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||8||21–32||[[Epoch (astronomy)|Epoch]] (day of the year and fractional portion of the day)||264.51782528
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||9||34–43||First derivative of [[mean motion]]; the ballistic coefficient (rev/day, per day)<ref name="nasahelp">{{cite web|url=http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/tle_def.html|archive-url=https://web.archive.org/web/20000301052035/http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/tle_def.html|url-status=dead|archive-date=1 March 2000|title=NASA, ''Definition of Two-line Element Set Coordinate System''|publisher=Spaceflight.nasa.gov|access-date=28 November 2014}}</ref>||-.00002182
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||10||45–52||Second derivative of [[mean motion]] (rev/day³, decimal point assumed)<ref name="nasahelp" />||00000-0
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||11||54–61||[[BSTAR|''B''*]], the drag term, or radiation pressure coefficient (units of 1/(Earth radii), decimal point assumed)<ref name="nasahelp"/>||-11606-4
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||12||63||Ephemeris type (always zero; only used in undistributed TLE data)<ref>{{Cite web|url=https://celestrak.com/columns/v04n03/|title=CelesTrak: "FAQs: Two-Line Element Set Format" |first=T. S. |last=Kelso |website=celestrak.com|access-date=2019-09-03}}</ref>||0
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||3||09–16||[[Orbital inclination|Inclination]] (degrees)||51.6416
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||4||18–25||[[Right ascension of the ascending node]] (degrees), in the [[Earth-centered inertial|ECI reference frame]], measured from the [[vernal point]]||247.4627
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||5||27–33||[[Orbital eccentricity|Eccentricity]] (unitless, decimal point assumed)||0006703
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||6||35–42||[[Argument of perigee]] (degrees)||130.5360
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For a body in a typical [[low Earth orbit]], the accuracy that can be obtained with the SGP4 orbit model is on the order of 1 km within a few days of the epoch of the element set.<ref>{{cite web|last=Kelso |first=T.S.|title=Validation of SGP4 and IS-GPS-200D Against GPS Precision Ephemerides|quote=AAS paper 07-127, presented at the 17th AAS/AIAA Space Flight Mechanics Conference, Sedona, Arizona|date=29 January 2007|url=http://celestrak.com/publications/AAS/07-127/|publisher=Celestrak.com|access-date=28 November 2014}}</ref> The term "low orbit" may refer to either the altitude (minimal or global) or orbital period of the body. Historically, the SGP algorithms defines low orbit as an orbit of less than 225 minutes.
The activation of the [[Space Fence]] in 2020 resulted in a great increase in the number of objects being tracked as the Space Fence's [[S-band]] RADAR is more sensitive than the radars used by the [[Air Force Space Surveillance System]] that previously had generated the raw data used for TLEs.<ref name="CelesTrak"/> The increase in the number of objects tracked meant that [[Satellite Catalog Number]]s may no longer fit in the five-digit field available in traditional TLEs. A secondary cause for the increase in Satellite Catalog Numbers was the commercialization of space and break-up events and collisions that have created debris objects.<ref name="CelesTrak"/> Adaptations of the TLE were considered to extend the number of encodable Satellites within the TLE but instead a new format, the [[CCSDS]] OMM (Orbit Mean-Elements Message), started being used in 2020 that supports nine-digit Satellite Catalog Numbers. The legacy TLE format will continue to use five-digit Satellite Catalog Numbers.<ref name="CelesTrak">{{Cite web|title=CelesTrak: A New Way to Obtain GP Data|url=https://celestrak.com/NORAD/documentation/gp-data-formats.php|access-date=2020-07-29|website=celestrak.com}}</ref>
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