Re: Can we get them to fix AO-40 first then?
In a message dated 14/10/2009 23:17:11 GMT Standard Time, n1miw@cox.net writes:
My final thought on this is - if you can't get the receiver to decode commands, it's a loss, end of story. If it will receive, make it open the panels to get more power to the bird. Once the satellite is fully illuminated by the sun during its rotation, then try to work on stabilizing the satellite. Until that is tried, I personally feel that not every last attempt at reviving AO-40 has been attempted,
Hi.
The first time I read the post, I thought simply, no power = no receiver so no command to the satellite.
But then, I thought of something else.
When AO-40 was built, it would be launched with all systems off. When released into space some hardware would have switched on the receivers and a transmitter for telemetry.
Now, it's sitting there with a shorted battery.....or is it?
If the battery were to open circuit, then the satellite may think it's being switched on for the first time. But with AO-40 I seem to remember that telemetry was on 2m.
The significance of your idea and my memory....is that the 2m transmitter does not work. So we would need to send a command to turn the S band transmitter on.
It is virtually impossible for S band to just appear, like AO-7 did if it is not the default mode at switch on. But it completely justifies your idea of sending a command at it every now and again.
Thanks for the thought
Regards
David
Yes, that is an interesting point. What happens if it does come on, but cannot transmit? When power is restored, what will the satellite do, if anything? I guess only the command stations would have a chance to get it to send telemetry on 2.4GHz. I don't remember what happened to the 2M downlink, but time to check the archives. -----Original Message----- From: G0MRF@aol.com [mailto:G0MRF@aol.com] Sent: Wednesday, October 14, 2009 7:44 PM To: n1miw@cox.net Cc: amsat-bb@AMSAT.Org Subject: Re: [amsat-bb] Re: Can we get them to fix AO-40 first then?
In a message dated 14/10/2009 23:17:11 GMT Standard Time, n1miw@cox.net writes: My final thought on this is - if you can't get the receiver to decode commands, it's a loss, end of story. If it will receive, make it open the panels to get more power to the bird. Once the satellite is fully illuminated by the sun during its rotation, then try to work on stabilizing the satellite. Until that is tried, I personally feel that not every last attempt at reviving AO-40 has been attempted, Hi.
The first time I read the post, I thought simply, no power = no receiver so no command to the satellite.
But then, I thought of something else.
When AO-40 was built, it would be launched with all systems off. When released into space some hardware would have switched on the receivers and a transmitter for telemetry.
Now, it's sitting there with a shorted battery.....or is it?
If the battery were to open circuit, then the satellite may think it's being switched on for the first time. But with AO-40 I seem to remember that telemetry was on 2m.
The significance of your idea and my memory....is that the 2m transmitter does not work. So we would need to send a command to turn the S band transmitter on.
It is virtually impossible for S band to just appear, like AO-7 did if it is not the default mode at switch on. But it completely justifies your idea of sending a command at it every now and again.
Thanks for the thought
Regards
David
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ
I think both those things are accurate.
Robert WB5MZO
Date: Wed, 14 Oct 2009 21:31:30 -0400 From: mat_62@netcommander.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@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
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Has there been any serious attempt to take a photograph of the damaged bird using ground based optical telescopes while it is in sunlight ? With modern telescopes such as http://www.refractortelescopes.co.uk/reviews/orion/orion-shorttube-80-a-refr... or similiar and a modern digital camera and a known RA/DEC co-ordinate of the satellite at any point in its orbit, it should be possible get a fairly decent picture of what is still up there...
Note RA / DEC are astronomy co-ordinates which should be able to be calculated from AZ/EL or TLE, but I may not be able to do it myself.
We don't need to track it, but just to image it in several consecutive frames. From: http://www.emergentspace.com/pubs/AIAA_GNC_2002_AMSAT_A040.pdf
Table 1. Nominal Orbit Parameters for AO-40 Orbit Parameter Value Semimajor Axis (km) 36,245 Perigee Height (km) 1,042 Apogee Height (km) 58,691 Eccentricity 0.797 Inclination (deg) 6.04 Period (hours) 19.1
On Wed, Oct 14, 2009 at 9:49 PM, Rocky Jones orbitjet@hotmail.com wrote:
I think both those things are accurate.
