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@amsat.org wrote:

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Message: 4 Date: Mon, 29 Nov 2010 22:55:16 +0100 From: PA3GUOpa3guo@upcmail.nl Subject: [amsat-bb] O/OREOS TLE errors ? To:amsat-bb@amsat.org Message-ID:19767175.1291067716437.JavaMail.root@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