July 2024 - AMSAT-BB - mailman.amsat.org

Re: SO-50 Key to Longivity?
by Bruce Perens 22 Jul '24

22 Jul '24

> And what have we learned from IO-117 about radiation resistance, etc? Perhaps one of us has access to the full paper, here's the abstract: https://iris.uniroma1.it/handle/11573/1703313 Insist on Diamond Open Access for your scholarly publications. That is a journal that does not charge either authors or readers. On Mon, Jul 22, 2024 at 9:45 AM JOHN GEIGER via AMSAT-BB <amsat-bb(a)amsat.org> wrote: > Unfortunately I don't know much about IO-117 so that is a question I can't > answer. > > 73 John AF5CC > > Sent using Zoho Mail > > > > ---- On Mon, 22 Jul 2024 11:31:20 -0500 * <crohtun(a)aim.com > <crohtun(a)aim.com>>* wrote --- > > And what have we learned from IO-117 about radiation resistance, etc? > > Ray Crafton KN2K > > > Sent from the all new AOL app for iOS > <https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661> > > On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB < > amsat-bb(a)amsat.org> wrote: > > > SO-50 will be 22 years old in December and seems to be still be going > strong, in sunlight and in eclipse. No other satellite launched since then > has lived near that long. So what is SO-50s key to long life? Is it how > the satellite was built? Something in its operation, like lower power on > transmit? Its orbital setup? > > Any ideas why it has lived so much longer than the recent crop of AMSATS? > > 73 John AF5CC > > Sent using Zoho Mail > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org -- Bruce Perens K6BP

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Re: SO-50 Key to Longivity?
by Will Ruef 22 Jul '24

22 Jul '24

Jim, Thanks for providing this info. Very interesting read. Do you know of any hi-res images taken of SO-50 before it was launched? I have always been kind of curious what the bird looks like. There are a few sites with images of it but 3 or 4 of them have conflicting images of obviously different cube sats. Thanks for being a part of building such a great FM sat. I can't even imagine the amount of amateurs that have had fun working SO-50 over the years. 73, Will KN6QVA On 7/22/24 3:39 PM, Jim White via AMSAT-BB wrote: > > Managing the battery discharge by adjusting current draws - by turning > things on/off or changing the power level of the transmitter, has been > done since the 1990 AMSAT Microsats (or the SSTL birds before them). > At least we did that in one the ones I worked on. I think it's still > true that the most common cause of satellite failure is batteries > doing bad, and the one's I'm familiar with were because the batteries > got pulled down to the resting voltage (about 1V/cell for NiCads). > They will reverse polarity or short when you mistreat them. With > chemistries like LiPoly, if you mistreat them they just die, or explode. > > You prevent that by making sure you never pull the voltage too low, > and by not overcharging them. Another feature in the Microsats was to > reduce battery charging when they got near "full" by moving the solar > panel off the optimum point in the I/V curve. I have seen many > examples of missions that sat on the shelf for months with the battery > (whatever chemistry) discharging. Then at separation they turn on a > bunch of stuff and, drew the batteries into the ditch, reset, and > maybe came back on. And a few that did that over and over until > operators managed to stop it by command. Or they died. > > In the Microsats, and others I worked on, we took a very conservative > approach. At sep, turn on only what is absolutely needed, beacon at a > slow rate and lower power, let the batteries charge up and let the > operators decide when to turn on the ACS or other stuff - after being > sure there was enough power available. > > So to the extent batteries are managed properly as in Falconsat 3 and > SO50, yes, that definitely extends the life. > > Having said that if you design goal is a year of operation at higher > TX power with a full ACS running, or gathering a lot of science data, > you accept the satellite life will be shorter. > > It's all a trade-off. Actually, many trade-offs all tangled up with > each other. > > Jim > > > On 7/22/2024 4:17 PM, Brian Wilkins via AMSAT-BB wrote: >> Jim >> >> Did the TX timer help to extend the life of the satellite? >> >> 73, ko4aqf(a)gmail.com >> >> >> On Mon, Jul 22, 2024 at 1:17 PM Jim White via AMSAT-BB >> <amsat-bb(a)amsat.org> wrote: >> >> I'll provide a bit of input here since I worked on SO50. Here >> are some considerations. >> >> - The hardware was mostly built by SpaceQuest and used proven >> designs that had been flown several times >> >> - The design goal was long life. The orbits would provide that, >> unlike some current launches were the orbit will last a shorter >> time. The idea was to provide a long life resource for all to use. >> >> - The software followed proven designs dating back to the 1990 >> Microsats. All software except the boot loader (in rad protected >> RAM) was uploadeable. The SCOS real-time operating system >> allowed individual tasks to be killed and uploaded without >> disturbing other tasks or the OS. SCOS was quite robust. >> >> - There were no I2C busses to latch up, and no flash cards (both >> of which cause problems in current designs) >> >> - The program memory was rad hard, the OS 'washed' that memory >> every 10 minutes to eliminate bit flips from passing through the >> SAA. The data memory used Huffman software rad recovery. >> >> - Antennas we not deploy-able and were made of piano wire so were >> quite robust. >> >> - The batteries were NiCAD so were robust and hard to hurt. They >> work fine over a wide temperature range and don't need heaters. >> Don't need to manage charging as carefully and don't need to be >> concerned about not charging if outside a temp range. >> >> - The software automatically adjusted TX power output to prevent >> pulling the battery V too low and causing a reset. There were >> three steps of battery management, each turning off more stuff to >> reduce load and attempt to prevent full discharge. >> >> - Batteries were very carefully matched using the process first >> developed for the Microsats. >> >> - The power system included adjusting the solar panel input >> impedance to constantly maximize power from the panels. And >> another algorithm prevented overcharging. A manual process is >> used to adjust those algorithms as the battery capacity drops >> with time and the panels loose efficiency. >> >> - The software kept the dept of discharge of the batteries to no >> more than about 20%, resulting in much longer battery life. >> >> Jim, WD0E >> >> >> On 7/22/2024 10:46 AM, JOHN GEIGER via AMSAT-BB wrote: >>> Unfortunately I don't know much about IO-117 so that is a >>> question I can't answer. >>> >>> 73 John AF5CC >>> >>> Sent using Zoho Mail >>> >>> >>> >>> >>> ---- On Mon, 22 Jul 2024 11:31:20 -0500 *<crohtun(a)aim.com> >>> <mailto:crohtun@aim.com>* wrote --- >>> >>> And what have we learned from IO-117 about radiation >>> resistance, etc? >>> >>> Ray Crafton KN2K >>> >>> >>> Sent from the all new AOL app for iOS >>> <https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661> >>> >>> On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB >>> <amsat-bb(a)amsat.org> wrote: >>> >>> >>> SO-50 will be 22 years old in December and seems to be >>> still be going strong, in sunlight and in eclipse. No >>> other satellite launched since then has lived near that >>> long. So what is SO-50s key to long life? Is it how >>> the satellite was built? Something in its operation, >>> like lower power on transmit? Its orbital setup? >>> >>> Any ideas why it has lived so much longer than the >>> recent crop of AMSATS? >>> >>> 73 John AF5CC >>> >>> Sent using Zoho Mail >>> >>> >>> >>> >>> ----------------------------------------------------------- >>> >>> Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. >>> AMSAT-NA makes this open forum available >>> to all interested persons worldwide without requiring >>> membership. Opinions expressed >>> are solely those of the author, and do not reflect the >>> official views of AMSAT-NA. >>> Acceptable Use and Privacy Policies available at >>> https://www.amsat.org/about-amsat/ >>> >>> View archives of this mailing list at >>> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >>> To unsubscribe send an email to >>> amsat-bb-leave(a)amsat.org <http://amsat.org> >>> Manage all of your AMSAT-NA mailing list preferences at >>> https://mailman.amsat.org >>> >>> >>> >>> >>> >>> ----------------------------------------------------------- >>> >>> Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes this open forum available >>> to all interested persons worldwide without requiring membership. Opinions expressed >>> are solely those of the author, and do not reflect the official views of AMSAT-NA. >>> Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ >>> >>> View archives of this mailing list at >>> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >>> To unsubscribe send an email to amsat-bb-leave(a)amsat.org <http://amsat.org> >>> Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org >> >> ----------------------------------------------------------- >> >> Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes >> this open forum available >> to all interested persons worldwide without requiring membership. >> Opinions expressed >> are solely those of the author, and do not reflect the official >> views of AMSAT-NA. >> Acceptable Use and Privacy Policies available at >> https://www.amsat.org/about-amsat/ >> >> View archives of this mailing list at >> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >> To unsubscribe send an email to amsat-bb-leave(a)amsat.org >> <http://amsat.org> >> Manage all of your AMSAT-NA mailing list preferences at >> https://mailman.amsat.org >> >> >> ----------------------------------------------------------- >> >> Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available >> to all interested persons worldwide without requiring membership. Opinions expressed >> are solely those of the author, and do not reflect the official views of AMSAT-NA. >> Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ >> >> View archives of this mailing list at >> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >> To unsubscribe send an email to amsat-bb-leave(a)amsat.org >> Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org

