[amsat-bb] Re: AO-51 magnet reversal tonight

David Wing david at cdwing.com
Wed Dec 2 08:53:46 PST 2009


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?


-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at 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 

I'd appreciate any signal reports or observations from this evening and 
the next few days be emailed to ao51-modes at amsat.org or ko4ma at 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
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