Robert WB5MZO
Date: Wed, 14 Oct 2009 21:31:30 -0400 From: mat_62@netcommander.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@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
Hotmail: Powerful Free email with security by Microsoft. http://clk.atdmt.com/GBL/go/171222986/direct/01/ _______________________________________________ Sent via AMSAT-BB@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
The "national intellegence assets" which would be needed to get an image of AO-40 that "showed things" are probably there...but if you see the pictures they have to kill you (grin).
I know amateurs who have imaged -40 and done so enough to measure the light curve from it.
Robert WB5MZO _________________________________________________________________ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/171222985/direct/01/
There is no need for any specialised photo intelligence assets, simple telescopes with enough F/D and gain will do, there are many amateur astronomers who have imaged craters on the moon (e.g.., google astrophotography) also see http://www.footootjes.nl/Astrophotography_Lunar/Astrophotography_Lunar.html
Question is do we have any amateur astronomer who is also amsat enthusiast ?
On Wed, Oct 14, 2009 at 10:29 PM, Rocky Jones orbitjet@hotmail.com wrote:
The "national intellegence assets" which would be needed to get an image of AO-40 that "showed things" are probably there...but if you see the pictures they have to kill you (grin).
I know amateurs who have imaged -40 and done so enough to measure the light curve from it.
Hope to hear from them if they are on the list..
I bet that is not enough resolution
Robert WB5MZO
From: samudra.haque@gmail.com Date: Wed, 14 Oct 2009 22:39:42 -0400 Subject: Re: [amsat-bb] Re: Can we get them to fix AO-40 first then? To: orbitjet@hotmail.com CC: mat_62@netcommander.com; amsat-bb@amsat.org
There is no need for any specialised photo intelligence assets, simple telescopes with enough F/D and gain will do, there are many amateur astronomers who have imaged craters on the moon (e.g.., google astrophotography) also see http://www.footootjes.nl/Astrophotography_Lunar/Astrophotography_Lunar.html
Question is do we have any amateur astronomer who is also amsat enthusiast ?
On Wed, Oct 14, 2009 at 10:29 PM, Rocky Jones orbitjet@hotmail.com wrote:
The "national intellegence assets" which would be needed to get an image of AO-40 that "showed things" are probably there...but if you see the pictures they have to kill you (grin).
I know amateurs who have imaged -40 and done so enough to measure the light curve from it.
Hope to hear from them if they are on the list..
_________________________________________________________________ Hotmail: Free, trusted and rich email service. http://clk.atdmt.com/GBL/go/171222984/direct/01/
Hi Samudra et all,
very interesting article and links you've sent out. So far, I did not heard about attempts to take photographs, at least not in the public. However, there is no reason to believe that the satellite disintegrated, since there are now other objects tracked around it.
The command stations regularly sent commands to AO-40 in the last years, but I guess with larger time between those attempts now. AO-40 was launched with the IHU "hot", that means: After separation and release of the safety/separation switch, the 24V power for the transmitter was switched ON and after some waiting time, the Beacon was commanded ON by the IHU (integrated housekeeping unit). The electronics were designed that way, if for example the IHU crashes, the I/O ports will remain in their last state and the transmitter would be kept on. However if there is a complete power loss (as we expect with the battery shortened), all Output ports will indeed reset to their default state, which is "all off"... (The BCR's default values normaly should still produce enough power) For this reason, the command stations prepared a small boot-block for the IHU to configure the BCR (battery charge regulator) and the Trasmitter status, for example S-band Beacon On. If this would be successful, command stations could start to reload the IHU, etc.. We also still plan to use our 20m dish in Bochum to uplink commands with high power or listen for some week signals.
73s Peter DB2OS
Samudra Haque wrote:
Has there been any serious attempt to take a photograph of the damaged bird using ground based optical telescopes while it is in sunlight ? With modern telescopes such as http://www.refractortelescopes.co.uk/reviews/orion/orion-shorttube-80-a-refr... or similiar and a modern digital camera and a known RA/DEC co-ordinate of the satellite at any point in its orbit, it should be possible get a fairly decent picture of what is still up there...
Note RA / DEC are astronomy co-ordinates which should be able to be calculated from AZ/EL or TLE, but I may not be able to do it myself.
We don't need to track it, but just to image it in several consecutive frames. From: http://www.emergentspace.com/pubs/AIAA_GNC_2002_AMSAT_A040.pdf
Table 1. Nominal Orbit Parameters for AO-40 Orbit Parameter Value Semimajor Axis (km) 36,245 Perigee Height (km) 1,042 Apogee Height (km) 58,691 Eccentricity 0.797 Inclination (deg) 6.04 Period (hours) 19.1
On Wed, Oct 14, 2009 at 9:49 PM, Rocky Jones orbitjet@hotmail.com wrote:
I think both those things are accurate.