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Re: SO-50 Key to Longivity?
by Bruce Perens 22 Jul '24

22 Jul '24

Supercapacitor lifetime: https://abracon.com/uploads/resources/Supercapacitor-Lifetime-Explained.pdf There seem to be a lot of papers on space-qualified supercapacitors, but no off-the-shelf space-qualified ones. The temperature range is one issue out of dozens. This would hardly be the first time that the most desirable component was pure unobtanium. On Mon, Jul 22, 2024 at 3:35 PM Starr Moffatt via AMSAT-BB < amsat-bb(a)amsat.org> wrote: > Batteries are often the first major things to fail. > (AO7 failed then re-awoke when the battery open circuited). > > I would suggest instead of having a battery, use ultra capacitors to > help even out the power from the solar cells when in sunlight, and, have > no transponder operation when in eclipse. > > Additional advantages are: (1) ultra capacitors are lighter than a > battery, (2) the solar cells need only supply the transponder, whereas > there needs to be extra solar cells to also recharge the discharged > battery when the bird is in sunlight. > > The only disadvantage is the transponder is non operational during > eclipse periods, which, in reality, is no big issue. > > 73 Starr ZL3CU > > On 23/07/2024 5:15 am, JOHN GEIGER via AMSAT-BB wrote: > > Thanks for the information on all of those things. Hopefully someday we > > can see some more FM satellites with this sort of lifespan! > > > > 73 John AF5CC > > > > Sent using Zoho Mail <{0}> > > > > > > > > > > ---- On Mon, 22 Jul 2024 12:06:57 -0500 *Paul Stoetzer via AMSAT-BB > > <amsat-bb(a)amsat.org>* wrote --- > > > > 1. It's a microsat size satellite, so significantly larger than > > current cubesat form factors. > > 2. It's transmit power is just 250 mW and it transmits only while it > > receives a signal with a 67 Hz PL tone - there's no constant carrier > > or any telemetry transmissions. I'm not aware of any other payloads > > or signals coming from the satellite. Potentially there's not even > > any onboard computer drawing power. > > 3. Given its size, it has fairly large solar cells and likely has > > fairly large battery cells and given its transmit setup, the depth > > of discharge is likely quite low. NiCd batteries can last a real > > long time when the depth of discharge is kept quite low. > > > > 73, > > > > Paul, N8HM > > > > On Mon, Jul 22, 2024 at 12:05 PM JOHN GEIGER via AMSAT-BB > > <amsat-bb(a)amsat.org <mailto:amsat-bb@amsat.org>> wrote: > > > > __ > > > > SO-50 will be 22 years old in December and seems to be still be > > going strong, in sunlight and in eclipse. No other satellite > > launched since then has lived near that long. So what is SO-50s > > key to long life? Is it how the satellite was built? Something > > in its operation, like lower power on transmit? Its orbital > setup? > > > > Any ideas why it has lived so much longer than the recent crop > > of AMSATS? > > > > 73 John AF5CC > > > > Sent using Zoho Mail > > > > > > > > > > ----------------------------------------------------------- > > > > Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes > > this open forum available > > to all interested persons worldwide without requiring > > membership. Opinions expressed > > are solely those of the author, and do not reflect the official > > views of AMSAT-NA. > > Acceptable Use and Privacy Policies available at > > https://www.amsat.org/about-amsat/ > > <https://www.amsat.org/about-amsat/> > > > > View archives of this mailing list at > > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > > <https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org> > > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > > <http://amsat.org> > > Manage all of your AMSAT-NA mailing list preferences at > > https://mailman.amsat.org <https://mailman.amsat.org> > > > > > > ----------------------------------------------------------- > > > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum > available > > to all interested persons worldwide without requiring membership. > > Opinions expressed > > are solely those of the author, and do not reflect the official > > views of AMSAT-NA. > > Acceptable Use and Privacy Policies available at > > https://www.amsat.org/about-amsat/ < > https://www.amsat.org/about-amsat/> > > > > View archives of this mailing list at > > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > > <https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org> > > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > > Manage all of your AMSAT-NA mailing list preferences at > > https://mailman.amsat.org <https://mailman.amsat.org> > > > > > > > > > > ----------------------------------------------------------- > > > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > > to all interested persons worldwide without requiring membership. > Opinions expressed > > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > > > View archives of this mailing list at > > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org -- Bruce Perens K6BP

1 0

Re: SO-50 Key to Longivity?
by Jim White 22 Jul '24

22 Jul '24

Managing the battery discharge by adjusting current draws - by turning things on/off or changing the power level of the transmitter, has been done since the 1990 AMSAT Microsats (or the SSTL birds before them). At least we did that in one the ones I worked on. I think it's still true that the most common cause of satellite failure is batteries doing bad, and the one's I'm familiar with were because the batteries got pulled down to the resting voltage (about 1V/cell for NiCads). They will reverse polarity or short when you mistreat them. With chemistries like LiPoly, if you mistreat them they just die, or explode. You prevent that by making sure you never pull the voltage too low, and by not overcharging them. Another feature in the Microsats was to reduce battery charging when they got near "full" by moving the solar panel off the optimum point in the I/V curve. I have seen many examples of missions that sat on the shelf for months with the battery (whatever