Where and how to get the orbital parameters (Two-Line Element) of a satellite over a period of time? -NORAD tutorial-

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What is a TLE? -short intro-

A TLE (two-line element set) is a two-line text containing information about the movement of an object in orbit around the Earth at a given time (noted “epoch”). It looks like this:

 ISS (ZARYA) 
 1 25544U 98067A 14273.50403866 .00012237 00000–0 21631–3 0 1790
 2 25544 51.6467 297.5710 0002045 126.1182 27.2142 15.50748592907666

On line 0 we have the object’s name. Lines 1 and 2 are the payload of the TLE. Here are the elements given in a TLE :

source : NASA

You can click on this link to see more details about TLE’s composition.

Where to find free TLE files?

You can find free, near-real-time TLE files on the NORAD website (click on this link), for example by choosing the TLEs of satellites launched in the last 30 days as in the following image:

Source : NORAD

However if you want to get the TLEs of a specific satellite and you can’t find it on the home page, you can make a special request by going to this link or by clicking on => TLE Data => Special Data Request, then by filling in all the boxes with your full name, and your email address (so that the site sends you the TLE file as a . txt file) and then the NORAD catalog numbers of the desired satellite (I explain afterwards how to get it) as well as the start and end dates (the epochs).

You are now on this page:

Source : NORAD

You can obtain NORAD catalog numbers by clicking on the link on the previous page : Online Satellite Catalog or by clicking on this link. You will then arrive here :

Source: NORAD

Then you can specify the name of the satellite you want to study -here I wrote down ZARYA- and specify the maximum number of responses you want. You can disable the filters before submitting your query.

Source : NORAD

Finally, you just have to choose the file to receive by e-mail, and to type in its NORAD Catalog Number in the second column -I have only one file, so I type in the number 25544-.
Then I just have to choose the start and end date (yyyy-mm-dd) and put everything in the previous page, like this :

Source : NORAD

Then click on Submit and you will receive the file on your email address. It should look like this :

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Note that the line “0” of the TLE giving the name of the satellite does not appear.

That’s the end of that tutorial! I hope you found it useful :)

A little tutorial on how to extract Cartesian information from a TLE with python:

Get the Cartesian position & velocity vectors of a satellite at a given time from a TLE (Two-Line Element) with python