[amsat-bb] PCSAT Spin rate still 0.6 RPM

Robert Bruninga bruninga at usna.edu
Thu Apr 3 13:09:01 PDT 2014

For what it's worth:  PCSAT is still maintaining a 0.6 RPM spin about the Z

Today for fun, we commanded PCSAT  and got 4 minutes of 10 second data.
During 100 seconds it completed 1 revolution which equates to 0.6 RPM, the
same rate as 13 years ago.

>From that we conclude that our (black/white) solar radiation differential
pressure spin system is still working fine.  AND that the white paint has
not changed in 13 years in space (it was very expensive unobtainium
two-part white space paint begged from a government launch agency).

Only the equatorial antennas are painted black and white on the front and
back to give us the Z spin.  The others were "Stanley yellow".

See the original photo on http://aprs.org/pcsat.html

As a refresher, in addition to this 0.6 RPM around the Z axis, there is
also the 0.02 RPM tumble about the Z axis since Z has a bar magnet to
follow the Earth's magnetic field which then tumbles once over each pole.

Users:  Routine Digipeating via PCSAT is not encouraged, since every now
and then (very rare) we do take a stab at commanding it, and invariably,
just when we are getting lucky, someone hits it with a packet for
digipeating and robs us of the ONE-PACKET chance we have of getting in.
But then we so rarely command it, that it does not make sense to insist
that no one use it either.

Just glad it is still working (sort of)...


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