Re: Fwd: Future radical satellite designs
Hello maggie- I hate it when people snip or take things out of context. Go back to the original entire email to absorb the reason. thanks, patrick
------- Original Message -------
From : Margaret Leber[mailto:maggie@voicenet.com]
Sent : 7/8/2007 8:27:59 AM To : amsat-bb@amsat.org Cc : Subject : RE: [amsat-bb] Fwd: Future radical satellite designs
On 7/8/07, Patrick McGrane N2OEQ@aceweb.com wrote:
Some will argue that they want continuous duty whenever the satellite is in
range, day or night.
I would like to see a longer lived satellite capable of full power half the
time that could
potentially last several decades in orbit.
That's really insightful. So many of the birds end up operating in that mode *anyway*; what could be accomplished if we designed them that way on purpose?
-- 73 de Maggie K3XS Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280
By the way, inbound email is broken on the address you're using: "SMTP Error (state 13): 550 5.1.1 Patrick.McGrane@aceweb.com is not a valid mailbox" _______________________________________________ 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
On 7/8/07, Patrick McGrane N2OEQ@aceweb.com wrote:
Hello maggie- I hate it when people snip or take things out of context. Go back to the original entire email to absorb the reason. thanks, patrick
I did read the whole thing.
The challenges to amateur secondary payloads on commercial or military spacecraft have been discussed here at length in the past. *My* comment was that a standalone bird *designed* without battery-powered transmitters might be an interesting approach.
As it stands now we have several birds on-orbit designed with larger battery systems (that have subsequently failed) that come up in various random control system states when they come out of eclipse. These birds only transmit when in sunlight anyway; what if we designed one that way on purpose? Now *that's* a "radical satellite design".
The payload weight that would have gone to bigger batteries to power transmitters during eclipse could be used for other equipment. A smaller (more reliable? certainly simpler and cheaper) auxiliary battery system could keep the control systems alive during eclipse. A lot of work is being done with ultra-low-power processor chips for mobile applications these days.
Imagine if AO-40 had used this approach (admittedly not at all in-line with the elaborate something-for-everyone AO-40 design philosophy); it might still be usable. As it is, when the complex power system failed, we lost the whole bird. And the only hope of recovering it is the outside chance that it might fail *again*.
-- 73 de Maggie K3XS Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280
Interesting discussion. For my $.02:
1. Consider a sun synchronous orbit to go along with the solar-only approach. No eclipse to worry about, though I'm not sure how many years such an orbit could be maintained before it slides one way or the other, e.g. what happened to AO-27 in reverse. So, you would still need to design for eclipse, just not operate there.
2. You don't get max power out of the cells all the time - it depends on sun angle. And solar cells degrade over time, and they fail too. Having a battery in the loop can be a very good thing, e.g. what happened to PCSAT. Perhaps a compromise, use some of those new mega capacitors? I understand that they are not space-rated yet, but perhaps "we" could help in that regard...
3. Not to burst your bubble, but I believe one of the cubesats recently launched uses a no-battery design.
4. We know AO-40's power system has failed, or at least is not capable of powering the bird. I haven't heard that we know cause vs effect; another "urp" of from the rocket system, or leaking nasty stuff all over the wires could be the cause. The battery itself could be just fine. But, I agree that there's a lot of mass and volume that could be used for other things on a small bird.
Greg KO6TH
----Original Message Follows---- From: "Margaret Leber" maggie@voicenet.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Future radical satellite designs Date: Sun, 8 Jul 2007 10:05:41 -0400
On 7/8/07, Patrick McGrane N2OEQ@aceweb.com wrote:
Hello maggie- I hate it when people snip or take things out of context. Go back to the original entire email to absorb the reason. thanks,
patrick
I did read the whole thing.
The challenges to amateur secondary payloads on commercial or military spacecraft have been discussed here at length in the past. *My* comment was that a standalone bird *designed* without battery-powered transmitters might be an interesting approach.
As it stands now we have several birds on-orbit designed with larger battery systems (that have subsequently failed) that come up in various random control system states when they come out of eclipse. These birds only transmit when in sunlight anyway; what if we designed one that way on purpose? Now *that's* a "radical satellite design".
The payload weight that would have gone to bigger batteries to power transmitters during eclipse could be used for other equipment. A smaller (more reliable? certainly simpler and cheaper) auxiliary battery system could keep the control systems alive during eclipse. A lot of work is being done with ultra-low-power processor chips for mobile applications these days.
