NOAA KLM User's Guide

Appendix A.6

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APPENDIX A.6: NASA Two Line Orbital Elements (TLE)

A description of the NASA prediction bulletin's two line, orbital element set format is explained in the following example.

Data for each satellite consists of three lines (two of which contain actual orbital elements) in the following format:

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

Line 0 is a twenty-two-character name. Lines 1 and 2 are the standard Two Line Orbital Element Set Format identical to that used by USSC (formerly NORAD) and NASA. The format is described in Table A.6-1.

Table A.6-1. Format of standard Two Line Orbital Element Set.
Column Description
Line 1
01-01 Line Number of Element Data
03-07 Satellite Number
10-11 International Designator (Last two digits of launch year). See Table A.6-2.
12-14 International Designator (Launch number of the year). See Table A.6-2.
15-17 International Designator (Piece of launch). See Table A.6- 2.
19-20 Epoch Year (Last two digits of year)
21-32 Epoch (Julian Day and fractional portion of the day)
34-43 First Time Derivative of the Mean Motion or Ballistic Coefficient (depending on ephemeris type)
45-52 Second Time Derivative of Mean Motion (decimal point assumed; blank if N/A)
54-61 BSTAR drag term if GP4 general perturbation theory was used. Otherwise, radiation pressure coefficient. (Decimal point assumed)
63-63 Ephemeris type
65-68 Element Number
69-69 Check Sum (Modulo 10)
Line 2
01-01 Line Number of Element Data
03-07 Satellite Number
09-16 Inclination (degrees)
18-25 Right Ascension of the Ascending Node (degrees)
27-33 Eccentricity (decimal point assumed)
35-42 Argument of Perigee (degrees)
44-51 Mean Anomaly (degrees)
53-63 Mean Motion (revolutions per day)
64-68 Revolution number at epoch (revolutions)
69-69 Check Sum (Modulo 10)
Note: All other columns are blank or fixed.

Table A.6-2. Definition of satellite ID and International designator.
Satellite name Satellite ID (USSC) International Designator (Launch year and day)
NOAA-1 04793 7Δ1Δ6
NOAA-2 06235 72Δ82
NOAA-3 06920 73Δ86
NOAA-4 07529 74Δ89
NOAA-5 09057 76Δ77
TIROS-N 11060 78096
NOAA-6 11416 79057
NOAA-7 12553 81059
NOAA-8 13923 83022
NOAA-9 15427 84123
NOAA-10 16969 86073
NOAA-11 19531 88089
NOAA-12 21263 91032
NOAA-13 22739 93050
NOAA-14 23455 94089
NOAA-15 25337 98133
NOAA-16 26536 00055
NOAA-17 27453 02032
NOAA-18 28654 05018
NOAA-19 33591 09005
MetOp-A 29499 06044
Δ indicates a blank


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