chemistry) discharging. Then at separation they turn on a bunch of stuff and, drew the batteries into the ditch, reset, and maybe came back on. And a few that did that over and over until operators managed to stop it by command. Or they died. In the Microsats, and others I worked on, we took a very conservative approach. At sep, turn on only what is absolutely needed, beacon at a slow rate and lower power, let the batteries charge up and let the operators decide when to turn on the ACS or other stuff - after being sure there was enough power available. So to the extent batteries are managed properly as in Falconsat 3 and SO50, yes, that definitely extends the life. Having said that if you design goal is a year of operation at higher TX power with a full ACS running, or gathering a lot of science data, you accept the satellite life will be shorter. It's all a trade-off. Actually, many trade-offs all tangled up with each other. Jim On 7/22/2024 4:17 PM, Brian Wilkins via AMSAT-BB wrote: > Jim > > Did the TX timer help to extend the life of the satellite? > > 73, ko4aqf(a)gmail.com > > > On Mon, Jul 22, 2024 at 1:17 PM Jim White via AMSAT-BB > <amsat-bb(a)amsat.org> wrote: > > I'll provide a bit of input here since I worked on SO50. Here are > some considerations. > > - The hardware was mostly built by SpaceQuest and used proven > designs that had been flown several times > > - The design goal was long life. The orbits would provide that, > unlike some current launches were the orbit will last a shorter > time. The idea was to provide a long life resource for all to use. > > - The software followed proven designs dating back to the 1990 > Microsats. All software except the boot loader (in rad protected > RAM) was uploadeable. The SCOS real-time operating system allowed > individual tasks to be killed and uploaded without disturbing > other tasks or the OS. SCOS was quite robust. > > - There were no I2C busses to latch up, and no flash cards (both > of which cause problems in current designs) > > - The program memory was rad hard, the OS 'washed' that memory > every 10 minutes to eliminate bit flips from passing through the > SAA. The data memory used Huffman software rad recovery. > > - Antennas we not deploy-able and were made of piano wire so were > quite robust. > > - The batteries were NiCAD so were robust and hard to hurt. They > work fine over a wide temperature range and don't need heaters. > Don't need to manage charging as carefully and don't need to be > concerned about not charging if outside a temp range. > > - The software automatically adjusted TX power output to prevent > pulling the battery V too low and causing a reset. There were > three steps of battery management, each turning off more stuff to > reduce load and attempt to prevent full discharge. > > - Batteries were very carefully matched using the process first > developed for the Microsats. > > - The power system included adjusting the solar panel input > impedance to constantly maximize power from the panels. And > another algorithm prevented overcharging. A manual process is used > to adjust those algorithms as the battery capacity drops with time > and the panels loose efficiency. > > - The software kept the dept of discharge of the batteries to no > more than about 20%, resulting in much longer battery life. > > Jim, WD0E > > > On 7/22/2024 10:46 AM, JOHN GEIGER via AMSAT-BB wrote: >> Unfortunately I don't know much about IO-117 so that is a >> question I can't answer. >> >> 73 John AF5CC >> >> Sent using Zoho Mail >> >> >> >> >> ---- On Mon, 22 Jul 2024 11:31:20 -0500 *<crohtun(a)aim.com> >> <mailto:crohtun@aim.com>* wrote --- >> >> And what have we learned from IO-117 about radiation >> resistance, etc? >> >> Ray Crafton KN2K >> >> >> Sent from the all new AOL app for iOS >> <https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661> >> >> On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB >> <amsat-bb(a)amsat.org> wrote: >> >> >> SO-50 will be 22 years old in December and seems to be >> still be going strong, in sunlight and in eclipse. No >> other satellite launched since then has lived near that >> long. So what is SO-50s key to long life? Is it how the >> satellite was built? Something in its operation, like >> lower power on transmit? Its orbital setup? >> >> Any ideas why it has lived so much longer than the recent >> crop of AMSATS? >> >> 73 John AF5CC >> >> Sent using Zoho Mail >> >> >> >> >> ----------------------------------------------------------- >> >> Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. >> AMSAT-NA makes this open forum available >> to all interested persons worldwide without requiring >> membership. Opinions expressed >> are solely those of the author, and do not reflect the >> official views of AMSAT-NA. >> Acceptable Use and Privacy Policies available at >> https://www.amsat.org/about-amsat/ >> >> View archives of this mailing list at >> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >> To unsubscribe send an email to >> amsat-bb-leave(a)amsat.org <http://amsat.org> >> Manage all of your AMSAT-NA mailing list preferences at >> https://mailman.amsat.org >> >> >> >> >> >> ----------------------------------------------------------- >> >> Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes this open forum available >> to all interested persons worldwide without requiring membership. Opinions expressed >> are solely those of the author, and do not reflect the official views of AMSAT-NA. >> Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ >> >> View archives of this mailing list at >> https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org >> To unsubscribe send an email to amsat-bb-leave(a)amsat.org <http://amsat.org> >> Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes > this open forum available > to all interested persons worldwide without requiring membership. > Opinions expressed > are solely those of the author, and do not reflect the official > views of AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > <http://amsat.org> > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org

