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CX2SA > SATDIG 12.08.08 02:00l 856 Lines 31925 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: DO-64 observation (Bob Bruninga )
2. Transcontinental from Scotland (+ spam troubles)
(John Mock KD6PAG)
3. Re: [eu-amsat] AMSAT UK P3E Lecture Available (John B. Stephensen)
4. Re: DO-64 observation (Luc Leblanc)
5. Re: AMSAT HEO design evolution (longish) (Luc Leblanc)
6. SSB Preamp (Peter)
7. Re: DO-64 observation over ZL (Alan Cresswell)
8. Re: AMSAT HEO design evolution (longish) (SV1BSX)
9. way of satellite recovery? (AB2VY)
10. Re: AMSAT HEO design evolution (longish) (Graham Shirville)
11. Re: way of satellite recovery? (Trevor)
12. DO-64 (WILLIAMS MICHAEL)
13. Re: AMSAT HEO design evolution (longish) (Tony Langdon)
----------------------------------------------------------------------
Message: 1
Date: Mon, 11 Aug 2008 15:10:59 -0400 (EDT)
From: "Bob Bruninga " <bruninga(AT)usna.edu>
Subject: [amsat-bb] Re: DO-64 observation
To: Rick Mann <rmann(AT)latencyzero.com>, wouter weggelaar
<wouterweg(AT)gmail.com>
Cc: amsat Org <amsat-bb(AT)amsat.org>
Message-ID: <20080811151059.AGP10918(AT)mp3.nettest.usna.edu>
Content-Type: text/plain; charset=us-ascii
> As Delfi-C3 goes over the earths poles,
> it flips itself 180 degrees in Z axis
>
> Are you saying it has an active attitude control
> ... Or is the satellite rotating with a period
> equal to that of its orbit?
Actually it is two rotations per orbit. To people on Earth it is "horizontal"
over the equator and vertical over the poles and does a full revolution over
half an orbit.
A benefit is that it prevents any side from facing the sun for more than 12
minutes at a time... and also lets you plan on antenna orientation everywhere.
Bob, WB4APR
------------------------------
Message: 2
Date: Mon, 11 Aug 2008 12:12:48 -0700 (PDT)
From: John Mock KD6PAG <kd6pag(AT)amsat.org>
Subject: [amsat-bb] Transcontinental from Scotland (+ spam troubles)
To: AMSAT-BB(AT)amsat.org
Message-ID: <714144.63439.qm(AT)web34306.mail.mud.yahoo.com>
Content-Type: text/plain; charset=us-ascii
[It appears that my first attempt at posting this failed, perhaps due to
problems i'm having with a spammer using a variant of my e-mail address.]
I'm heading out tomorrow for Scotland. Given the AO-51 schedule, it does
not appear that i'll be able to work very far down the East Coast before i
get to the Shetlands, as the relevant SO-50 passes will be past my bedtime.
I may try to work some continental stations and will post an update if/when
i have Internet access (and something to say). I look forward to working
people from the Shetlands and then from mainland Scotland after the change
to mode J-FM (VU mode). 73's and best of luck!
-- KD6PAG
P.S. Some spammer(s) are forging a variant of my e-mail address and i
had to de-register my home computer's 'fdns.net' address, in the public
interest (e.g. so spam might be rejected more quickly). Please use
'dyndns.org' in place of 'fdns.net', or better yet, use the links from
QSL.net to access my local web resources.
------------------------------
Message: 3
Date: Mon, 11 Aug 2008 17:12:13 -0000
From: "John B. Stephensen" <kd6ozh(AT)comcast.net>
Subject: [amsat-bb] Re: [eu-amsat] AMSAT UK P3E Lecture Available
To: "Joe Westbrook" <k7zt(AT)suddenlink.net>, "Luc Leblanc"
<lucleblanc6(AT)videotron.ca>, <eu-amsat(AT)yahoogroups.com>
Cc: amsat-bb(AT)amsat.org
Message-ID: <00c201c8fbd5$663cde10$0201a8c0(AT)your6bvpxyztoq>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Since AMSAT-DL and AMSAT-NA both require funding from outside the amateur
radio community, are going after different sources of funding, and neither
can predict when they will get that funding, having two efforts would seem
to double the opportunity for a non-LEO satellite.
