L4 Oscillations

 

Update 2009. Lacrosse 5 can do the same thing. The period of the oscillations for L5 and L4 is 7 seconds. The peak magnitude here is around zero and again the angle qx was close to zero throughout the oscillation period. The required flare angle when the satellite brightened initially was 22 degrees and had reached 42 degrees at the end when the satellite entered eclipse. In this case the Sun seemed to be in the orbital plane and it flew almost directly overhead so no y-rotation was required. 

 

 

During the passes of Lacrosse 4 on 23/04/2006 and 25/06/2008 the brightness plots show interesting oscillations.

The data below is plotted with a time axis for 25/06/08. Each 2006 data point represents the same range as the equivalent 2008 point. The starting times are 20:57:41 in 2006 and 21:50:00 for 2008. Starting at these times the satellite range evolved in an almost identical way on each occasion. The key to the oscillations is the angle qx. During many passes this may dip close to zero which indicates the possibility of a flare but on these occasions it stays near zero all the time so there almost always a chance. 

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The satellite ranges plotted for every second subsequent to the start times stated.
 

 

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