On the 2242UTC pass of AO-51 tonight, we will try for the first time to reverse the magnet and "flip" the orientation of the satellite. While we do this, the 435.300 transmitter will be shut off for about 10 minutes. If the reversal is successful, we should see some changes in signal levels and patterns. This particular maneuver has not attempted since launch.
I'd appreciate any signal reports or observations from this evening and the next few days be emailed to ao51-modes@amsat.org or ko4ma@amsat.org.
In related news, as the spacecraft spin inexplicably continues to slow, we are seeing increasingly larger dips in the spacecraft voltage when the panels are poorly aligned to the sun. The immediate result of this is that we have had to decrease the power on both transmitters to prevent discharging the batteries too deeply. We'll be working on mitigating strategies this coming month. This may include using existing software routines to automatically lower the downlink power during these dips in power production, or resolving to run one transmitter at a time instead of simultaneous digital and repeater downlinks.
73, Drew KO4MA AMSAT-NA VP Operations
Drew,
When you say "flip the orientation of the satellite", do you mean a physical change of the orientation or are you referring to some other orientation that is not necessarily a physical change (maybe a change in the RF polarization or something like that).
Is this being done in an attempt to mitigate the impact of the decreasing rate of spin?
73 David K6CDW
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Andrew Glasbrenner Sent: Wednesday, December 02, 2009 8:36 AM To: Amsat-BB Subject: [amsat-bb] AO-51 magnet reversal tonight
On the 2242UTC pass of AO-51 tonight, we will try for the first time to reverse the magnet and "flip" the orientation of the satellite. While we do this, the 435.300 transmitter will be shut off for about 10 minutes. If the reversal is successful, we should see some changes in signal levels and patterns. This particular maneuver has not attempted since launch.
I'd appreciate any signal reports or observations from this evening and the next few days be emailed to ao51-modes@amsat.org or ko4ma@amsat.org.
In related news, as the spacecraft spin inexplicably continues to slow, we are seeing increasingly larger dips in the spacecraft voltage when the panels are poorly aligned to the sun. The immediate result of this is that we have had to decrease the power on both transmitters to prevent discharging the batteries too deeply. We'll be working on mitigating strategies this coming month. This may include using existing software routines to automatically lower the downlink power during these dips in power production, or resolving to run one transmitter at a time instead of simultaneous digital and repeater downlinks.
73, Drew KO4MA AMSAT-NA VP Operations _______________________________________________ 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
David Wing wrote:
Drew,
When you say "flip the orientation of the satellite", do you mean a physical change of the orientation or are you referring to some other orientation that is not necessarily a physical change (maybe a change in the RF polarization or something like that).
It will be a physical reorientation of the spacecraft. There is a large reversible bar magnet that causes the spacecraft to align it's self to the the magnetic field of the planet, and we are going to remagnetize it in the opposite sense. Take a look at http://www.coloradosatellite.com/Papers/Motion.html, especially Figure 2, for a far better explanation than I can give.
Is this being done in an attempt to mitigate the impact of the decreasing rate of spin?
No, it's more finally testing the hardware experiment that was included over five years ago on AO-51. It may or may not have some effect on the spin. It'll be interesting to see!
73, Drew KO4MA
The commands were executed to reverse the magnet, and there did seem to be a change in signal strength by the end of the pass. I'm particularly interested in any signal reports from the Southern Hemisphere. Does AO-51 sound stronger than normal?
73, Drew KO4MA AMSAT-NA VP Operations
At 10:03 AM 12/3/2009, Andrew Glasbrenner wrote:
The commands were executed to reverse the magnet, and there did seem to be a change in signal strength by the end of the pass. I'm particularly interested in any signal reports from the Southern Hemisphere. Does AO-51 sound stronger than normal?
I've passed this onto AMSAT-VK for feedback from the AO-51 regulars. My sat station is still off the air, so I can't offer any assistance. :(
73 de VK3JED / VK3IRL http://vkradio.com
Hi,
You can get XW-1 Telemetry Format at http://www.amsat.org/amsat-new/satellites/documents/XW-1_Telemetry_Format.pd....
73 Alan, BA1DU www.camsat.cn
participants (4)
-
Alan Kung -
Andrew Glasbrenner -
David Wing -
Tony Langdon