NOSS 3-4: progress toward required altitude

From: Ted Molczan (ssl2molcz@rogers.com)
Date: Mon Oct 08 2007 - 09:16:48 EDT

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    The following graphic shows the progress of NOSS 3-4 (07027A / 31701 and 07027C
    / 31708) toward their required orbital altitude, in terms of the percentage of
    the shortfall in altitude that has been corrected. As of October 5, about 58
    percent of the shortfall had been made up.
    
    http://satobs.org/seesat_ref/NOSS_3-4/NOSS_3-4_altitude_progress.pdf
    
    The plot is of 07027A, but that of 07027C would be virtually identical, since
    their manoeuvres have almost always been nearly identical in timing and
    magnitude.
    
    Had the trend of Jul 17 - Aug 11 been sustained, then they would have reached
    the nominal insertion mean altitude (about 1106 km) by about Oct 10. They would
    still have had to correct the inclination, and presumably the 30 deg too-low
    argument of perigee.
    
    After a two week hiatus, manoeuvres resumed on Aug 25, and have set a pace trend
    indicates that they will reach the required altitude about Dec 03. I have yet to
    analyze the slower rate of climb since Aug 25. It could be that the manoeuvre
    have been smaller and/or less frequent; and/or perhaps some of the delta-V has
    been put toward shifting the argument of perigee, which was 30 deg too low. I
    notice in recent elements, that the argument of perigee has increased several
    degrees.
    
    Once the nominal insertion orbit has been achieved, we can expect several more
    manoeuvres, to establish the required along-track and planar spacing between the
    spacecraft. The previous three NOSS 3 missions took about 4 weeks to complete
    those manoeuvres.
    
    Ted Molczan
    
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