Robert WB5MZO
Date: Wed, 14 Oct 2009 21:31:30 -0400 From: mat_62@netcommander.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@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
Hotmail: Powerful Free email with security by Microsoft. http://clk.atdmt.com/GBL/go/171222986/direct/01/ _______________________________________________ Sent via AMSAT-BB@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@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
Uuuupsss...
Just a short remark - "However, there is no reason to believe that the satellite disintegrated, since there are *now* other objects tracked around it."
Indeed I meant there are *no* other objects around AO-40 ;-)
Thanks to Graham for pointing this out...
73s Peter DB2OS
Peter Guelzow wrote:
Hi Samudra et all,
very interesting article and links you've sent out. So far, I did not heard about attempts to take photographs, at least not in the public. However, there is no reason to believe that the satellite disintegrated, since there are now other objects tracked around it.
The command stations regularly sent commands to AO-40 in the last years, but I guess with larger time between those attempts now. AO-40 was launched with the IHU "hot", that means: After separation and release of the safety/separation switch, the 24V power for the transmitter was switched ON and after some waiting time, the Beacon was commanded ON by the IHU (integrated housekeeping unit). The electronics were designed that way, if for example the IHU crashes, the I/O ports will remain in their last state and the transmitter would be kept on. However if there is a complete power loss (as we expect with the battery shortened), all Output ports will indeed reset to their default state, which is "all off"... (The BCR's default values normaly should still produce enough power) For this reason, the command stations prepared a small boot-block for the IHU to configure the BCR (battery charge regulator) and the Trasmitter status, for example S-band Beacon On. If this would be successful, command stations could start to reload the IHU, etc.. We also still plan to use our 20m dish in Bochum to uplink commands with high power or listen for some week signals.
73s Peter DB2OS
Samudra Haque wrote:
Has there been any serious attempt to take a photograph of the damaged bird using ground based optical telescopes while it is in sunlight ? With modern telescopes such as http://www.refractortelescopes.co.uk/reviews/orion/orion-shorttube-80-a-refr... or similiar and a modern digital camera and a known RA/DEC co-ordinate of the satellite at any point in its orbit, it should be possible get a fairly decent picture of what is still up there...
Note RA / DEC are astronomy co-ordinates which should be able to be calculated from AZ/EL or TLE, but I may not be able to do it myself.
We don't need to track it, but just to image it in several consecutive frames. From: http://www.emergentspace.com/pubs/AIAA_GNC_2002_AMSAT_A040.pdf
Table 1. Nominal Orbit Parameters for AO-40 Orbit Parameter Value Semimajor Axis (km) 36,245 Perigee Height (km) 1,042 Apogee Height (km) 58,691 Eccentricity 0.797 Inclination (deg) 6.04 Period (hours) 19.1
On Wed, Oct 14, 2009 at 9:49 PM, Rocky Jones orbitjet@hotmail.com wrote:
I think both those things are accurate.
Robert WB5MZO
Date: Wed, 14 Oct 2009 21:31:30 -0400 From: mat_62@netcommander.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@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
Hotmail: Powerful Free email with security by Microsoft. http://clk.atdmt.com/GBL/go/171222986/direct/01/ _______________________________________________ Sent via AMSAT-BB@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@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@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
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO _________________________________________________________________ Hotmail: Powerful Free email with security by Microsoft. http://clk.atdmt.com/GBL/go/171222986/direct/01/
If the power budget were not positive as of the last known configuration, i.e. solar panels produced enough power to run the spacecraft AND charge the batteries, we would have been dead long before the event (whatever it was) because the batteries need to be charged enough to run us through eclipses. So if the panels were illuminated there would be sufficient power to run the bus. However, the IHU software load would be minimal and we would have more than enough power. However, if the batteries shorted the bus, and drew it down, then probably nothing would run and we are in the "pray for AO-7" mode with MUCH better batteries than we had in AO-7, making a repeat less likely. With AO-10, we got lucky. The thing would just come up default in a mode that we could use until it finally gave up the ghost.
Bob
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO _________________________________________________________________
Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/
I am pleasantly amused by the interest in all probability of a dead bird. Can you imagine the explosion in interest and excitement on this bb if it ever came back. It would be nice but we can only play with L/S modes on the occasional AO-51.