I don't think that the risk decreases with P3E. 50% of P3 satellites were
lost due to failures of engines in the launch vehicle or in the satellite.
I don't see how having a linear transponder in a geostationary orbit versus
a Molniya orbit makes it an appliance satellite. The antennas and
transceivers on ground are the same in either case.
73,
John
KD6OZH
----- Original Message -----
From: "Joe Westbrook" <k7zt(AT)suddenlink.net>
To: "John B. Stephensen" <kd6ozh(AT)comcast.net>; "Luc Leblanc"
<lucleblanc6(AT)videotron.ca>; <eu-amsat(AT)yahoogroups.com>
Cc: <amsat-bb(AT)amsat.org>
Sent: Sunday, August 10, 2008 16:32 UTC
Subject: [amsat-bb] Re: [eu-amsat] AMSAT UK P3E Lecture Available
> John:
> Yes, you may have heard statements like in the past we've relied on
> charity,
> and Amateur Radio Operators alone can not fund a launch, what you haven't
> heard are any solutions for launching any HEOs. It seems that the DL
> folks
> haven't lost that as a focus, they acknowledge that as expensive as it is
> to
> launch an HEO, it is still doable. 3 - 4M Euros $4 - 5M at least they gave
> us a tangible figure we can work with. This amount may be a reach for
> AMSAT-NA alone, but given that we finally understand what it would take to
> make a HEO Launch reality, then why wouldn't we shift ALL funding toward
> that effort? Following the PE3 launch, if any surplus remains, the
> surplus could be transferred to the next HEO opportunity (Eagle). If no
> surplus remains then at least we would have one working HEO deployed.
>
> Additionally, at least we know the PE3 platform is well vetted, and would
> have the lowest risk. Rather than spending time and resources on a new,
> untested platform why wouldn't we just facilitate PE3 FIRST?
>
> Ok, I'll speech for myself here, but the GEO ride-share simply isn't an
> opportunity that will interest the HEO crowd. Launching an appliance to
> serve the disaster response community and entry level satellite users
> won't
> do a thing to satisfy the need for a HEO. I don't care if it's free, like
> AO51, I would probably get on it, make a couple contacts say "that's nice"
> and be done with it. Please understand, I'm not saying to abandon GEO as
> a
> viable option, just don't spend a cent on it until we launch an HEO.
>
> What we need is a satellite that enables the real sprit and intent of the
> Amateur Radio Service, to push the envelop of the technology, allow for
> experimentation, consider all of the alternative antenna solutions that
> our
> resourceful community developed to receive the 2.4Gig Down Link. No
> rotator
> required, different feed systems, a fairly modest resource outlay to get
> on
> the air. I did it with a totally home brewed system in a restricted
> neighborhood back yard. Had a blast and learned allot.
>
> ----- Original Message -----
> From: "John B. Stephensen" <kd6ozh(AT)comcast.net>
> To: "Luc Leblanc" <lucleblanc6(AT)videotron.ca>; <eu-
amsat(AT)yahoogroups.com>
> Cc: <amsat-bb(AT)amsat.org>
> Sent: Friday, August 08, 2008 3:14 PM
> Subject: [amsat-bb] Re: [eu-amsat] AMSAT UK P3E Lecture Available
>
>
>> I've been hearing these two statments from AMSAT-NA officals for at least
>> 2
>> years -- in person and on this BB.
>>
>> 73,
>>
>> John
>> KD6OZH
>>
>> ----- Original Message -----
>> From: "Luc Leblanc" <lucleblanc6(AT)videotron.ca>
>>>
>>> Very nice presentations. One attract my attention was made by Peter
>>> Guelzow DB2OS one one of his slide we can read:
>>>
>>> ATTRACTIVENESS OF AMATEUR RADIO HAS DROPPED SIGNIFICANTLY
>>>
>>> FUNDING A SATELLITE FROM AMATEUR RESSOURCES ALONE NEVER WORKED BEFORE
>>> AND
>>> WILL NOT WORK NOW.
