If the ARISSat-1 satellite goes into eclipse, and the battery has failed, the software doesn't get to decide when to shut down. The lights are out with no power.
On Aug 27, 2011, at 3:00 PM, [email protected] wrote:
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Today's Topics:
- CM86/CM96 rare grid activation this Saturday August 27. (John Papay)
- ARISSat-1 (Carl Rimmer)
- Re: ARISSAT-1 (Clint Bradford)
- Re: some exceedingly clever technology (i8cvs)
- Re: ARISSat-1 (Pete MI0VAX)
- Southwest Texas Grids - August 22/23 SUCCESS! (Clayton Coleman W5PFG)
- Arissat-1 transponder LAST NIGHT OVER UK (paul robinson)
- Re: ARISSat-1 (Ransom, Kenneth G. (JSC-OC)[BARRIOS TECHNOLOGY])
- Re: ARISSat-1 (James McBride)
- Re: ARISSat-1 (Douglas Quagliana)
- SO67 - HO68 Status (Ted)
Message: 1 Date: Fri, 26 Aug 2011 15:45:22 -0400 From: John Papay [email protected] To: [email protected] Subject: [amsat-bb] CM86/CM96 rare grid activation this Saturday August 27. Message-ID: [email protected] Content-Type: text/plain; charset="us-ascii"; format=flowed
Hello. K G 6 N U B/p received a positive response from his CM86 / CM96 grid activations last week from Santa Cruz California. To fill unmet demands for these grids, especially CM86, he will be traveling to the CM86/CM96 grid boundary this Saturday August 27th. For those needing cards, a SASE sent the FCC ULS listed address is appreciated, but not required. Expect a 3-12 month turnaround. He always operates with 5W or less into a hand held yagi connected to a full duplex radio. The operation plan is as follows:
QTH: -122.0/37.0
Object AOS (utc) LOS grid(s)
SO-50 19:47 19:59 CM86/CM96 AO-27 20:04 20:15 CM86/CM96 AO-27 21:41 21:56 CM86 AO-51 22:10 22:22 CM86/CM96 AO-27 23:26 23:33 CM86 AO-51 23:47 00:02 CM86 AO-51 01:30 01:39 CM86(maybe)
73, John K8YSE
Message: 2 Date: Fri, 26 Aug 2011 22:59:54 -0400 From: Carl Rimmer [email protected] To: [email protected] Subject: [amsat-bb] ARISSat-1 Message-ID: [email protected] Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames where forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF
Message: 3 Date: Fri, 26 Aug 2011 20:38:56 -0700 From: Clint Bradford [email protected] To: AMSAT BB [email protected] Subject: [amsat-bb] Re: ARISSAT-1 Message-ID: [email protected] Content-Type: text/plain; CHARSET=US-ASCII
... I was having a really good pass ... went silent ... 08-27-2011 0241 UTC pass over Lake Erie ...
All the more reason for EVERYONE to report their work on the OSCAR Status site at ...
Our reports help not only "meager" fellow hams, but also the control operators of the various satellites up there!
Clint, K6LCS http://tinyurl.com/ARISSAT1-STATUS
Message: 4 Date: Sat, 27 Aug 2011 09:13:29 +0200 From: "i8cvs" [email protected] To: [email protected], "R Oler" [email protected] Cc: Amsat BB [email protected] Subject: [amsat-bb] Re: some exceedingly clever technology Message-ID: 000001cc6489$5f28ac60$0401a8c0@b3o7f1 Content-Type: text/plain; charset="iso-8859-1"
Hi Phil, KA9Q
What you describes using both magnetorquers ,momentum wheels and CCD video cameras for the attitude control system is what was made on AO40 but it was a big satellite and not a microsatellite.
73" de
i8CVS Domenico
----- Original Message ----- From: "Phil Karn" [email protected] To: "R Oler" [email protected] Cc: "Amsat BB" [email protected] Sent: Friday, August 26, 2011 6:54 PM Subject: [amsat-bb] Re: some exceedingly clever technology
On 8/24/11 8:11 PM, R Oler wrote:
Thrusters are necessary for orbit control, but for attitude control (which I think we really need) you'd *really* prefer something that doesn't consume a fuel.
These attitude control systems come in basically two types: magnetorquers and reaction wheels. Magnetorquers exchange angular momentum with the earth by acting on its magnetic field, but they tend to be slow, imprecise and require complex control and sensing systems including a magnetometer far enough from the spacecraft to get away from its own magnetic fields.
Reaction wheels come in two kinds: momentum wheels and control moment gyros. Momentum wheels change speed while control moment gyros don't. The latter seem much more common in spacecraft but I'd investigate both. They're good for quick, accurate pointing like you'd need to keep an antenna pointed down or a solar panel pointed at the sun.
