[FPSPACE] blowing up satellites in orbit

[David Woods]

Folks,

Keith Gottschalk posted an item recently about USA-193 and the resulting 
debris field.  I passed it along to Nick Johnson who is the Chief 
Scientist for orbital debris at JSC.  Nick provided some additional 
information that I can pass along to you about it.

Dave

-------- Original Message --------
Subject: 	RE: blowing up satellites in orbit
Date: 	Sun, 9 Mar 2008 17:33:05 -0600
From: 	Nicholas Johnson
To: 	David Woods <drwoods1 at earthlink.net>
References: 	<47D445F0.7050906 at earthlink.net>



Sure.  An update on the USA-193 debris:  as of this morning, 153 had 
been cataloged.  Some are down already, but other debris still in orbit 
are being tracked and might be cataloged soon.
 
Nick
 
------------------------------------------------------------------------
*From:* David Woods
*Sent:* Sun 3/9/2008 3:17 PM
*To:* Nicholas Johnson
*Subject:* RE: blowing up satellites in orbit

Nick,

Could I post this exchange to our discussion forum?  I think folks would 
find it of interest.  Thanks.

Dave

-------- Original Message --------
Subject: 	RE: blowing up satellites in orbit
Date: 	Sun, 9 Mar 2008 08:48:09 -0600
From: 	Nicholas Johnson
To: 	David Woods mailto:drwoods1 at earthlink.net
References: 	mailto:47D2E778.7050508 at earthlink.net, 
<FDCDA820-2DF6-4F28-9262-5A10A59F1E1A at mimectl>



Dave,
 
Upon further deliberation, I believe the writer might have merely gotten 
some facts wrong.  Here is the situation:
 
1. The US SSN is currently tracked more than 17,000 objects, of these a 
little more than 12,000 are officially cataloged.  This includes all 
operational spacecraft and all debris at all altitudes, primarily with 
sizes of 10 cm or more, although a small percentage are between 5 and 10 cm.
 
2. Debris from Fengyun-1C now numbers over 2600, with only a little more 
than 2300 of these officially cataloged.  Some of the Fengyun-1C debris 
are expected (subject to solar activity) to still be in orbit next 
century.  Using special radar observations, NASA estimates that the 1 cm 
and greater population is on the order of 150,000.
 
3. The number and size distribution of USA-193 is still not know with 
accuracy.  To my knowledge the greatest number of TLEs created (day 
after the event) was 360.  Estimates of the objects detectable by the 
SSN (> 5 cm) range as high as slightly over 2000.  However, considerable 
post-processing will be needed to verify this and to ascertain what the 
sizes were.  The vast majority of the debris are already down, and the 
very last trackable object should be down within about 6 months.  Total 
number of USA-193 debris cataloged as of Friday was 139.
 
Hope this helps.
 
Nick

-------- Original Message --------
Subject: 	blowing up satellites in orbit
Date: 	Sat, 08 Mar 2008 15:48:07 +0200
From: 	Keith Gottschalk <kgottschalk at uwc.ac.za>
To: 	David Woods <drwoods1 at earthlink.net>
References: 	<47D1547D.7050506 at earthlink.net>


Dear Dave & Nick,

     I was handed a photocopy of a speech given by some top U.S.G.
official to a seminar at John Logsdon's Space Policy Institute at GWU.
In it he alleged (I was typing from memory) that US radars had tracked
either 13 000 or 17 000 pieces of orbiting debris, & that computer
extrapolations projected about another 100 000 pieces too small to be
detected by U.S. radars. The US official also alleged that where some of
these debris pieces had been blown upwards, with a higher apogee, some of
them would remain in orbit until the 22nd century. 

     If you can't trace this in your country, I'll ask my source to let
me borrow his photocopy & get the US official's name, & other
bibliographic details.

with warm regards from our dreadful southern hemisphere heat waves (it's
another humid 30 C today)

Keith