>>>
>>> I don't how to explain how all the wisdom and reality knowledge seems to
>>> be concentrated in Europe when speaking about amateur satellite?
>>
>> _______________________________________________
>> Sent via AMSAT-BB(AT)amsat.org. 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(AT)amsat.org. 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: Mon, 11 Aug 2008 15:20:07 -0400
From: Luc Leblanc <lucleblanc6(AT)videotron.ca>
Subject: [amsat-bb] Re: DO-64 observation
To: amsat-bb(AT)AMSAT.Org
Cc: eu-amsat(AT)yahoogroups.com
Message-ID: <48A058A7.2620.4661E2(AT)lucleblanc6.videotron.ca>
Content-Type: text/plain; charset=US-ASCII
On 11 Aug 2008 at 15:12, wouter weggelaar wrote:
> Hi Luc,
>
> Thanks for your report here on the BB,
> Did you try to switch your polarization between LHCP and RHCP?
> As Delfi-C3 goes over the earths poles, it flips itself 180 degrees in
> Z axis (perpendicular to earth). Otherwise one side will be always
> exposed to sunlight and things might run hot / degrade in time.
> Due to this flip, the polarization sense changes depending on which
> pass you are tracking (ascending from south to north, or descending
> from north to south)
> If you do not switch polarization sense, you can observe big
> differences between those two.
> Please bear in mind that Delfi does not have any active attitude
> control system and solely relies on passive stabilization.
> During a pass, polarization might change due to slow rotations. You
> could try to switch polarization within a pass and see whichever is
> stronger.
>
> Delfi-C3 does have an RF AGC within the IF-stage, so uplinking more
> power than necessary only limits other weaker stations and does not
> improve your own signal.
>
> We received some reports about people uplinking using a FT817 with
> abt. 5 Watts into an arrow antenna, so your 1 or 2 watts with a good
> antenna could do miracles...;)
> Reports of Delfi-C3 (DO-64) transponder operation are greatly
> appreciated and can be sent to info at delfic3.nl or via the BB.
>
>
> On behalf of the Delfi-C3 team,
>
> Best 73's
>
> Wouter Weggelaar
> PA3WEG
> Delfi-C3 Command Team
>
>
>
>
Thank's Wouter for your comments.
The change in signal strength appears at TCA exactly at west and it was a
southbound pass. I guess the antenna main lobe was directed at me
and when the satelllite passed my TCA point the main lobe was not directed at
me.
Half the pass was very good and the other extremely weak i'm using a 14 elem
cross yagi stuck in right hand polarisation i know a 3DB
difference due to polarisation change on a yagi but much more when using the
wrong polarisation. This old KLM 2M 14C suffer numerous
winters 2 crash down and the relay and the relay board where broken up to a
point of no repair the only one solution is to make two
separate antenna. I someone used to modified on of theses old beam it will be
interesting to know what the impedance is at the end of the 2
4 to 1 balun? It will be nice if it will be 52ohms! But i guess it is 100
ohms as the 2 balun line are tied to a SO-239 connector.?
The audio quality is nearly as good as FO-29 by the way nice sat to experiment
with.
"-"
Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE
------------------------------
Message: 5
Date: Mon, 11 Aug 2008 16:06:14 -0400
From: Luc Leblanc <lucleblanc6(AT)videotron.ca>
Subject: [amsat-bb] Re: AMSAT HEO design evolution (longish)
To: amsat-bb(AT)AMSAT.Org
Cc: eu-amsat(AT)yahoogroups.com
Message-ID: <48A06376.16969.709C7D(AT)lucleblanc6.videotron.ca>
Content-Type: text/plain; charset=US-ASCII
On 11 Aug 2008 at 13:00, G0MRF(AT)aol.com wrote:
>There are probably ways of trimming this back substantially.