73 Bob W7LRD
----- Original Message ----- From: "Peter Guelzow" peter.guelzow@kourou.de To: "Rocky Jones" orbitjet@hotmail.com Cc: "Amsat BB" amsat-bb@amsat.org, "samudra haque" samudra.haque@gmail.com Sent: Thursday, October 15, 2009 2:30:03 PM GMT -08:00 US/Canada Pacific Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/
_______________________________________________ Sent via AMSAT-BB@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
I reached out today and talked to a professional astronomer, and here is the response. Before we start a project to actually take a detailed photo of the AO-40 in Space, could someone work with me directly to determine the coordinates that we could provide as requested:
Hi Samudra,
We would have to know the exact coordinates ahead of time, point the telescope there, then start imaging as it flies through the field of view.
Since we've never done it, I don't know how doable it actually is. I'm pretty certain we don't have the cameras...
It's possible, but we would need more info and possible differetn equipment.
The group I approached is a reputable one associated with their own observatory, locally to the Washington DC area. If anyone is interested to help out with the mathematics required, please contact me directly at n3rdx@amsat.org. I know of two other groups who can be approached locally, but we must given them all the details of size/configuration etc. Could be an interesting intellectual challenge while people are waiting for new sats to be designed.
-samudra
On Thu, Oct 15, 2009 at 5:30 PM, Peter Guelzow peter.guelzow@kourou.de wrote:
Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/
if a 'special' camera is required, often, cameras (even really good ones, or special purpose ) can be rented for a short time for a very very reasonable rate
On Oct 15, 2009, at 6:53 PM, Samudra Haque wrote:
I reached out today and talked to a professional astronomer, and here is the response. Before we start a project to actually take a detailed photo of the AO-40 in Space, could someone work with me directly to determine the coordinates that we could provide as requested:
Hi Samudra,
We would have to know the exact coordinates ahead of time, point the telescope there, then start imaging as it flies through the field of view.
Since we've never done it, I don't know how doable it actually is. I'm pretty certain we don't have the cameras...
It's possible, but we would need more info and possible differetn equipment.
The group I approached is a reputable one associated with their own observatory, locally to the Washington DC area. If anyone is interested to help out with the mathematics required, please contact me directly at n3rdx@amsat.org. I know of two other groups who can be approached locally, but we must given them all the details of size/configuration etc. Could be an interesting intellectual challenge while people are waiting for new sats to be designed.
-samudra
On Thu, Oct 15, 2009 at 5:30 PM, Peter Guelzow <peter.guelzow@kourou.de
wrote: Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/
Sent via AMSAT-BB@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
Myles Landstein myles.landstein@gmail.com please note my new email address dti will soon be eliminated , gmail is my new home update your dir
Hello Peter and thanks for the reply...sorry mine was so late, busy afternoon.
you answered my question. I had "heard" that with the arrays folded or based on some failures...that AO-40 did not have 360 degree coverage in solar cells around its spin access.
If that was the case then the battery was going to be essential for any type of recovery...but since it is not accurate then I agree if the battery will open (do a "seven") then the only question would be the Solar angle.
Thank you for a very good and straight forward answer 73
Robert WB5MZO
Date: Thu, 15 Oct 2009 23:30:03 +0200 From: peter.guelzow@kourou.de To: orbitjet@hotmail.com CC: samudra.haque@gmail.com; amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: Can we get them to fix AO-40 first then?
Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/
_________________________________________________________________ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/171222985/direct/01/
So, IF the battery un-shorts, IF the IHU boots and resets the beacon (S-band, I assume). Therefore, for the rest of us, occasional monitoring the beacon frequency would be good (using the current keps to estimate Doppler offset). IF detected, then commands could be attempted. Sounds like a lot of IF's. Is this a good reason to keep your S-band downlink equipment working? Think about it.
Integrity of S/C is unknown, so its all a big guessing game.
I remain available (when QRV on L-band with 865 kW EIRP) for command attempts (lat=60.675N, Lon=151.316W).
73, Ed - KL7UW
At 07:20 PM 10/15/2009, Rocky Jones wrote:
Hello Peter and thanks for the reply...sorry mine was so late, busy afternoon.
you answered my question. I had "heard" that with the arrays folded or based on some failures...that AO-40 did not have 360 degree coverage in solar cells around its spin access.
