[amsat-bb] can RF change the orientation of a satellite?

Auke de Jong, VE6PWN sparkycivic at shaw.ca
Sat Oct 23 18:44:26 PDT 2010

I couldn't help but notice that on this website 
http://www.intelsat.com/resources/galaxy-15/faqs.asp about "zombiesat" 
Galaxy 15, Intelsat figures that the lack of RF on thr transponder package 
since their loss of control earlier this year, will actually make it take 
longer to saturate it's momentum-wheel orientation stablizer system.  This, 
compared to the manufacturer's original estimate of achieving the saturation 
condition beuing several months sooner having assumed normal full-load of RF 
on the transponders.

My question is: How is this possible?  Does the RF put acceleration-forces 
on the transmitting antenna of the satellite similar to ion propulsion, or 
does the uplink RF push on the receiving antenna?  Is there some other 
mechanism that can electronically alter the forces acting on the body of the 
satellite based on the amount of RF power?


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