Re: ISS decay?

From: Allen Thomson (thomsona@flash.net)
Date: Sat Apr 17 2004 - 13:30:06 EDT

  • Next message: Robert Holdsworth: "Re: Gravity Probe search orbit"

    > According to my program and present ISS tle (2004-04-16 11:52:19Z), I get
    04 Nov 2005 16:54:03 UT. That would be ± a day or two!
    
    Thanks, that agrees pretty well with Mr. Heger's value.
    
    I assume that both your and his projections are for natural, unboosted
    decay?
    
    BTW, I did a quick exercise with dividers on the Heavens Above ISS altitude
    chart and came up with rough numbers that may help characterize the period
    from mid-April 2003 to mid-April 2004.  In that time, the actual decrease in
    mean altitude ("height") was about 30 km.  During that time, there were four
    reboosts that raised the height by a total of about 11 km -- in other words,
    the total natural decay was about 41 km, and reboosts made up 11 km of that.
    Another measure is how much time was bought by the reboosts. For each
    reboost, I measured the approximate time it took for the height to decay to
    its pre-reboost value. Adding those up, it came to 13 weeks; since the
    overall decay curve is approximately linear over the one-year period
    covered, that's what you'd expect, of course: 11/41 ~= 13/52.
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Sat Apr 17 2004 - 13:34:42 EDT