[amsat-bb] What happened on ISS on Jan 10?

[Udo Schneider <uschndr@xxxxxxxxxxxxxxxxxx>]

Hello,

just for fun I played a bit with the RAAN values of ISS:

I made a linear fitting for this year from

    RAAN = f(epo) or

meanRAAN = A + B*epo

and calculated the difference between meanRAAN
and RAAN given by the 2liners:

deltaRAAN = RAAN - meanRAAN

The result is shown in
http://userpage.fu-berlin.de/~uschndr/archive/RAAN2.GIF

I think the quasi sinewave form is made by the precession
of the orbital axis of ISS.

BUT: There is a remarkable change after the undocking
of the shuttles STS-109 and STS-110 (why?) and the
same effect on Jan 10 - there was no shuttle, no
russian spacecraft...

Any explanations by the experts?

73, Udo, DL7OL

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