Imagine if AO-40 had used this approach (admittedly not at all in-line with the elaborate something-for-everyone AO-40 design philosophy); it might still be usable. As it is, when the complex power system failed, we lost the whole bird. And the only hope of recovering it is the outside chance that it might fail *again*.
-- 73 de Maggie K3XS Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280 _______________________________________________ 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
_________________________________________________________________ Need a brain boost? Recharge with a stimulating game. Play now! http://club.live.com/home.aspx?icid=club_hotmailtextlink1
How about a 50 KW ERP EME station for power? All you need is some power rectifiers that work @ 2M and a long boom yagi on the satellite side and we have many EME stations in the US! First atempts of this I belive occured at Field Day, but the receiver front end protection diodes had too high an internal resistance prevnting full charging of the batteries on AO-51! My .02 Battery technoloigy is changing, and mutiple batteries with full management to drop unmatched cells an still have output should offer the best solution. AO-40 demise was related more to hangar age than anything else. Systems degrade with time, and we did not have a firm launch date when construction was started. In the future we need to make the batteries the last part to be purchased only after a launch commitment has been made. Several other lessons were learned from AO-40 and they too were related to the long time between the construction and launch of AO-40
Art, KC6UQH ----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: maggie@voicenet.com; amsat-bb@amsat.org Sent: Sunday, July 08, 2007 11:46 AM Subject: [amsat-bb] Re: Future radical satellite designs
Interesting discussion. For my $.02:
1. Consider a sun synchronous orbit to go along with the solar-only approach. No eclipse to worry about, though I'm not sure how many years such an orbit could be maintained before it slides one way or the other, e.g. what happened to AO-27 in reverse. So, you would still need to design for eclipse, just not operate there.
2. You don't get max power out of the cells all the time - it depends on sun angle. And solar cells degrade over time, and they fail too. Having a battery in the loop can be a very good thing, e.g. what happened to PCSAT. Perhaps a compromise, use some of those new mega capacitors? I understand that they are not space-rated yet, but perhaps "we" could help in that regard...
3. Not to burst your bubble, but I believe one of the cubesats recently launched uses a no-battery design.
4. We know AO-40's power system has failed, or at least is not capable of powering the bird. I haven't heard that we know cause vs effect; another "urp" of from the rocket system, or leaking nasty stuff all over the wires could be the cause. The battery itself could be just fine. But, I agree that there's a lot of mass and volume that could be used for other things on a small bird.
Greg KO6TH
----Original Message Follows---- From: "Margaret Leber" maggie@voicenet.com To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Future radical satellite designs Date: Sun, 8 Jul 2007 10:05:41 -0400
On 7/8/07, Patrick McGrane N2OEQ@aceweb.com wrote:
Hello maggie- I hate it when people snip or take things out of context. Go back to the original entire email to absorb the reason. thanks,
patrick
I did read the whole thing.
The challenges to amateur secondary payloads on commercial or military spacecraft have been discussed here at length in the past. *My* comment was that a standalone bird *designed* without battery-powered transmitters might be an interesting approach.
As it stands now we have several birds on-orbit designed with larger battery systems (that have subsequently failed) that come up in various random control system states when they come out of eclipse. These birds only transmit when in sunlight anyway; what if we designed one that way on purpose? Now *that's* a "radical satellite design".
The payload weight that would have gone to bigger batteries to power transmitters during eclipse could be used for other equipment. A smaller (more reliable? certainly simpler and cheaper) auxiliary battery system could keep the control systems alive during eclipse. A lot of work is being done with ultra-low-power processor chips for mobile applications these days.
Imagine if AO-40 had used this approach (admittedly not at all in-line with the elaborate something-for-everyone AO-40 design philosophy); it might still be usable. As it is, when the complex power system failed, we lost the whole bird. And the only hope of recovering it is the outside chance that it might fail *again*.
-- 73 de Maggie K3XS Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280 _______________________________________________ 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
_________________________________________________________________ Need a brain boost? Recharge with a stimulating game. Play now! http://club.live.com/home.aspx?icid=club_hotmailtextlink1
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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 (4)
-
Greg D. -
kc6uqh -
Margaret Leber -
Patrick McGrane