Cosmos 398 and the eccentricity error.

David Cottle (dcottle@ozemail.com.au)
Tue, 12 Dec 1995 08:31:46 +1100 (EST)

I have forwarded a message I released concerning the subject below.


Date: Tue, 12 Dec 1995 08:20:13 +1100 (EST)
X-Sender: dcottle@ozemail.com.au
To: "David H. Ransom" <rans7500@spacelink.msfc.nasa.gov>,
        Brent Parker <sysop@oig1.atsc.allied.com>,
        Paul Traufler <paul.traufler@pobox.tbe.com>,
        Ken Ernandes <70511.3107@compuserve.com>,
        Ken Ernandes <kene@fs.loral.com>,
        David Cottle <dcottle@ozemail.com.au>,
        Phillip Clark <psclark@dircon.co.uk>,
        Joel Runes <z005465B@bcfreenet.seflin.lib.fl.us>,
        Bjorn Gimle <bjorn.gimle@online.dextel.se>,
        Ted Molczan <molczan@neocom.ca>,
        "Thomas A.E. Andersen" <damec@inet.uni-c.dk>
From: David Cottle <dcottle@ozemail.com.au>
Subject: Re: OIG TLE Format Change?
Cc: STS TLE 2 -- Michael Bartlett <a-mbart@microsoft.com>,
        Paul Beckley <EQCC57A@prodigy.com>,
        Manfred Bester <manfred@sunspot.ssl.berkeley.edu>,
        Helge Blucher <hblucher@ja6.jsc.nasa.gov>,
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        Rodger Cliff <tpcliff@lims01.lerc.nasa.gov>,
        Neil Clifford <n.clifford1@physics.oxford.ac.uk>,
        David Cottle <dcottle@ozemail.com.au>,
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        "Catherine O. Young" <cqy4650@is.NYU.EDU>

Gentlemen,

Firstly my apologies for duplication, as a lot of you are on both the 
STS TLE 2 list and in this transmission. As this is important I 
forwarded it on the STS TLE 2 list as well.

I have seen the comments on the eccentricity of Cosmos 398 flying 
around everywhere, <Dave Ransom's message is attached below>. 

I am sure its just a typo or a over looked error. Since the epoch time 
after the bad TLE, I have made two postings of TLE's on Cosmos 398 
and did not have to manually correct the eccentricity.

Here the are later EPOCHS I released as directly taken from OIG's TLE 
catalog ;

1 04966U 71016A   95343.47645446  .03571883  12427-4  13821-3 0  1696
2 04966  51.3592  83.8343 006474   23.9304 336.4721 16.33662038852204

1 04966U 71016A   95344.69514904  .14112176  13011-4  11508-3 0  1783
2 04966  51.3552  76.9050 002555   35.4339 324.8613 16.49944148852405

There is no error in these sets. Unfortunately my data released before 
this, coincides to the earlier EPOCH in which the error was not evident.

I am assuming its simply just a typo in the element set, and was not 
picked up by who ever released it / forwarded it.

Based on my later sets taken from OIG, I know its safe to assume my 
conclusion it was a error either on OIG, or when the element in question 
was re-distributed out.

I normally verify all my elements I send out <especially shuttle TLE's I 
generate>, but sometimes on the MIR and other sets, I just eyeball them 
to ensure there are no obvious errors in the structure or format and 
then release them.

Knowing USSPACECOM and its habit of errors popping up especially on REV 
numbers, and release set numbering.

It was only last week, Dave Ransom noticed the REV numbers out on MIR
substantially. I noticed release sets on MIR change drastically myself 
<see below>, both of these sets were taken from OIG, as you can see by 
the epochs, they are consecutive days, somehow MIR lost 27 sets in its 
numbering !!!.

1 16609U 86017A   95340.15801137 +.00002976 +00000-0 +45172-4 0 03778
2 16609 051.6464 016.2223 0003143 028.5839 331.5325 15.58219327459768

1 16609U 86017A   95341.31242010  .00000093  00000-0  77856-5 0  3500
2 16609  51.6472  10.4386 0003805  29.1457 330.9757 15.58212010459945


I think its a very good policy to eyeball sets, and like in this case 
would have saved a lot of problems for everyone.

Indeed if anyone else has some comments or conclusions, I also would 
love to hear them.

Hope this helps put some minds at ease...

Cheers,

Dave


        David Cottle    EMAIL : dcottle@ozemail.com.au
                        WWW   : http://www.ozemail.com.au

---------------------------------------------------------

At 08:48 AM 12/11/95 -0600, you wrote:
>Brent,
>
>The following TLEs were forwarded to me from Sweden for comment:
>
>Element set number = 1
>1 04966U 71016A   95342.25031658  .02196052  12186-4  13650-3 0  1631
>2 04966  51.3616  90.7090 0086588  18.5963 341.8171 16.26703743852000
>Element set number = 5
>1 04966U 71016A   95342.31174141  .02175073  12192-4  13586-3 0  1649
>2 04966  51.3605  90.3664 .008505  18.5150 341.9069 16.27007458852011
>                          ^^^^^^^
>                          ^^^^^^^
>
>Note the eccentricity marked above in "Element set number = 5" which 
>includes a decimal point. Does this represent a format change or is this 
>an anomaly in the data stream? Such a change would have widespread 
>negative impact on TLE processing programs.
>
>Please advise if you have any information and/or guidance!
>
>DAVE
>
>----------
>David H. Ransom, Jr.   Email:rans7500@spacelink.msfc.nasa.gov
>



--------------
		David Cottle
		IDB Communications.
		Sydney, Australia.
--------------
David Cottle -	Email Primary : dcottle@ozemail.com.au
		Email Backup  : 100354.450@compuserve.com
		W.W.W. Page   : http://www.ozemail.com.au/~dcottle/
.


--------------
		David Cottle
		IDB Communications.
		Sydney, Australia.
--------------
David Cottle -	Email Primary : dcottle@ozemail.com.au
		Email Backup  : 100354.450@compuserve.com
		W.W.W. Page   : http://www.ozemail.com.au/~dcottle/
.