Re: BSTAR value

From: Mgr. CSc. Antonn Vtek (AVitek@seznam.cz)
Date: Tue Apr 20 2004 - 03:18:55 EDT

  • Next message: Thomas Fly: "Re: BSTAR value"

    ================= Původní zpráva =================
    Od (From): "Ed Cannon" <ecannon@mail.utexas.edu>
    Komu (To): seesat-l@satobs.org
    Kopie (Cc): 
    Předmět (Subject): Re: BSTAR value
    Datum (Date): 20. 4. 2004 7:23
    ==================================================
    
    > >Looking closer on the BSTAR drag value of the ISS over time, 
    > >I noticed that it is varying by around 10% with a period of 
    > >about 20 days.
    > 
    > What about where its perigee is -- at the equator versus 
    > elsewhere, and is the perigee occurring in darkness or 
    > daylight?  This yields four conditions:
    > 
    > near equator in daylight (most drag)
    > near equator in darkness
    > away from equator in daylight
    > away from equator in darkness (least drag)
    > 
    
    But IMHO the most pronounced effect on BSTAR change is with the switch between XPOP and LVLH orientation of ISS!? Try to correlate the BSTAR changes with those orientation changes. For timetable of changes see eg. NASA ISS On-Orbit Status archive at my site:
    
    http://www.lib.cas.cz/www/space.40/MRPO/INDEX.HTM
    
    
    
    
    Mgr. Antonin Vitek, CSc.
    
    Office: Main Library, Academy of Sciences of the Czech Republic
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    My satellite home page: http://www.lib.cas.cz/www/space.40/index.html
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