1 0

Re: SO-50 Key to Longivity?
by Starr Moffatt 22 Jul '24

22 Jul '24

Batteries are often the first major things to fail. (AO7 failed then re-awoke when the battery open circuited). I would suggest instead of having a battery, use ultra capacitors to help even out the power from the solar cells when in sunlight, and, have no transponder operation when in eclipse. Additional advantages are: (1) ultra capacitors are lighter than a battery, (2) the solar cells need only supply the transponder, whereas there needs to be extra solar cells to also recharge the discharged battery when the bird is in sunlight. The only disadvantage is the transponder is non operational during eclipse periods, which, in reality, is no big issue. 73 Starr ZL3CU On 23/07/2024 5:15 am, JOHN GEIGER via AMSAT-BB wrote: > Thanks for the information on all of those things. Hopefully someday we > can see some more FM satellites with this sort of lifespan! > > 73 John AF5CC > > Sent using Zoho Mail <{0}> > > > > > ---- On Mon, 22 Jul 2024 12:06:57 -0500 *Paul Stoetzer via AMSAT-BB > <amsat-bb(a)amsat.org>* wrote --- > > 1. It's a microsat size satellite, so significantly larger than > current cubesat form factors. > 2. It's transmit power is just 250 mW and it transmits only while it > receives a signal with a 67 Hz PL tone - there's no constant carrier > or any telemetry transmissions. I'm not aware of any other payloads > or signals coming from the satellite. Potentially there's not even > any onboard computer drawing power. > 3. Given its size, it has fairly large solar cells and likely has > fairly large battery cells and given its transmit setup, the depth > of discharge is likely quite low. NiCd batteries can last a real > long time when the depth of discharge is kept quite low. > > 73, > > Paul, N8HM > > On Mon, Jul 22, 2024 at 12:05 PM JOHN GEIGER via AMSAT-BB > <amsat-bb(a)amsat.org <mailto:amsat-bb@amsat.org>> wrote: > > __ > > SO-50 will be 22 years old in December and seems to be still be > going strong, in sunlight and in eclipse. No other satellite > launched since then has lived near that long. So what is SO-50s > key to long life? Is it how the satellite was built? Something > in its operation, like lower power on transmit? Its orbital setup? > > Any ideas why it has lived so much longer than the recent crop > of AMSATS? > > 73 John AF5CC > > Sent using Zoho Mail > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org <http://amsat.org>. AMSAT-NA makes > this open forum available > to all interested persons worldwide without requiring > membership. Opinions expressed > are solely those of the author, and do not reflect the official > views of AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > <https://www.amsat.org/about-amsat/> > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > <https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org> > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > <http://amsat.org> > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org <https://mailman.amsat.org> > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. > Opinions expressed > are solely those of the author, and do not reflect the official > views of AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ <https://www.amsat.org/about-amsat/> > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > <https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org> > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org <https://mailman.amsat.org> > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Re: SO-50 Key to Longivity?
by Brian Wilkins 22 Jul '24

