Two Line Element Set Format
A Two Line Element Set or (TLE) is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time (epoch). Below is the designated format used by NASA and other organizations, as well as amateur satellite trackers to predict the orbital elements of a man made satellite.
1 xxxxxu xxxxxaaa xxxxx.xxxxxxxx +.xxxxxxxx +xxxxx-x +xxxxx-x x xxxxx
2 xxxxx xxx.xxxx xxx.xxxx xxxxxxx xxx.xxxx xxx.xxxx xx.xxxxxxxxxxxxxx
2 xxxxx xxx.xxxx xxx.xxxx xxxxxxx xxx.xxxx xxx.xxxx xx.xxxxxxxxxxxxxx
Example of a 2 line element set for the International Space Station:
1 25544U 98067A 18258.87806760 .00016717 00000-0 10270-3 0 9036
2 25544 51.6413 286.7600 0004466 162.8037 197.3268 15.53868139 12613
1 25544U 98067A 18258.87806760 .00016717 00000-0 10270-3 0 9036
2 25544 51.6413 286.7600 0004466 162.8037 197.3268 15.53868139 12613
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Column
|
Description
|
|
Line 1
|
Line number of element data
|
|
Lines 03 - 07
|
Satellite number
|
|
Lines 09 - 16
|
Inclination (degrees)
|
|
Lines 18 - 25
|
Right ascension of the ascending node
(degrees)
|
|
Lines 27 - 33
|
Eccentricity (decimal point assumed)
|
|
Lines 35 - 42
|
Argument of perigee (degrees)
|
|
Lines 44 - 51
|
Mean anomaly (degrees)
|
|
Lines 53 - 63
|
Mean motion (revolutions per day)
|
|
Lines 64 - 68
|
Revolution number at epoch (revolutions)
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|
Line 69
|
Checksum (modulo 10)
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| Column | Description |
| Line 1 | Line number of element data |
| Lines 03 - 07 | Satellite number |
| Lines 08 | Classification (U=unclassified) |
| Lines 10 - 11 |
International Designator (last two digits of launch year) |
| Lines 12 - 14 |
International Designator (launch number of the year) |
| Lines 15 - 17 | International Designator (piece of the launch) |
| Lines 19 - 20 | Epoch Year (las two digits of year) |
| Lines 21 - 32 |
Epoch (day of the year & fractional portion of day) |
| Lines 34 - 43 | First time derivative of the mean motion |
| Lines 45 - 52 |
Second time derivative of mean motion (decimal point assumed) |
| Lines 54 - 61 |
BSTAR drag term (decimal point assumed) |
| Line 63 | Ephemeris type |
| Lines 65 - 68 | Element number |
| Line 69 |
Checksum (Modulo 10) (Letter, blanks, periods, plus signs = 0; minus signs = 1) |
Line 1
Line 2