[amsat-bb] Re: O/OREOS TLE errors ?

Ryan Caron rcaron at gmail.com
Sun Dec 26 11:29:28 PST 2010

Hank (and the -bb)

Attached is the spreadsheet previously mentioned spreadsheet to fix TLEs 
checksums. I've rewritten it since what I was using was still a tedious 
operation and I didn't want to distribute that to the community. This 
should be much better, though you still need to remove any leading 
spaces in the lines.

It appears that O/OREOS' TLEs on their website are OK now, possibly 
because SpaceTrack is publishing now. My apologies for not getting this 
out sooner; we'll have to wait for the next launch to try this out.

During the fog-of-war in the days after launch, I find there are often 
multiple TLEs for the same satellite. In this case I like to change the 
IDs so I can have them all loaded in GPredict simultaneously. This 
spreadsheet will verify that the IDs are the same for both lines, and of 
course regenerate the checksums.

This spreadsheet was created with OpenOffice 3.2.1, and I've exported it 
to Excel and checked it with MS Office XP and appears to work fine. 
Please let me know if there are any problems.

Happy holidays and 73,

On 11/30/10 11:33 AM, PA3GUO wrote:
> Hi Ryan
> Thanks a lot for your detailed reply.
> Would you be so kind to share that spreadsheet (XLS?) with me ?
> In the coming days I really need (well, would higly appreciate) to
> have working TLEs - especially also for Nanosail.
> Best of course would be if the O/OREOS/Nanasail team could fix this prior
> to posting them on the web :-)
> Thanks
> Henk
> ---- Ryan Caron<rcaron at gmail.com>  schreef:
>> The O/OREOS TLEs consistently do not have valid checksums (last digit of
>> each line). I submitted a comment about this on their website but I have
>> not heard back. The correct checksums are 2&  3, and not the 6&  5 that
>> is listed.
>> If, by the time you read this, the posted TLEs are not 6&  5, then the
>> TLEs have been updated and you'll have to generate new checksums. The
>> formula is a sum of all numerical characters on the line, including the
>> line number, treating minus signs as a one and everything else (letters,
>> +, spaces) as a 0. Then take modulus 10 of the sum (i.e. last digit of
>> the sum). Look it up on wikipedia for more details.
>> I've made a spreadsheet to fix this, but it is still a manual operation
>> for me (got to write a script at some point). Some programs disregard
>> the the checksum, which is why HRD&  the website still work and your
>> tracking tool doesn't. Predict/GPredict, my tools of choice, require
>> valid checksums, making proper TLEs a pet peeve of mine. I don't know
>> what NOVA's up to.
>> In terms of "swarm spread" (i.e. how small delta-V between spacecraft
>> that shared the same ride, which in this case is just done by compressed
>> springs, translates into spatial differences), 35 minutes of separation
>> is pretty high for just 10 days after launch. With all the latest TLEs
>> from the three websites, I show O/OREOS being 3.5 minutes ahead of RAX,
>> and RAX being a 1.33 minutes ahead of FAST1/2.
>> Ryan, KB1LKI
>> On 11/30/10 4:54 AM, amsat-bb-request at amsat.org wrote:
>>> ------------------------------
>>> Message: 4
>>> Date: Mon, 29 Nov 2010 22:55:16 +0100
>>> From: PA3GUO<pa3guo at upcmail.nl>
>>> Subject: [amsat-bb]  O/OREOS TLE errors ?
>>> To:amsat-bb at amsat.org
>>> Message-ID:<19767175.1291067716437.JavaMail.root at viefep21.chello.at>
>>> Content-Type: text/plain; charset=utf-8
>>> Dear all,
>>> I keep on having troubles with the O/OREOS kepler sets.
>>> RAX and the others are fine.
>>> With todays version (as from the O/OREOS dashboard on the web)
>>> - NOVA gives O/OREOS just a bit behind RAX
>>> - HamRadioDeluxe give O/OREOS 35 minutes behind RAX
>>> - The O/OREOS web (dashboard graphic) shows O/OREOS 35 minutes behind RAX
>>> - My private antenna tracking tool does not recognize the keplerset of O/OREOS
>>> Anyone else has experienced this (and maybe even a solution) ?
>>> Henk
>>> --
>>> Henk, PA3GUO
> --
> Henk, PA3GUO

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