22 Jul '24

Jim Did the TX timer help to extend the life of the satellite? 73, ko4aqf(a)gmail.com On Mon, Jul 22, 2024 at 1:17 PM Jim White via AMSAT-BB <amsat-bb(a)amsat.org> wrote: > I'll provide a bit of input here since I worked on SO50. Here are some > considerations. > > - The hardware was mostly built by SpaceQuest and used proven designs that > had been flown several times > > - The design goal was long life. The orbits would provide that, unlike > some current launches were the orbit will last a shorter time. The idea > was to provide a long life resource for all to use. > > - The software followed proven designs dating back to the 1990 Microsats. > All software except the boot loader (in rad protected RAM) was > uploadeable. The SCOS real-time operating system allowed individual tasks > to be killed and uploaded without disturbing other tasks or the OS. SCOS > was quite robust. > > - There were no I2C busses to latch up, and no flash cards (both of which > cause problems in current designs) > > - The program memory was rad hard, the OS 'washed' that memory every 10 > minutes to eliminate bit flips from passing through the SAA. The data > memory used Huffman software rad recovery. > > - Antennas we not deploy-able and were made of piano wire so were quite > robust. > > - The batteries were NiCAD so were robust and hard to hurt. They work > fine over a wide temperature range and don't need heaters. Don't need to > manage charging as carefully and don't need to be concerned about not > charging if outside a temp range. > > - The software automatically adjusted TX power output to prevent pulling > the battery V too low and causing a reset. There were three steps of > battery management, each turning off more stuff to reduce load and attempt > to prevent full discharge. > > - Batteries were very carefully matched using the process first developed > for the Microsats. > > - The power system included adjusting the solar panel input impedance to > constantly maximize power from the panels. And another algorithm prevented > overcharging. A manual process is used to adjust those algorithms as the > battery capacity drops with time and the panels loose efficiency. > > - The software kept the dept of discharge of the batteries to no more than > about 20%, resulting in much longer battery life. > > Jim, WD0E > > > On 7/22/2024 10:46 AM, JOHN GEIGER via AMSAT-BB wrote: > > Unfortunately I don't know much about IO-117 so that is a question I can't > answer. > > 73 John AF5CC > > Sent using Zoho Mail > > > > ---- On Mon, 22 Jul 2024 11:31:20 -0500 * <crohtun(a)aim.com> > <crohtun(a)aim.com>* wrote --- > > And what have we learned from IO-117 about radiation resistance, etc? > > Ray Crafton KN2K > > > Sent from the all new AOL app for iOS > <https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661> > > On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB < > amsat-bb(a)amsat.org> wrote: > > > SO-50 will be 22 years old in December and seems to be still be going > strong, in sunlight and in eclipse. No other satellite launched since then > has lived near that long. So what is SO-50s key to long life? Is it how > the satellite was built? Something in its operation, like lower power on > transmit? Its orbital setup? > > Any ideas why it has lived so much longer than the recent crop of AMSATS? > > 73 John AF5CC > > Sent using Zoho Mail > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ > > View archives of this mailing list athttps://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org

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Re: SO-50 Key to Longivity?
by Ivan Molina 22 Jul '24

22 Jul '24

Thanks Jim for the valuable information. KN6EN Yahoo Mail: Search, Organize, Conquer On Mon, Jul 22, 2024 at 10:17 AM, Jim White via AMSAT-BB<amsat-bb(a)amsat.org> wrote: I'll provide a bit of input here since I worked on SO50. Here are some considerations. - The hardware was mostly built by SpaceQuest and used proven designs that had been flown several times - The design goal was long life. The orbits would provide that, unlike some current launches were the orbit will last a shorter time. The idea was to provide a long life resource for all to use. - The software followed proven designs dating back to the 1990 Microsats. All software except the boot loader (in rad protected RAM) was uploadeable. The SCOS real-time operating system allowed individual tasks to be killed and uploaded without disturbing other tasks or the OS. SCOS was quite robust. - There were no I2C busses to latch up, and no flash cards (both of which cause problems in current designs) - The program memory was rad hard, the OS 'washed' that memory every 10 minutes to eliminate bit flips from passing through the SAA. The data memory used Huffman software rad recovery. - Antennas we not deploy-able and were made of piano wire so were quite robust. - The batteries were NiCAD so were robust and hard to hurt. They work fine over a wide temperature range and don't need heaters. Don't need to manage charging as carefully and don't need to be concerned about not charging if outside a temp range. - The software automatically adjusted TX power output to prevent pulling the battery V too low and causing a reset. There were three steps of battery management, each turning off more stuff to reduce load and attempt to prevent full discharge. - Batteries were very carefully matched using the process first developed for the Microsats. - The power system included adjusting the solar panel input impedance to constantly maximize power from the panels. And another algorithm prevented overcharging. A manual process is used to adjust those algorithms as the battery capacity drops with time and the panels loose efficiency. - The software kept the dept of discharge of the batteries to no more than about 20%, resulting in much longer battery life. Jim, WD0E On 7/22/2024 10:46 AM, JOHN GEIGER via AMSAT-BB wrote: Unfortunately I don't know much about IO-117 so that is a question I can't answer. 73 John AF5CC Sent using Zoho Mail ---- On Mon, 22 Jul 2024 11:31:20 -0500 <crohtun(a)aim.com> wrote --- And what have we learned from IO-117 about radiation resistance, etc? Ray Crafton KN2K Sent from the all new AOL app for iOS On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB <amsat-bb(a)amsat.org> wrote: SO-50 will be 22 years old in December and seems to be still be going strong, in sunlight and in eclipse. No other satellite launched since then has lived near that long. So what is SO-50s key to long life? Is it how the satellite was built? Something in its operation, like lower power on transmit? Its orbital setup? Any ideas why it has lived so much longer than the recent crop of AMSATS? 73 John AF5CC Sent using Zoho Mail ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Upcoming ARISS Contact Schedule as of 2024-07-22 19:00 UTC
by aj9n＠aol.com 22 Jul '24