> In LEO sat design we have seen a reduction in size from 400kg to the SSTL
> microsat of about 120kg in the 1980's. These days the SSTL 'microsat' has
> evolved down to 3 - 5kg. with projects like the NASA Nanosail design. But
no such
> revolution has taken place in HEO satellites
> So, a few possibilities. You can probably think of more......
>
> Could we do HEO within a 50kg budget? = 1.5million Euros spread over a 10
> year lifespan?
>
If i read you correctly you mean no more bells and whistles only a +- plain
transponder? But if i remember correctly it seems some of the
builders does not found the challenge up to their ambitions!
The new vector now is the human factor and it seems as hard to deal with than
the funding issues!
Remain my Paris Hilton solution and i was wrong she's 27 but still blonde and
cute with a lot of cash. The age factor is further reducing
our funding chances here not speaking for myself naturally and my english is
too bad anyway...
Trivia question:
What was the average attendance age at the last AMSAT-UK symposium
conferences?
Your answer will let you know how soon the next HEO is desirable!
"-"
Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE
------------------------------
Message: 6
Date: Mon, 11 Aug 2008 16:39:56 -0400
From: Peter <roi(AT)optonline.net>
Subject: [amsat-bb] SSB Preamp
To: AMSAT-BB(AT)amsat.org
Message-ID: <007101c8fbf2$ade9d7a0$6701a8c0(AT)peter>
Content-Type: text/plain; charset=Windows-1252
Hi,
Is anyone using a SSB SP-7000 preamp and an Icom 910H powered via direct
feed from the coax. I am not able to turn the preamp on with this method, I
set the menu for the preamp and the front panel; it recognizes a preamp but
it's not working, any ideas?
73 Peter
WB2OQQ
------------------------------
Message: 7
Date: Mon, 11 Aug 2008 21:00:55 -0000
From: "Alan Cresswell" <alancresswell(AT)xtra.co.nz>
Subject: [amsat-bb] Re: DO-64 observation over ZL
To: <amsat-bb(AT)amsat.org>
Message-ID: <000301c8fbf5$59be1d50$0401010a(AT)Dell1>
Content-Type: text/plain; charset="us-ascii"
A few observations from down under.
So far I have had 12 contacts through DO-64, mostly with VK. (With nothing
to work out to the East or North there is no activity on the majority of
passes.) The beacon is consistently strong on all passes and on a few
passes has shown some distortion for about a minute as Delfi approaches 60
deg South. This was also the case in science mode. The transponder signal
is somewhat variable. Some passes have very good downlink signals and some
are apparently weaker. (S.C. orientation presumably.) I have not noticed
much variability throughout a pass - strong downlink passes stay strong and
weaker passes stay weak. In general the beacon is stronger than the
transponder downlink. With no other stations on DO-64, increasing uplink
power from 5 to 10 watts results in an increase in downlink signal. (All
observations using 19 elements on 70cm and 10 elements on 2m with switchable
polarization and Az/El tracking.) All in all an interesting and useful
addition to the satellite options in this part of the world.
Alan
ZL2BX
------------------------------
Message: 8
Date: Tue, 12 Aug 2008 00:06:38 +0300
From: "SV1BSX" <sv1bsx(AT)yahoo.gr>
Subject: [amsat-bb] Re: AMSAT HEO design evolution (longish)
To: <G0MRF(AT)aol.com>, <m5aka(AT)yahoo.co.uk>, <amsat-bb(AT)amsat.org>
Message-ID: <006b01c8fbf6$2839c3a0$0b09a8c0(AT)zeus>
Content-Type: text/plain; format=flowed; charset="windows-1253";
reply-type=original
Hi David, Hi all,
I found your statement very logical and I agree with you. Definitely we must
be more "flexible" in the new era and no "glued". Probably the
"HEO-projects"
like Phase-3 belong to the past century and just... we don't want to accept
it.
The money cost is unbelievable high. Definitely is necessary to re-assign
the
"HEO's concept" according to the currently & future era.
