As a service to the satellite user community, the following description of the
NORAD two-line orbital element set format is provided for the NOAA NESDIS WWW
server. The most current orbital elements from the NORAD two-line element sets
are carried on the Celestial web site and Celestial BBS, (334) 409-9280, and are updated
daily (when possible). Documentation and tracking software are also available on this
system. The Celestial BBS may be accessed 24 hours/day at speeds up to 28,800
bps using 8 data bits, 1 stop bit, no parity. In addition, element sets
(also updated daily) and some documentation and software are available via
anonymous ftp from archive.afit.af.mil (129.92.1.66) in the directory pub/space.
==============================================================================
Data for each satellite consists of three lines in the following format:
AAAAAAAAAAAAAAAAAAAAAA
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 twenty-two-character name (this change is being made 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:
Line 1
Column Description
01-01 Line Number of Element Data
03-07 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)
63-63 Ephemeris type
65-68 Element number
69-69 Check Sum (Modulo 10)
(Letters, blanks, periods, plus signs = 0; minus signs = 1)
Line 2
Column Description
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 [Revs per day]
64-68 Revolution number at epoch [Revs]
69-69 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