22 Jul '24

Upcoming ARISS Contact Schedule as of 2024-07-22 19:00 UTC Quick list of scheduled contacts and events: Aznakaevsky district schools of the Republic of Tatarstan, Tatarstan Russia, direct via TBD The ISS callsign is presently scheduled to be RSØISS The downlink frequency is presently scheduled to be 145.800 MHz The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The scheduled crewmember is Aleksandr Grebyonkin RZ3DSE The ARISS mentor is RV3DR Contact is go for Sat 2024-07-27 13:45 UTC Arizona Science Center, Phoenix, AZ, telebridge via AB1OC The ISS callsign is presently scheduled to be NA1SS The downlink frequency is presently scheduled to be 145.800 MHz The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The scheduled crewmember is Matthew Dominick KCØTOR The ARISS mentor is K4RGK Contact is go: Sat 2024-07-27 18:24:08 UTC 41 deg Narayama ARISS School Contact, Nara, Japan, direct via TBD The ISS callsign is presently scheduled to be OR4ISS (***) The downlink frequency is presently scheduled to be 145.800 MHz The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The scheduled crewmember is Mike Barratt KD5MIJ (***) The ARISS mentor is 7M3TJZ Contact is go for: Mon 2024-07-29 10:56:40 UTC 59 deg (***) SMPIT Nurul Ishlah, Banda Aceh, Indonesia, telebridge via VK4ISS (***) The ISS callsign is presently scheduled to be NA1SS (***) The downlink frequency is presently scheduled to be 145.800 MHz The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The scheduled crewmember is Sunita Williams KD5PLB (***) The ARISS mentor is VE3TBD Contact is go for: Fri 2024-08-02 12:45:31 UTC 25 deg (***) Kopernik Observatory, Vestal, NY, mentor direct via K2ZRO The ISS callsign is presently scheduled to be NA1SS The downlink frequency is presently scheduled to be 145.800 MHz The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The scheduled crewmember is Jeanette Epps KF5QNU (***) The ARISS mentor is AB1OC Contact is go for: Fri 2024-08-02 16:45:22 UTC 79 deg (***) Watch for Livestream at https://youtube.com/live/Tv3x3D0DTzU?feature=share The crossband repeater continues to be active. If any crewmember is so inclined, all they have to do is pick up the microphone, raise the volume up, and talk on the crossband repeater. So give a listen, you just never know. Note, all times are approximate. It is recommended that you do your own orbital prediction or start listening about 10 minutes before the listed time. All dates and times listed follow International Standard ISO 8601 date and time format YYYY-MM-DD HH:MM:SS The complete schedule page has been updated as of 2024-07-22 19:00 UTC. (***) Here you will find a listing of all scheduled school contacts, and questions, other ISS related websites, IRLP and Echolink websites, and instructions for any contact that may be streamed live. https://www.amsat.org/amsat/ariss/news/arissnews.rtf https://www.amsat.org/amsat/ariss/news/arissnews.txt The successful school list has been updated as of 2024-07-18 15:00 UTC. https://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf ####################################################################################################################################### Comments on making general contacts I have been seeing a lot of traffic on Facebook and I suspect on other social media sites with people asking why they are not hearing the crew make general contacts. First off the crew is very busy on the ISS and they simply may not have the time to just pick up the microphone and talk. Also, one needs to be aware of their normal daily schedule. I have listed below the constraints that we at ARISS have to follow in order to schedule the school contacts. Hopefully this will help you better schedule your opportunities. Typical daily schedule Wakeup to Workday start= 1.5 hours Workday start to Workday end=12 hours Workday end to Sleep= 2 hours Sleep to wakeup= 8.5 hours The crew's usual waking period is 07:30 – 19:30 UTC. The most common times to find a crew member making casual periods are about one hour after waking up and about an hour before sleeping, when they have personal time. They're usually free most of the weekend, as well. SSTV events are not that often. So please check out https://www.ariss.org/ for the latest information or watch for the ARISS announcements. And don’t forget that the packet system is sometimes active. Check the status at https://www.ariss.org/ or http://www.issfanclub.eu to see if the packet system is active or not. As always, if there is an EVA, a docking, or an undocking; the ARISS radios are turned off as part of the safety protocol. The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The latest list of frequencies in use can be found at https://www.ariss.org/contact-the-iss.html ######################################################################################################################################## A multi-point telebridge contact means that each student will be on the telebridge from their own home. **************************************************************************************************************************************** ARISS is very aware of the impact that COVID-19 is having on schools and the public in general. As such, we may have last minute cancellations or postponements of school contacts. As always, I will try to provide everyone with near-real-time updates. Watch for future COVID-19 related announcements at https://www.ariss.org/ The following schools have now been postponed or cancelled due to COVID-19: Postponed: No new schools Cancelled: No new schools **************************************************************************************************************************************** The ARISS webpage is at https://www.ariss.org/ Note that there are links to other ARISS websites from this site. The main page for Applying to Host a Scheduled Contact may be found at https://www.ariss.org/apply-to-host-an-ariss-contact.html +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS Contact Applications (United States) Call for Proposals The next proposal window for US schools and educational organizations to host an Amateur Radio contact with a crew member on board the ISS opens July 8, 2024 for contacts to be scheduled for January 1, 2025 – June 30, 2025. This proposal window is due to ARISS by September 6, 2024 at 11:59 PM Pacific Time (Sept. 7, 2024, 06:59 UTC). (***) Proposal information and more details such as expectations, proposal guidelines and the proposal form can be