However, in addition to your Email I would like to remind that:
if we can not launch a HEO, why not about a MEO? I remember a nice page
around Internet (unfortunately I can't find this page any longer) where
described the possibility for a MEO OSCAR, by using a small propellant
system onboard in order to be able to put the satellite higher than any LEO.
Thus the launching-cost should be very reasonable - even nowadays.
I don't know if that is possible in practice - I am not an expert about
that! However sounds to me as a great challenge for Ham radio, if a new
kind of Satellite-orbit could be available for Amateur Radio operators
If we can't to put a HEO in orbit, why not a MEO? The footprint is
spectacular vis-a-vis to a LEO.
Not like a HEO, but good enough in order to keep "warm" the Amateur
Satellite
community by offering DX + overseas QSOs.
73, Mak SV1BSX
----- Original Message -----
From: <G0MRF(AT)aol.com>
To: <m5aka(AT)yahoo.co.uk>; <amsat-bb(AT)amsat.org>
Sent: Monday, August 11, 2008 8:00 PM
Subject: [amsat-bb] AMSAT HEO design evolution (longish)
> Given the understandable negative content of the posts recently regarding
> the AMSAT HEO satellite debate, perhaps it's time to return to basics and
> ask
> some fundamental questions about the way we design satellites and fund
> their
> launch.
>
> The problem: AMSAT High Earth Orbiting satellites have historically had
> a
> mass between 150kg for P3 and 650kg+ for AO-40 and at 30,000 Euros per
> kg, we
> do not have the resources to self finance the launch costs of 4.5
> million
> (30k x 150) to 15 million Euros to launch.
> However, AO-40 was probably a 1-off and will never be repeated. So let's
> say
> 4 - 5 million.
>
> The way forward?
> 1) Raising the funds for the standard launch cost of the typical AMSAT HEO
> is beyond us. So other external funding solutions are needed either by
> providing a service which is paid for. - An example of exploring this
> route is the
> AMSAT NA proposed Advanced Communications Project via Intelsat.
> A second approach, is to include commercial payloads within the AMSAT
> spacecraft, or perhaps including AMSAT 'functionality' within other
> commercially or
> educationally funded spacecraft. Again, there are examples of this
> approach
> for LEOs. Delfi C3 is one success story. Also, and had it worked for more
> than a few orbits the ESA Education department / SSETI Express XO-53 was
> another. But at HEO the opportunites are very rare indeed, the only
> project
> currently being persued is the ESA ESEO educational mission with AMSAT UK
> providing
> a U/S transponder as part of a redundant communications system for the
> spacecraft.
> As we have been reminded in the past few days, self funding never worked
> before and it wont work in the future. I feel some sympathy for the AMSAT
> NA
> board who have an apparently impossible task to fulfil, but their
> enthusiasm to
> elicit support has let expectations exceed funding ability. - The response
> ha
> s been vocal. But at least they are trying.
> Finally on the funding issue, what have we done in the last 8 years?
> We've
> had the Eagle fund. We've had the successful AO-51 fund raising campaign,
> but
> really, since the launch of AO-40 in November 2000 we haven't saved for
> this
> 'HEO' eventuality. If we are ever going to replace spacecraft in the
> future,
> fund raising needs to be more sustained and less impulse led. We have
> little
> to show for the last 8 years.
>
>
>
> 2) There is however another option which may be self financing. A
> fundamental spacecraft redesign to reduce the mass to a figure we can
> afford to launch.
> Over the last 25 years, the mass of a P3 spacecraft has remained fairly
> constant. About 90kg of structure and payload with an additional 60kg of
> bi-propellent fuel. There are probably ways of trimming this back
> substantially.
> In LEO sat design we have seen a reduction in size from 400kg to the SSTL
> microsat of about 120kg in the 1980's. These days the SSTL 'microsat' has
> evolved down to 3 - 5kg. with projects like the NASA Nanosail design. But
> no such
> revolution has taken place in HEO satellites
> So, a few possibilities. You can probably think of more......
