From: wdwells@nyx.cs.du.edu (David "Fuzzy" Wells)
Subject: Re: Orbital elements of junk in space wanted
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Sun, 24 Jan 93 06:06:24 GMT

>> something unknown that is not in the catalog..... 
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> found pieces that NORAD did not know about or had reported lost.
>                          ^^^^^^^^^^^^^^^^^^
> Russia (ex-USSR) ?
> Other known launching nation(s) (China, Japan, France, etc...) ?
> Unknown launching nation(s) ?
> Meteorites ?
> Little natural satellites ?
> High altitude physical phenomena ?
> Very high-flying secret aircraft ?
> Other ?
> Within the computer software analysing these events, is there some
> kind of filter eliminating the objects (if any) which disappear soon
> after being detected, or which don't obey strictly the laws of
> gravitation and/or atmospheric re-entry ?

J. Pharabod,  Thanks for writing.

[for the novice out there:  satellite: anything going around the earth, not
just your MTV comm-sat]

	95% of those "unknown" objects are cataloged as debris pieces.  We
do not have 24 hour coverage of every little piece up there, so if a debris
"event" (explosion, breakup, asat, whatever) occurs, unless a sensor is lucky
enough to catch it in the act, we get surprised on the next observation.  It
is quite exciting (for my group) when a rocket body we had been tracking for
X years goes missing and XX number of little satellites show up on the screen
in the same general orbit.  You ever try to reverse-engineer an explosion??
	Another type of "unknown" is the lost satellite or the administratively
decayed satellite.  Once a satellite gets below the 90min period mark and
atmospheric drag starts to become a factor, our software starts losing
satellites.  If anyone wants to figure out exactly how to model atmos. drag
for any given object, feel free to send us the code.
	For any elset to be "good", at least three observations are needed.
Make that "three observations that correlate to a single elset within our
tolerances".  If an elset comes out that seems good but doesn't correlate to
any known object, then that becomes a UCT (uncorrelated track) and gets
thrown into the back numbers of the satcat for more analysis until it can
be found reliably, can be given a name/origin and then find its way into
the 2XXXX numbers.
	Back to your questions:  We do what is called NFL (new foreign
launch) to find elsets on non-US launches.  Thus, those unknown pieces
have just as much chance of being ours as anybody elses.  And EVERYBODY who
makes a launch from earth is included...even if we didn't think they could.
Meteorites are possible...and DSP satellites can track them as they reenter,
but most are very short-lived and not really "orbitting".  High altitude
physical mysteries...sure, although I HIGHLY doubt it.  BTW, there are lots
of work-arounds for the Northern Lights, so they are no biggie.  If you can
fly an aircraft (even at LEO) then you need to talk to the NASP people and
quick!  Nope, no aircraft can fly where we look...save that really big white
and black jobbie with the giant doors and NASA scrawled alongside it.
	Oh, back to natural satellites...those are a teaser and one of the
big topics that our group is working on...

"Other?"
<warning...silly stuff ahead (UFO talk)>

	And for the computer software...if three or more obs line up, then
you have a track...realistic or not.  And yes, people have made claims of
tracking an object that ascended radially outward from the center of the 
planet, pausing occasionally.....but the latest person to make that claim
was tracking it more than 15 years ago and I have not heard of any other
claims that date later.  So, you UFO groupies can chew on that for a while.
(BTW, I have _NO_ more info on those incidents.....I have no interest in 
them and don't wish to pursue.....<ie: I have better things to do with my
time than to write stories for the tabloids>)  BTW, given the bugginess of
both the software and the sensors (even now, problems creep up), I would be
more apt to place blame on the equipment than to UFOs.
	
					Cheers,
							Fuzzy.

==============================================================================
_ __/|       | Lt. David "Fuzzy" Wells |"How do you know I'm mad?" said Alice.
\'o.O'       |    HQ AFSPACECOM/CNA    |    
=(___)=      |      "We do debris"     | "You must be," said the Cat, "or you 
   U  ...ack!| wdwells@esprit.uccs.edu |       wouldn't have come here."
==============================================================================
Newsgroups: sci.space