found at www.ariss.org. An ARISS Introductory Webinar session will be held on July 22, 2024, at 7 PM ET (23:00 UTC). The Zoom link to sign up is: https://us06web.zoom.us/meeting/register/tZErf-ihrDktG9OphYxAjfz7nbONV0YcwY… (***) Find more information and proposal instructions, visit the ARISS-USA website at: https://ariss-usa.org/hosting-an-ariss-contact-in-the-usa/ Please direct any questions to ariss.us.education(a)gmail.com. For future proposal information and more details such as expectations, proposal guidelines and proposal form, and dates and times of Information Webinars, go to www.ariss.org. About ARISS: Amateur Radio on the International Space Station (ARISS) is a cooperative venture of international amateur radio societies and the space agencies that support the International Space Station (ISS). In the United States, sponsors are the Radio Amateur Satellite Corporation (AMSAT), the American Radio Relay League (ARRL), the ISS National Lab and National Aeronautics and Space Administration (NASA). The primary goal of ARISS is to promote exploration of science, technology, engineering, and mathematics (STEAM) topics by organizing scheduled contacts via amateur radio between crew members aboard the ISS and students in classrooms or public forms. Before and during these radio contacts, students, educators, parents, and communities learn about space, space technologies, and amateur radio. For more information, see www.ariss.org. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS Contact Applications (Europe, Africa and the Middle East) Schools and Youth organizations in Europe, Africa and the Middle East interested in setting up an ARISS radio contact with an astronaut on board the International Space Station are invited to submit an application from September to October and from February to April. Please refer to details and the application form at www.ariss-eu.org/school-contacts. Applications should be addressed by email to: school.selection.manager(a)ariss-eu.org ARISS Contact Applications (Canada, Central and South America, Asia and Australia and Russia) +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Organizations outside the United States can apply for an ARISS contact by filling out an application. Please direct questions to the appropriate regional representative listed below. If your country is not specifically listed, send your questions to the nearest ARISS Region listed. If you are unsure which address to use, please send your question to the ARISS-Canada representative; they will forward your question to the appropriate coordinator. For the application, go to: https://www.ariss.org/ariss-application.html. ARISS-Canada and the Americas, except USA: Steve McFarlane, VE3TBD email to: ve3tbd(a)gmail.com ARISS-Japan, Asia, Pacific and Australia: Satoshi Yasuda, 7M3TJZ email to: ariss(a)iaru-r3.org, Japan Amateur Radio League (JARL) https://www.jarl.org/ ARISS-Russia: Soyuz Radioljubitelei Rossii (SRR) https://srr.ru/ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS is always glad to receive listener reports for the above contacts. ARISS thanks everyone in advance for their assistance. Feel free to send your reports to aj9n(a)amsat.org or aj9n(a)aol.com. Listen for the ISS on the downlink of 145.8Ø MHz unless otherwise noted. ******************************************************************************* All ARISS contacts are made via the Kenwood radio unless otherwise noted. ******************************************************************************* Several of you have sent me emails asking about the RAC ARISS website and not being able to get in. That has now been changed to https://www.ariss.org/ Note that there are links to other ARISS websites from this site. **************************************************************************** Looking for something new to do? How about receiving DATV from the ISS? Please note that the HamTV system is back on board but awaiting re-installation. Please monitor ARISS-EU or ARISS-ON for the very latest news on the troubleshooting efforts. If interested, then please go to the ARISS-EU website for complete details. Look for the buttons indicating Ham Video. http://www.ariss-eu.org/ If you need some assistance, ARISS mentor Kerry N6IZW, might be able to provide some insight. Contact Kerry at kbanke(a)sbcglobal.net The HamTV webpage: https://www.amsat-on.be/hamtv-summary/ **************************************************************************** ARISS congratulates the following mentors who have now mentored over 100 schools: Sergey RV3DR with 239 Francesco IKØWGF with 154 Satoshi 7M3TJZ with 152 Gaston ON4WF with 124 Peter IN3GHZ with 119 Steve VE3TBD with 106 **************************************************************************** The webpages listed below were all reviewed for accuracy. Out of date webpages were removed, and new ones have been added. If there are additional ARISS websites I need to know about, please let me know. Total number of ARISS ISS to earth school events is 1736. Each school counts as 1 event. Total number of ARISS ISS to earth school contacts is 1641. Each contact may have multiple schools sharing the same time slot. Total number of ARISS supported terrestrial contacts is 48. Please feel free to contact me if more detailed statistics are needed. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The following US states and entities have never had an ARISS contact: South Dakota, American Samoa, Guam, Northern Marianas Islands, and the Virgin Islands. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ QSL information may be found at: https://www.ariss.org/qsl-cards.html ISS callsigns: DPØISS, FXØISS, GB1SS, IRØISS, NA1SS, OR4ISS, RSØISS **************************************************************************** Frequency chart for packet, voice, and crossband repeater modes showing Doppler correction as of 2005-07-29 04:00 UTC https://www.amsat.org/amsat/ariss/news/ISS_frequencies_and_Doppler_correcti… Check out the Zoho reports of the ARISS contacts https://reports.zoho.com/ZDBDataSheetView.cc?DBID=412218000000020415 **************************************************************************** Exp. 70 on orbit Oleg Kononenko Nikolay Chub Exp. 71 on orbit Tracy E. Caldwell Dyson SpaceX Crew-8 on orbit Matthew Dominick KCØTOR Mike Barratt KD5MIJ Jeanette Epps KF5QNU Aleksandr Grebyonkin RZ3DSE **************************************************************************** 73, Charlie Sufana AJ9N One of the ARISS operation team mentors