>
> a) The 60kg of fuel has been needed to raise perigee and increase
> inclination from a typical geostationary transfer orbit. But there have
> been orbital
> change manoeuvres that have not gone to plan e.g. AO-10 and AO-40, but
> those
> satellites have still given us usable communications. Do we need all
> 60kg?
> How about raising the perigee to give a long life and a slight increase
> in
> inclination to get us out of the GTO belt around from around 7 degrees to
> 15
> degrees? I wonder what the saving is there, 400 Newton motor down to 50
> Newton
> motor. Fuel from 60kg down to 15kg? Saving = 45 + 5kg = 1.5 million
> Euros?
> OK the figures are guesswork, but there must be savings.
>
> b) Spacecraft design. During our time with P3 spacecraft, we have seen
> transponder power change dramatically. I recall the first few days of
> AO-40 when I
> heard the 2m beacon stronger than many local FM stations. But then it used
> a
> 300 Watt BLF278 type device and was designed to give a huge signal.
> Equally,
> I also recall receiving a worked all continents satellite award for QSOs
> I
> made on the experimental AO-13 mode S transponder. That was 1 Watt (max)
> into a
> 5 turn helix on 2400. So, in the future, do we need 45 or 50 Watts of
> power
> in a 100kHz wide transponder? After all, if there are fewer amateurs, we
> can
> use less bandwidth saving power and mass in the process. 8 Watts and
> 50kHz? A consequence of such a design change would require a
> groundstation with
> more than a patch antenna to pick up the signal. But is that
> unreasonable,
> dishes are cheaper than launches.
>
> c) Two final thoughts. Firstly, isn't the world moving away from metal
> structures to carbon and ceramic composites. Mass saving perhaps.
> Secondly, I
> don't think AMSAT with it's limited resources can afford to put spacecraft
> into
> orbit that will fail the moment the batteries die. Let's not dwell on the
> excellent Delfi example, but instead look at the Intelsat spacecraft. Is
> it not
> the case that they have a 10 year lifespan which is limited by
> stationkeeping
> fuel? While they operate 24/7 the power comes from the solar cells. The
> batteries are used only in eclipse. With our P3 designs, as I understand
> them,
> the spacecraft can not function on solar cells alone. Unfortunately, the
> advantage of our chosen HEO orbits also mean that the batteries on a P3
> satellite
> go through a couple of eclipses a day. As battery life is proportional
> (or
> worse) to depth of discharge of the batteries, it's not surprising that
> most
> AMSAT spacecraft suffer battery failure. But with limited funds we really
> need
> to design in a mode so that 5 years on, the batteries can be switched out
> of
> circuit and a sensible geometry of solar panels can continue to provide
> some
> daylight only functionality.
>
> Conclusion:
> Funding campaigns need to run over several years within a rolling plan to
> supply launch funding.
> Designs need to evolve to include new technologies. Mass reduction = lower
> launch cost should be near the top of the list.
> With fewer amateurs, and modern digital modes we need less bandwidth.
> It is not unreasonable for an AMSAT member to need a moderate size of
> antenna to work an HEO. So, lower power in space.
> Lifespan needs to be increased and with HEO that means battery failure
> should be anticipated and mitigated in the design. A daylight operating
> spacecraft
> is better than no spacecraft at all.
>
> Thanks..........a quiet day here!
>
> David
>
> Could we do HEO within a 50kg budget? = 1.5million Euros spread over a
> 10
> year lifespan?
>
>
>
>
>
> _______________________________________________
> Sent via AMSAT-BB(AT)amsat.org. 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: 9
Date: Mon, 11 Aug 2008 21:12:22 +0000 (GMT)
From: AB2VY <amprorg(AT)yahoo.it>
Subject: [amsat-bb] way of satellite recovery?