Having both a magnetorquer and a set of wheels can be advantageous as the magnetorquer can be used occasionally to dump accumulated angular momentum from the wheels should it build up from small external torques.
Controlling attitude also means measuring it, and for this I keep thinking about small, cheap CCD video cameras. If we could build good enough sunshades we could snap pictures of star fields and look them up in a database. If you can match multiple stars in an image, then a single image could fix the attitude of the spacecraft. But I'd want to put a camera on each surface if possible. They could also sense the sun and the earth, though that's not as simple as it might seem. The sun usually overloads a CCD and produces streaks while the earth is very large in LEO. It might be possible to recognize the limb of the earth and get better precision that way. A lot would depend on the software processing these images, and it would be a challenge to write.
-Phil, KA9Q
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Message: 5 Date: Sat, 27 Aug 2011 12:33:34 +0100 From: Pete MI0VAX [email protected] To: [email protected] Cc: cfri[email protected] Subject: [amsat-bb] Re: ARISSat-1 Message-ID: CA[email protected] Content-Type: text/plain; charset=ISO-8859-1
Hi Carl,
I've seen this recently myself too.. On the occasions when it happened here over the UK, the bird "should" have been in high power mode, but after looking at telemetry it appears that it had switched into low power mode much earlier that than usual, from memory the footprint was only half in eclipse. Also noticed that before it cuts off that there is usually 10-15 or so seconds of a silent carrier. On another occasion it cut out halfway through a SSTV transmission - this I'm almost certain shouldn't have happened due to the way the firmware was written.
Perhaps a bad solar panel contributing to low voltage when approaching eclipse? I had noticed one of the panel temps was over 75c on several passes.
It certainly looks like there is some intermittent problems beginning to raise their head, lets hope it's not a steady decline in the bird's performance as gathering the SSTV pics, telemetry etc has been a very enjoyable change to the usual FM/SSB activity.
73 de Pete
Mi0VAX
On Sat, Aug 27, 2011 at 3:59 AM, Carl Rimmer [email protected] wrote:
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames
where
forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Message: 6 Date: Sat, 27 Aug 2011 07:50:09 -0500 From: Clayton Coleman W5PFG [email protected] To: AMSAT [email protected] Subject: [amsat-bb] Southwest Texas Grids - August 22/23 SUCCESS! Message-ID: CA[email protected] Content-Type: text/plain; charset=ISO-8859-1
I want to thank all who supported my efforts to activate DL98/DL99 on the Texas/Mexico border. I also made quite a few contacts from EL07 in Laredo, Texas. Despite two border patrol inspection stations and three border patrol "drive-by's" while I was operating, the boundary operation went smoothly. APRS coverage was fairly poor for most of the trip unless I was in between major metropolitan areas in the Interstate 35 corridor.
My SO-50 operations weren't as smooth as on AO-27 and AO-51 because they were unplanned and I was working them from whatever place I was on the road at AOS. Sometimes it was *not* a great location.
Overall I ended up making 102 contacts from grids EM00, EM01, EM02, EL07, EL08, EL09, DL98, and DL99. I've already uploaded these contacts to Logbook of the World. If you would like a paper card, please email me the QSO details or go the usual direct/SASE route.
73, Clayton W5PFG EM21
Message: 7 Date: Sat, 27 Aug 2011 15:26:30 +0100 (BST) From: paul robinson [email protected] To: [email protected] Subject: [amsat-bb] Arissat-1 transponder LAST NIGHT OVER UK Message-ID: [email protected] Content-Type: text/plain; charset=iso-8859-1
rpt 5/7 sig last night via the transponder called cq a few times heard a EA station that was weak but didnt manage to work him.Its not easy to work but possable. 2E1EUB ?
Message: 8 Date: Sat, 27 Aug 2011 09:31:39 -0500 From: "Ransom, Kenneth G. (JSC-OC)[BARRIOS TECHNOLOGY]" [email protected] To: Carl Rimmer [email protected], "[email protected]" [email protected] Subject: [amsat-bb] Re: ARISSat-1 Message-ID: C[email protected] Content-Type: text/plain; charset="us-ascii"
Looks like the satellite entered eclipse about that time. The solar panels are all that is powering the satellite now.
Kenneth - N5VHO
From: [email protected] [[email protected]] On Behalf Of Carl Rimmer [[email protected]] Sent: Friday, August 26, 2011 9:59 PM To: [email protected] Subject: [amsat-bb] ARISSat-1
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames where forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Message: 9 Date: Sat, 27 Aug 2011 22:07:31 +0800 From: James McBride [email protected] To: a[email protected] Subject: [amsat-bb] Re: ARISSat-1 Message-ID: [email protected] Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi all, I found this morning in VK6 (approx. 03:45 UTC) the MET counter said 21min 45 sec, which is approx. the time ARISSat-1 would have come back into Sunlight. Strange thing is it was on High Power - got plenty of telemetry frames but was discharging at a great rate of knots.. Looking at the data it would seem there was more discharging than charging going on over it's first 21 minutes. 1 panel said 45v, the others were around 15v so the part that was facing direct sunlight was good. I will get another chance perhaps in a few hours to see if it's still alive when not in sunlight and will try to grab some more telemetry.