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Re: SO-50 Key to Longivity?
by Jim White 22 Jul '24

22 Jul '24

I'll provide a bit of input here since I worked on SO50. Here are some considerations. - The hardware was mostly built by SpaceQuest and used proven designs that had been flown several times - The design goal was long life. The orbits would provide that, unlike some current launches were the orbit will last a shorter time. The idea was to provide a long life resource for all to use. - The software followed proven designs dating back to the 1990 Microsats. All software except the boot loader (in rad protected RAM) was uploadeable. The SCOS real-time operating system allowed individual tasks to be killed and uploaded without disturbing other tasks or the OS. SCOS was quite robust. - There were no I2C busses to latch up, and no flash cards (both of which cause problems in current designs) - The program memory was rad hard, the OS 'washed' that memory every 10 minutes to eliminate bit flips from passing through the SAA. The data memory used Huffman software rad recovery. - Antennas we not deploy-able and were made of piano wire so were quite robust. - The batteries were NiCAD so were robust and hard to hurt. They work fine over a wide temperature range and don't need heaters. Don't need to manage charging as carefully and don't need to be concerned about not charging if outside a temp range. - The software automatically adjusted TX power output to prevent pulling the battery V too low and causing a reset. There were three steps of battery management, each turning off more stuff to reduce load and attempt to prevent full discharge. - Batteries were very carefully matched using the process first developed for the Microsats. - The power system included adjusting the solar panel input impedance to constantly maximize power from the panels. And another algorithm prevented overcharging. A manual process is used to adjust those algorithms as the battery capacity drops with time and the panels loose efficiency. - The software kept the dept of discharge of the batteries to no more than about 20%, resulting in much longer battery life. Jim, WD0E On 7/22/2024 10:46 AM, JOHN GEIGER via AMSAT-BB wrote: > Unfortunately I don't know much about IO-117 so that is a question I > can't answer. > > 73 John AF5CC > > Sent using Zoho Mail <{0}> > > > > > ---- On Mon, 22 Jul 2024 11:31:20 -0500 *<crohtun(a)aim.com>* wrote --- > > And what have we learned from IO-117 about radiation resistance, etc? > > Ray Crafton KN2K > > > Sent from the all new AOL app for iOS > <https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661> > > On Monday, July 22, 2024, 12:02 PM, JOHN GEIGER via AMSAT-BB > <amsat-bb(a)amsat.org> wrote: > > > SO-50 will be 22 years old in December and seems to be still > be going strong, in sunlight and in eclipse. No other > satellite launched since then has lived near that long. So > what is SO-50s key to long life? Is it how the satellite was > built? Something in its operation, like lower power on > transmit? Its orbital setup? > > Any ideas why it has lived so much longer than the recent crop > of AMSATS? > > 73 John AF5CC > > Sent using Zoho Mail > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum > available > to all interested persons worldwide without requiring > membership. Opinions expressed > are solely those of the author, and do not reflect the > official views of AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > > > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Acceptable Use and Privacy Policies available athttps://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences athttps://mailman.amsat.org

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Re: SO-50 Key to Longivity?
by JOHN GEIGER 22 Jul '24

22 Jul '24

Thanks for the information on all of those things. Hopefully someday we can see some more FM satellites with this sort of lifespan! 73 John AF5CC Sent using {0} ---- On Mon, 22 Jul 2024 12:06:57 -0500 Paul Stoetzer via AMSAT-BB <amsat-bb(a)amsat.org> wrote --- 1. It's a microsat size satellite, so significantly larger than current cubesat form factors.2. It's transmit power is just 250 mW and it transmits only while it receives a signal with a 67 Hz PL tone - there's no constant carrier or any telemetry transmissions. I'm not aware of any other payloads or signals coming from the satellite. Potentially there's not even any onboard computer drawing power. 3. Given its size, it has fairly large solar cells and likely has fairly large battery cells and given its transmit setup, the depth of discharge is likely quite low. NiCd batteries can last a real long time when the depth of discharge is kept quite low. 73, Paul, N8HM On Mon, Jul 22, 2024 at 12:05 PM JOHN GEIGER via AMSAT-BB <mailto:amsat-bb@amsat.org> wrote: SO-50 will be 22 years old in December and seems to be still be going strong, in sunlight and in eclipse. No other satellite launched since then has lived near that long. So what is SO-50s key to long life? Is it how the satellite was built? Something in its operation, like lower power on transmit? Its orbital setup? Any ideas why it has lived so much longer than the recent crop of AMSATS? 73 John AF5CC Sent using ----------------------------------------------------------- Sent via AMSAT-BB(a)http://amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)http://amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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