To: AMSAT-BB(AT)amsat.org
Message-ID: <744093.54846.qm(AT)web26505.mail.ukl.yahoo.com>
Content-Type: text/plain; charset=utf-8
Hi to everybody, after have reading this article about the possibility of
bringing Vanguard 1 back to Earth http://www.msnbc.msn.com/id/23639980/ , an
"unhealthy" idea has crossed my brain... , premise that Vanguard 1 is "3.25-
pound (1.5-kilogram), 6.4-inch-wide (16.3-centimeter-wide)" so little.. , a
program to recover/repair something of too bigger ( like... AO40 ?? ......) is
possible ? if the answer is "yes" the costs are too bigger or too low than the
launch costs (4.5 million to 15 million Euros to launch) explained by David
G0MRF in the past message?
Logically it is necessary that NASA has a similar mission to which rely...
would be an interesting study on this possibility of recovery/repair a
satellite like AO40 "dead" in space
this message wants to be an open track for a discussion about "Satellite
repair in Space"
thanks for your attention and best 73
Giulio AB2VY (ex KC2OTB)
c/o Toms River NJ
AMSAT-NA member 36417
Posta, news, sport, oroscopo: tutto in una sola pagina.
Crea l'home page che piace a te!
www.yahoo.it/latuapagina
------------------------------
Message: 10
Date: Mon, 11 Aug 2008 22:29:39 +0100
From: "Graham Shirville" <g.shirville(AT)btinternet.com>
Subject: [amsat-bb] Re: AMSAT HEO design evolution (longish)
To: "SV1BSX" <sv1bsx(AT)yahoo.gr>, <G0MRF(AT)aol.com>, <m5aka(AT)yahoo.co.uk>,
<amsat-bb(AT)amsat.org>
Message-ID: <00a001c8fbf9$5d173690$021410ac(AT)allgood.local>
Content-Type: text/plain; charset="iso-8859-1"
> if we can not launch a HEO, why not about a MEO? I remember a nice page
> around Internet (unfortunately I can't find this page any longer)
Try one of David's own pages:
http://www.g0mrf.freeserve.co.uk/MEOSAT.htm
Really interesting and thought provoking reading!
73
Graham
G3VZV
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Message: 11
Date: Mon, 11 Aug 2008 21:38:42 +0000 (GMT)
From: Trevor <m5aka(AT)yahoo.co.uk>
Subject: [amsat-bb] Re: way of satellite recovery?
To: AMSAT-BB(AT)amsat.org, AB2VY <amprorg(AT)yahoo.it>
Message-ID: <266128.69854.qm(AT)web27202.mail.ukl.yahoo.com>
Content-Type: text/plain; charset=utf-8
Nice idea , however costs make it unfeasable,
Somebody can I'm sure post the costs of the Shuttle Missions that have
recovered/repaired satellites. I suspect each mission cost many tens of
millions of dollars. No unmanned mission has ever retrieved a satellite.
AO-40 is a far higher orbit than Vanguard, so costs of recovery would be far
greater.
73 Trevor M5AKA
--- On Mon, 11/8/08, AB2VY <amprorg(AT)yahoo.it> wrote:
From: AB2VY <amprorg(AT)yahoo.it>
Subject: [amsat-bb] way of satellite recovery?
To: AMSAT-BB(AT)amsat.org
Date: Monday, 11 August, 2008, 10:12 PM
Hi to everybody, after have reading this article about the possibility of
bringing Vanguard 1 back to Earth http://www.msnbc.msn.com/id/23639980/ , an
"unhealthy" idea has crossed my brain... , premise that Vanguard 1 is
"3.25-pound (1.5-kilogram), 6.4-inch-wide (16.3-centimeter-wide)" so
little.. , a program to recover/repair something of too bigger ( like... AO40
??
......) is possible ? if the answer is "yes" the costs are too bigger
or too low than the launch costs (4.5 million to 15 million Euros to launch)
explained by David G0MRF in the past message?