I have a jpg screenshot of telemetry with the position info from earlier if anyone would like it.
73 James VK6FJA
On 27/08/2011 7:33 PM, Pete MI0VAX wrote:
Hi Carl,
I've seen this recently myself too.. On the occasions when it happened here over the UK, the bird "should" have been in high power mode, but after looking at telemetry it appears that it had switched into low power mode much earlier that than usual, from memory the footprint was only half in eclipse. Also noticed that before it cuts off that there is usually 10-15 or so seconds of a silent carrier. On another occasion it cut out halfway through a SSTV transmission - this I'm almost certain shouldn't have happened due to the way the firmware was written.
Perhaps a bad solar panel contributing to low voltage when approaching eclipse? I had noticed one of the panel temps was over 75c on several passes.
It certainly looks like there is some intermittent problems beginning to raise their head, lets hope it's not a steady decline in the bird's performance as gathering the SSTV pics, telemetry etc has been a very enjoyable change to the usual FM/SSB activity.
73 de Pete
Mi0VAX
On Sat, Aug 27, 2011 at 3:59 AM, Carl Rimmer[email protected] wrote:
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames
where
forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF _______________________________________________ Sent via [email protected]. 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 [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Message: 10 Date: Sat, 27 Aug 2011 13:22:58 -0400 (EDT) From: Douglas Quagliana [email protected] To: [email protected], a[email protected] Subject: [amsat-bb] Re: ARISSat-1 Message-ID: [email protected] Content-Type: text/plain; charset="us-ascii"
Telemetry came into the Internet telemetry server up until 02:43:37 UTC Aug 27. Then there's no further telemetry until 3:35:46 UTC.
If you are receiving telemetry, please turn on the forwarding to the Internet telemetry server, and also please email in your .CSV files to telemetry at arissattlm dot org.
Douglas KA2UPW/5
-----Original Message----- From: Carl Rimmer [email protected] To: amsat-bb [email protected] Sent: Fri, Aug 26, 2011 10:09 pm Subject: [amsat-bb] ARISSat-1
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames where forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF
Message: 11 Date: Sat, 27 Aug 2011 11:54:42 -0700 From: "Ted" [email protected] To: [email protected] Subject: [amsat-bb] SO67 - HO68 Status Message-ID: F78C6EA03BAC437DB19630942D74BBF5@HamComputer Content-Type: text/plain; charset="us-ascii"
The SA AMSAT site states: "SO67 suffered another anomaly which means that all amateur activity has been suspended." I think the translation is RIP SO67 As for HO68, the CAMSAT web page is no longer there I take that as RIP HO68
TK K7TRK
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End of AMSAT-BB Digest, Vol 6, Issue 492
Lou McFadin W5DID ARISS US Hardware manager
Hi Lou,
When you're going into eclipse without a battery, what difference would it make if you could? :-)
But, this post is about a different question... As the spacecraft tumbles in direct sunlight, I understand that there are some orientations it might tumble through that result in not quite enough power to run everything. First, is that correct? And, if so, what choices can the IHU make in terms of lightening the load on the solar panels? I presume the tumble would be slow enough that you could see the power dip coming... Can the various downlink components, the university experiment, etc. be independently shut down?
Greg KO6TH
From: [email protected] Date: Sat, 27 Aug 2011 17:14:37 -0400 To: [email protected] Subject: [amsat-bb] Re: AMSAT-BB Digest, Vol 6, Issue 492
If the ARISSat-1 satellite goes into eclipse, and the battery has failed, the software doesn't get to decide when to shut down. The lights are out with no power.
I detected no noticible tumble recently. Is this the consensus, or is it so slow as to be un noticible?
If there is any spin at all, then it will be about the Z axis and thus the pointing of the Z axis will not change much.
And if it does not change much, and is pointing near the sun, then we woiuld have little power. If itis poiting closer to 90 degrees off the sun, then we would have good power.
As the spacecraft tumbles in direct sunlight, ...th ere are some orientations ...that result in not quite enough power to run everything.
So has anyone done a spin determination?
I guess this email is pretty useless. I began it thinking (wrongly) that a Z spin would change its orientation to the sun during each orbit and so we could determin from the power nulls where it was pointing. But once I got into the email, I realized that it's spin would be in inertial space and so its axis to the sun would be relatively fixed (except for any wobble). So in that case, any change (other than eclipses) in relative sun angle on the Z axis is going to be very slow changing.. (if I got this right... or not).
thanks Bob, WB4APR
-
Bob Bruninga -
Greg D. -
Louis McFadin