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[aprssig] PCSAT status report.

Robert Bruninga bruninga at usna.edu
Sun Dec 14 13:41:33 UTC 2008


PCSAT status:

For the first time in 7 years, we were not able to fully recover
PCSAT during this full sun period despite the efforts of a
number of dedicated volunteers around the world.  Full sun
periods occur when passes are at sunrise and sunset to earth
observers.  PCSAT gets sun 24 hours a day then, but only on the
side panels.  It is an interesting conundrum that when PCSAT is
in full sun its average power is worst because the sun only hits
the side panels, but if we can recover it once, then we can
lower the average power and keep it alive. (we have been
unsuccessful this time).

On the other hand, a month later, the peak power available (on
the best -Z panel) occurs during the worst case eclipses,
(midday passes in the Northern hemisphere) so then there are
strong packets for 20 minutes or so, Recovery is very reliable,
but useless since then 15 minutes later she goes into 35 minute
darkness and she dies.  But she is useable during the middle of
those sunny side passes which will be approaching in mid
January.  Anyway, this is not the last you will hear of PCSAT,
but there will probably not be any more several week full sun,
full recovery periods as there have been in the past.

Remember that PCSAT has its best panel pointing along the
magnetic field lines of the Earth towards the South Magnetic
pole of the Earth, and so if you are good at 3D visualization,
it is easy to see what is happening.  There is a plot on the
PCSAT web page, and when I get back to it, I will make another
plot showing what it looks like during the peak period above.

See www.aprs.org/pcsat.html

Sun angle is worsening for my location, and this being nearest
the winter solstace, the sun won't get any better.   Full sun
period in Feb will not be as good as this one was.  The good
news is that I
think a colleage of mine will develop a better magnetic attitude
model so we can know better exactly when is the max power on the
spacecraft.  It should be entirely predictible, so that we do
not waste any time on poor angles.

I really appreciate all the efforts of so many operators.

This is my last day for this season due to some long expected
family news last night I will be on travel to Alabama  for the
next weeks and doubt I will get much email access.

So play packet on the ISS and thanks again for all your
efforts!

Bob, WB4APR






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