Logically it is necessary that NASA has a similar mission to which rely...
would be an interesting study on this possibility of recovery/repair a
satellite
like AO40 "dead" in space
this message wants to be an open track for a discussion about "Satellite
repair in Space"
thanks for your attention and best 73
Giulio AB2VY (ex KC2OTB)
c/o Toms River NJ
AMSAT-NA member 36417
Send instant messages to your online friends http://uk.messenger.yahoo.com
------------------------------
Message: 12
Date: Mon, 11 Aug 2008 14:44:45 -0700 (PDT)
From: WILLIAMS MICHAEL <k9qho6762(AT)sbcglobal.net>
Subject: [amsat-bb] DO-64
To: amsat-bb(AT)amsat.org
Message-ID: <558301.36267.qm(AT)web82706.mail.mud.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
I did get two good descending passes today at 14:16 and 15:51 UTC.
The 14:16 UTC pass was at 10 degrees maximum elevation and I was able to
hear myself through the transponder satisfactory. My antennas are only 2.4
meters above ground so reception is blocked by buildings and trees. The pass
was good enough for a QSO on CW.
On the 15:51 UTC pass, I could hear the 200 mW transponder from just after
AOS to about 3 degrees from LOS. When Delfi was above the ground objects, I
could reduce my output to 2 watts and still return an excellent signal from
Delfi
Down link antenna is 14 ele. KLM LHCP
Up link antenna is 11 turn helix RHCP
Mike Williams
K9QHO
AMSAT 33589
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Message: 13
Date: Tue, 12 Aug 2008 07:47:51 +1000
From: Tony Langdon <vk3jed(AT)gmail.com>
Subject: [amsat-bb] Re: AMSAT HEO design evolution (longish)
To: G0MRF(AT)aol.com, m5aka(AT)yahoo.co.uk, amsat-bb(AT)amsat.org
Message-ID: <48a0b38e.11bd720a.278e.1803(AT)mx.google.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 03:00 AM 8/12/2008, G0MRF(AT)aol.com wrote:
>How about raising the perigee to give a long life and a slight increase in
>inclination to get us out of the GTO belt around from around 7 degrees to 15
>degrees? I wonder what the saving is there, 400 Newton motor down
>to 50 Newton
>motor. Fuel from 60kg down to 15kg? Saving = 45 + 5kg = 1.5 million Euros?
>OK the figures are guesswork, but there must be savings.
Well, you're not going to get too many arguments from those of us
south of the equator. :-) Inclination change is the most expensive
manouvre, in terms of fuel consumption, so minimising this will
dramatically reduce fuel consumption. Raising perigee, OTOH, is much
less of a drain on fuel reserves.
>5 turn helix on 2400. So, in the future, do we need 45 or 50 Watts of power
>in a 100kHz wide transponder? After all, if there are fewer amateurs, we can
>use less bandwidth saving power and mass in the process. 8 Watts and
>50kHz? A consequence of such a design change would require
>a groundstation with
>more than a patch antenna to pick up the signal. But is that unreasonable,
>dishes are cheaper than launches.
There might be a fly in the ointment here. Many US hams are unable
to erect any outside antennas. Down here, we're a bit more
fortunate. It is true that dishes are cheaper than launches, but one
has to find the "sweet spot". And maybe some of the money saved can
go towards making it easier for newcomers to setup a suitable ground station.
>excellent Delfi example, but instead look at the Intelsat
>spacecraft. Is it not
>the case that they have a 10 year lifespan which is limited by
>stationkeeping
>fuel? While they operate 24/7 the power comes from the solar cells. The
>batteries are used only in eclipse. With our P3 designs, as I
>understand them,
>the spacecraft can not function on solar cells alone. Unfortunately, the
Good idea. And that's where raising the satellite's perigee can have
a big advantage. A higher perigee means fewer eclipses, which
translates to less discharge cycles on the batteries, and longer
periods of solar only operation possible.
If you look carefully, you'll see a series of compromises between
cost, groundstation cost (has to be multiplied by the number of
potential users) and groundstation practicality, coverage and the
ability to run on solar power alone. Where is the sweet spot?
73 de VK3JED
http://vkradio.com
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End of AMSAT-BB Digest, Vol 3, Issue 406
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