If that was the case then the battery was going to be essential for any type of recovery...but since it is not accurate then I agree if the battery will open (do a "seven") then the only question would be the Solar angle.
Thank you for a very good and straight forward answer 73
Robert WB5MZO
Date: Thu, 15 Oct 2009 23:30:03 +0200 From: peter.guelzow@kourou.de To: orbitjet@hotmail.com CC: samudra.haque@gmail.com; amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: Can we get them to fix AO-40 first then?
Hi Robert,
that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems...
73s Peter
Rocky Jones wrote:
Peter.
In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to "spin" and maintain the DC busses without a battery?
Robert WB5MZO
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73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
On Oct 15 2009, Edward Cole wrote:
So, IF the battery un-shorts, IF the IHU boots and resets the beacon (S-band, I assume). Therefore, for the rest of us, occasional monitoring the beacon frequency would be good (using the current keps to estimate Doppler offset). IF detected, then commands could be attempted. Sounds like a lot of IF's. Is this a good reason to keep your S-band downlink equipment working? Think about it.
Integrity of S/C is unknown, so its all a big guessing game.
I remain available (when QRV on L-band with 865 kW EIRP) for command attempts (lat=60.675N, Lon=151.316W).
73, Ed - KL7UW
Perhaps my analogy to a comatose patient was a little bit off the mark, in that I was trying to say that just having a command station turn on their equipment, point their antennas, and give the command to release the solar panels did not have a high probability of success.
What I neglected to say, since I had incorrectly assumed that everyone on the list already knew it, was that ever since AO-40 went silent for the last time, at least one command station has regularly been sending commands to the old gal, not with the intent of releasing the solar panels, but with the intent of at least getting her interacting with the command station and doing things like turning on the S-band transmitter to get some telemetry, etc.
Peter also mentioned in one of his recent posts that command station(s) still do this on a regular, although perhaps less frequent, basis.
As has now been described, if the batteries STOPPED presenting a dead short to the power bus, unlike AO-7 which simply came alive, AO-40 would probably NOT automatically announce its re-birth, because the default beacon (2 meters) is not functional. It would take a command from a command station to turn on the S-band transmitter for anyone (like a command station operator) to know that she was capable of listening any more. So, even though it is a low probability scenario, it is still worth sending the appropriate commands to AO-40 on a regular basis just on the off chance that she had emerged partly from her coma.
It's pretty inexpensive to simply send some RF with appropriate commands her way, so there is very little downside to trying. I know that AMSAT doesn't give out command information freely, for obvious reasons, but there were several control stations active when she was alive, and adding one or more staffed by reliable folks who can be trusted with the information should be possible. . .
Do I hear someone volunteering? :)
73 de W0JT
Ed. yeap a lot of ifs. The good news is that Peter confirms that there (was anyway) power from solar cells all around the spin axis...hence it is possible in theory that if the short clears then things could wake up (solar angles etc).
Stranger things have happened. Many years ago we found an airplane that had sat in a hanger for almost 20 years in "semi storage". took some modest precautions "turning it on", got a ferry permit and the engine took us home to Norfolk (that was home then)...
I bet if you went to the Moon and put fresh batteries in the lunar rovers...they would turn on! (well 50 percent chance anyway)...
There is a better chance in my view that Oscar III will all of a sudden start up...
73 Robert WB5MZO
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Michael,
The Politically Correct term is "Propulsion Incident." More seriously, there were almost certainly cables and wires with damaged insulation which nevertheless worked fine where they were. Now imagine them flexing or being disturbed, as would be the case if they attempted to deploy the solar arrays. For that matter, suppose only one array deployed. That would have prevented the spin stabilization which was being used. There were a lot of hard choices made, but they were done with considerable thought and with the benefit of much experience and consultation.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Michael Tondee Sent: 14 October, 2009 20:32 To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Can we get them to fix AO-40 first then?
I guess I need to go back and read the archives because what I remember reading didn't give me any hope AO-40 would ever be back. Wasn't there something about that they believed the spacecraft was leaking corrosive fuel? Doesn't sound to conducive to any type of recovery of anything where electronics are involved.. I also thought there was talk of a "catastrophic explosion". Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@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
participants (12)
-
Alan P. Biddle -
Bob McGwier -
Bob- W7LRD -
Edward Cole -
G0MRF＠aol.com -
Larry -
Michael Tondee -
myles landstein -
Peter Guelzow -
Rocky Jones -
Samudra Haque -
tosca005＠umn.edu