Data for each satellite consists of three lines in the following format:

AAAAAAAAAAAAAAAAAAAAAAAA
1 NNNNNU NNNNNAAA NNNNN.NNNNNNNN +.NNNNNNNN +NNNNN-N +NNNNN-N N NNNNN
2 NNNNN NNN.NNNN NNN.NNNN NNNNNNN NNN.NNNN NNN.NNNN NN.NNNNNNNNNNNNNN

Example:

NOAA 14                 
1 23455U 94089A   97320.90946019  .00000140  00000-0  10191-3 0  2621
2 23455  99.0090 272.6745 0008546 223.1686 136.8816 14.11711747148495

Line 0 is a twenty-four character name (to be consistent with the name length in the NORAD SATCAT).

Lines 1 and 2 are the standard Two-Line Orbital Element Set Format identical to that used by NORAD and NASA. The format description is as follows:

Line 1
Column Description Example
01 Line Number of Element Data [1]
03-07 Satellite Number [23455]
08 Classification (U=Unclassified) [U]
10-11 International Designator (Last two digits of launch year) [94]
12-14 International Designator (Launch number of the year) [089]
15-17 International Designator (Piece of the launch) [A]
19-20 Epoch Year (Last two digits of year) [97]
21-32 Epoch (Day of the year and fractional portion of the day) [320.90946019]
34-43 First Time Derivative of the Mean Motion, revolutions per day [ .00000140]
45-52 Second Time Derivative of Mean Motion (decimal point assumed) [ 00000-0]
54-61 BSTAR drag term (decimal point assumed) for GP4 peturbations
(otherwise radiation pressure coefficient)
[ 10191-3]
63 Ephemeris type [0]
65-68 Element number [ 262]
69 Checksum (Modulo 10)
(Letters, blanks, periods, plus signs = 0; minus signs = 1)
[1]
Line 2
Column Description Example
01 Line Number of Element Data [2]
03-07 Satellite Number [23455]
09-16 Inclination (degrees) [ 99.0090]
18-25 Right Ascension of the Ascending Node (degrees) [272.6745]
27-33 Eccentricity (decimal point assumed at beginning) [0008546]
35-42 Argument of Perigee (degrees) [223.1686]
44-51 Mean Anomaly (degrees) [136.8816]
53-63 Mean Motion (revs per day) [14.11711747]
64-68 Revolution number at epoch (revs) [14849]
69 Checksum (modulo 10) [5]

All other columns are blank or fixed.

For further information, see "Frequently Asked Questions: Two-Line Element Set Format" in the Computers & Satellites column of Satellite Times, Volume 4 Number 3.

This is a edited local copy of a document originally produced by:

Dr TS Kelso [TS.Kelso@celestrak.com]
Last updated: 2000 December 30 02:37 EST


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