Home : Satellite Observing

## Two-Line Element Format

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

AAAAAAAAAAA
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

Line 0 is a eleven-character name.

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:

Line 1

Column | Description |

1 | Line Number of Element Data |

3-7 | Satellite Number |

10-11 | International Designator (Last two digits of launch year) |

12-14 | International Designator (Launch number of the year) |

15-17 | International Designator (Piece of launch) |

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 | Ephemeris type |

65-68 | Element number |

69 | Check Sum (Modulo 10) (Letters, blanks,
periods, plus signs = 0; minus signs = 1) |

Line 2

Column | Description |

1 | Line Number of Element Data |

3-7 | Satellite Number |

9-16 | 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 [Revs per day] |

64-68 | Revolution number at epoch [Revs] |

69 | Check Sum (Modulo 10) |

All other columns are blank or fixed.

Example:

NOAA 6
1 11416U 86 50.28438588 0.00000140 67960-4 0 5293
2 11416 98.5105 69.3305 0012788 63.2828 296.9658 14.24899292346978