Loading satellite TLE data into MATLAB using satellite function

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);

[Umar]

Hi John,

I wanted to help you out. In the attached screenshot, it displays an error but ignore that. Try passing the data in your code as shown in attached and execute the code, tell me what happened. The reason I am asking is because txt file formatting might have to do something with your code.

[sun]

I have the same problem and I don't know if the blogger has already solved it?

[John Nolan]

The text files are taken directly from a online database. Whats strange is that only some of the satellites in the textfile trigger the error, not all of them do it.

[sun]

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]

@sun, could you please suggest a better processing method?

Answer 1

[Sam Chak]

It had de-orbited about a few days ago. Perhaps the final TLE data suggested that it reentered Earth's atmosphere.

[John Nolan]

Ohhh wow. That makes sense. Never considered that. Thanks Sam!

[John Nolan]

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]

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.