[meteorite-list] U.S. To Shoot Down Defunct Spy Satellite

[Sterling K. Webb]

Hi,

    While I agree the likelihood of meaningful debris is very
small, this NYTimes piece:
http://www.nytimes.com/2008/02/15/us/15satellite.html?em&ex=1203224400&en=2350567d2300e89b&ei=5087%0A
contains a prediction that a successful hit on USA-193 will
produce "100,000" pieces of new debris. I think that is a
complicated engineering question that was almost certainly
NOT evaluated by the person quoted, but I suppose it is
a possibility.

    Rob pointed out that only a very small percentage of the
debris will  be directed into potentially dangerous orbits, but
a "small percentage" of 100,000 is still a respectable number.

    The NYTimes piece contains further details of interest. The
three-ship flotilla tasked with the takedown will operate in the
North Pacific where, depending on the orbital inclination, a
stripe running "down orbit" could stretch around the planet
for a full orbit, down the Pacific, then across Antarctica, up
the Atlantic, over the Arctic, or as close to this ideal as can be
managed.

    I hope there's some attempt to derive as much data as
possible from this little adventure. The SM-3's return a lot of
data. There should be tracking ships "down the line," I would
think, to determine the progress of the breakup and to check
for big chunks. Since the Times article implies that there will
be only the one cruiser, it is unlikely that there will be more
than the one attempt.


Sterling K. Webb
------------------------------------------------------------------------
----- Original Message ----- 
From: "Chris Peterson" <clp at alumni.caltech.edu>
To: <Meteorite-list at meteoritecentral.com>
Sent: Friday, February 15, 2008 11:39 AM
Subject: Re: [meteorite-list] U.S. To Shoot Down Defunct Spy Satellite


> Surley fragmenting something this big, will mean it is actually more
> likely for [something] to survive?

I don't think so. Space debris reaches the ground when it is protected
by large structures around it. Break it up into small pieces, and it's
doubtful anything will survive. (While the official claim is that this
is being done to protect people from falling, toxic debris, I think we
all know better. It's being done so sensitive material doesn't end up
dropping someplace we have no control over.)

> ...since you will create random
> pieces of debris with very differing velocities and therefore some
> might
> have more chance of having suitable rentry parameters which will allow
> them to survive...

Probably not all that much variation in velocities.

> Either way - Really, this is not very good news for the low earth
> space
> environment!

This is the _really_ low earth environment- only marginally "space" at
all. While I suppose it's possible that a very few pieces could end up
in higher orbits, on the whole there's nowhere near enough energy being
delivered to have much effect on the average orbit. Breaking this
satellite up into small pieces is just going to increase individual
decay rates. Within a matter of days, the vast majority (if not all) of
the junk is going to be gone. What the Chinese did last year was
irresponsible, but destroying this satellite isn't going to produce any
debris that we have to worry about.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Mark Ford" <mark.ford at ssl.gb.com>
To: <Meteorite-list at meteoritecentral.com>
Sent: Friday, February 15, 2008 2:00 AM
Subject: Re: [meteorite-list] U.S. To Shoot Down Defunct Spy Satellite


> Hmmm.
>
> Looks like we are in for an even better firework display now then!
>
> Surley fragmenting something this big, will mean it is actually more
> likely for [something] to survive? -  since you will create random
> pieces of debris with very differing velocities and therefore some
> might
> have more chance of having suitable rentry parameters which will allow
> them to survive...
>
> Either way - Really, this is not very good news for the low earth
> space
> environment!
>
> About time we had some proper global treaties in place to stop
> countries
> randomly polluting space, all for the sake of some commercial secrets
> (which are already probably common knowledge anyway).
>
> Best,
> Mark Ford

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