[amsat-bb] Re: Satellites in collision

Franklin Antonio antonio at qualcomm.com
Fri Feb 13 08:43:32 PST 2009

At 03:27 AM 2/13/2009, Rich Dailey (gmail) wrote:
>*If* the controllers of the Iridium satellite could alter it's orbit 
>slightly, ...

There's a great article in the International Herald 
Tribune.  Unfortunately, IHT has also carried several other articles 
about the collision with similar titles, so the good one is hard to 
find.  Use this link.


This article discusses the "what did they know" aspect.  In fact it 
says so much that it is confusing.  First it says they did not know 
in advance.

"Iridium didn't have information prior to the collision to know that 
the collision would occur,"

Then it says they get 400 "conjunction reports" from "US Strategic 
Command Joint Space Operations Center" per week (ie a notification 
that an object will pass within 5 km of a satellite), implying that 
they suffer from information overload.

Then they say the reports aren't any good anyway.

"So the ability actually to do anything with all the information is 
pretty limited,"

"Even if we had a report of an impending direct collision, the error 
would be such that we might manoeuvre into a collision as well as 
move away from one,"

Congratulations to the author for pulling these quotes 
together.  Unfortunately, it still leaves the reader uncertain about 
what happened.

The first quote may be lawyer-speak.  After all, nobody tracks these 
objects well enough to "KNOW that the collision WOULD occur".  That 
isn't the same as being warned that a one ton satellite is going to 
whiz by within 5 km.

When the first fellow says "Iridium didn't have information prior", 
is he saying the DOD missed this one, or is he saying, as in the 
other quotes, that the conjunction reports aren't accurate enough to 
take action?  Could be either.

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