# Loading satellite TLE data into MATLAB using satellite function

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John Nolan on 18 Jul 2024 at 17:55
Commented: Umar on 24 Jul 2024 at 6:29
Using TLE data from an online database, MATLAB throws the error "The specified initial conditions will cause the orbit of 'STARLINK-2438' to intersect the Earth's surface." when using this function:
clc
clearvars
close all
format long
G = 3.986004418e14;
% Create a satellite scenario and add ground stations from latitudes and longitudes.
startTime = datetime(2024,7,18,13,00,41);
stopTime = startTime + days(1);
sampleTime = 60*1;
sc = satelliteScenario(startTime,stopTime,sampleTime);
sat = satellite(sc,'test_tle.txt')
The TLE data in "test_tle.txt" is as follows:
STARLINK-2438
1 48103U 21027M 24199.52200852 .27610719 12343-4 29456-2 0 9995
2 48103 53.0228 234.3624 0004658 334.7729 174.1970 16.36724891183121
when manually importing the values into the function, I dont receive the error:
% Mean Motion Line2 Field 8
semiMajorAxis = (G)^(1/3)/((2*pi*(16.36724891183121)/86400)^(2/3)); % ref : https://space.stackexchange.com/questions/18289/how-to-get-semi-major-axis-from-tle
% Eccentricity Line2 Field 5
eccentricity = 0.0004658;
% Inclination Line2 Field 3
inclination = 53.0228;
% Right Ascension of the asending node Line2 Field 4
rightAscensionOfAscendingNode = 234.3624;
% Argument of perigee Line2 Field 6
argumentOfPeriapsis = 334.7729;
% Mean Anomaly Line2 Field 7
trueAnomaly = 174.1970;
sat = satellite(sc,semiMajorAxis,eccentricity,inclination, ...
rightAscensionOfAscendingNode,argumentOfPeriapsis,trueAnomaly);
##### 5 CommentsShow 3 older commentsHide 3 older comments
sun on 24 Jul 2024 at 5:08
Yes, I am the same way. The data running in the code is official data obtained from the official website. Removing the erroneous part of the code can run normally, but obviously this processing method is unreasonable.
Umar on 24 Jul 2024 at 6:29
@sun, could you please suggest a better processing method?

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### Accepted Answer

Sam Chak on 22 Jul 2024 at 19:25
Moved: Sam Chak on 22 Jul 2024 at 20:26
It had de-orbited about a few days ago. Perhaps the final TLE data suggested that it reentered Earth's atmosphere.
##### 3 CommentsShow 1 older commentHide 1 older comment
John Nolan on 22 Jul 2024 at 22:48
why would it matter though whether I use the Keplerian elements (ie semiMajorAxis, eccentricity etc) explicitly versus using the text file version of the function? I guess that is still an open question. could it be that the calculations for the orbit are slightly different which can trigger the trajectory into earths atmosphere when using one method vs the other?
Umar on 23 Jul 2024 at 1:17
Hi John,
While both explicit usage of Keplerian elements and text file versions serve as valid methods for orbit calculations, understanding their differences and potential impacts on trajectory predictions is crucial for ensuring accuracy and reliability in orbital simulations. Further exploration and testing may help elucidate any nuances or effects that arise from choosing one method over the other.

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