Linked Questions

15
votes
3answers
13k views

How can I plot a satellite's orbit in 3D from a TLE using Python and Skyfield?

I have obtained a Two Line Element (TLE) of a satellite in Earth orbit from Celestrak at https://www.celestrak.com/NORAD/elements/ and I would like to use it to calculate an orbit. How can I ...
12
votes
3answers
1k views

Why are Tiangong-1's Apogee and Perigee Graphs Wobbly?

The apogee and perigee graph of the Tiangong-1 space station, about to re-enter and break up Real Soon Now, is depicted in this graph (source: Wikipedia): Why are the graphs wobbly? Is it because the ...
8
votes
4answers
242 views

How do cubesat owners first find out their cubesat's initial trajectory? How do they point antennas at it before official TLEs start to appear?

When cubesats are first deployed it can sometimes take several days before they start appearing in official TLE distributions, and even then if many were deployed it may take a lot more work to decide ...
6
votes
3answers
694 views

Will the new "TLE format" be orbitally-mechanically better than traditional TLEs?

Celetrak's A New Way to Obtain GP Data (aka TLEs) by Dr. T.S. Kelso 2020 May 27 explains the arrival a new infoblob format that in several ways is "better" than the ancient TLE, and contains ...
3
votes
3answers
2k views

what does Check sum TLE mean?

I am doing a report on TLE's and I was looking up what the numbers mean. I found a very helpful site. See here: http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/...
5
votes
2answers
725 views

Sun-synchronous satellite orbit propagation

I'm trying to propagate the orbit of a sun-synchronous satellite. The initial data is defined by the TLE. The orbit of the satellite is controlled by the operator ...
5
votes
1answer
2k views

TLE SGP4 Coordinate Transformations

I am working on developing a user friendly SGP4 orbit propagator in C on a PIC24. I have extensively read Revisiting Spacetrack Report #3 and celestrak - there are a few outstanding questions I have....
3
votes
2answers
273 views

What is/was legacy TLE ephemeris type 2? (TLE, line 1, column 63)

Wikipedia's Two-Line Element Set entry for line 1, column 63 (1.12) says: Ephemeris type (internal use only - always zero in distributed TLE data)13 13Celestrak Frequently Asked Questions: Two-Line ...
2
votes
2answers
487 views

How to correctly make a fake, counter-propagating TLE?

In this answer I have said: Do not make FAKE TLEs! I would now like to make a fake TLE. Specifically I'd like to generate a counter-propagating "twin" of an orbit by flipping inclination by 180° ...
5
votes
1answer
1k views

Calculating J2 perturbations in cartesian coordinates?

I am an engineering student and we have taken upon a project that involves modelling the motion of earth satellites. So far we have a model that uses numerical symplectic integration to solve the ...
1
vote
1answer
836 views

SGP4: propagation initialization by state vector

I'm using the SGP4 model to propagate the orbit, initialized by TLE from celestrak.com ...
3
votes
1answer
141 views

Computing a new TLE following a delta-v impulse?

Is there some code or a library out there that can take orbital elements, add a known delta-v component and then compute a new TLE? I found this one https://apps.dtic.mil/dtic/tr/fulltext/u2/a289281....
2
votes
0answers
302 views