4)
> = 251.8K == -21.35 C
> _______________________________________________
> 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 9, Issue 242
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