Yes, it is. Accuracy becomes much better as one gets update TLEs and
decay time gets closer.
Denis
Allen Thomson wrote:
>>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.
>
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