[amsat-bb] Re: geo stationary bird

[G0MRF@aol.com]

In a message dated 04/11/2007 15:41:26 GMT Standard Time,  
richard at g3rwl.demon.co.uk writes:

Does  anyone know if retired birds are switched ON or OFF once they get 
boosted into  a retirement orbit ?  Could still be useful to us even from  there.

73
Richard Limebear G3RWL



Hi Richard.
 
After the 15 year (ish) period, the satellite is normally switched off  as it 
can no longer point its high gain antennas at the correct point  on the earth 
after the station keeping fuel has run out.
 
For us it just means we need switchable antennas that can be  swapped 15 
years after launch.
 
In every day use I suspect there could well  be some loss of  service during 
eclipse. On GEO sats the DC power required to run the  transponders normally 
is a little less than the power from the solar  array.
 
However, when the satellite enters eclipse, the TV etc transponders  are run 
from the batteries. I suspect that at this point, AMSAT would be  switched off 
or into some low power mode until the eclipse has passed.  The  extra battery 
power needed for operation of AMSAT  and  the commercial transponder   during 
eclipse would require a significant mass increase of the  on-board batteries.
 
73
 
David