[amsat-bb] Re: geo stationary bird
G0MRF at aol.com
Sun Nov 4 12:48:15 PST 2007
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.
Richard Limebear G3RWL
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.
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