Re: fireball or reentry ... ?

Alan Pickup (
Fri, 20 Nov 1998 23:03:55 +0000

Markku Vanamo <> writes
>  Reading this list one might even ask if anyone has ever even witnessed
>a satellite to reenter the atmosphere.  I wouldn't mind if the regularly 
>posted decay list would contain the assumed location of reentries after 
>the actual decay times has been established.  Though it serves no purpose 
>I find that information being very interesting.

Yes, several re-entries have been observed though none (yet), I think,
as a result of my decay predictions. As for putting the assumed location
of re-entries in my SatEvo decay list, I prefer not. For only a few
objects do I hazard a guess as to the possible decay location, and for
most of these I report this in a "Decay watch" posting. As I explain in
my lists, the "actual" decay times are only my estimates based on the
final elsets. Even at best, these times are uncertain by several (15-30
minutes) during which time the object would cover quite a distance along
track. To quote a final longitude and latitude would usually be
misleading and would be quite impossible for most objects for which even
the decay orbits are uncertain. Be thankful for small mercies, however -
USSPACECOM are secretive about their analyses of the decay circumstances
and only go public with their estimate of the _date_ of decay :(

 Alan Pickup | COSPAR 2707:   55d53m48.7s N   3d11m51.2s W   156m asl
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