Linked Questions

4 votes
1 answer
166 views

What is the current state of the art in converting between mean and osculating orbital elements?

I want to implement algorithms to convert from mean to osculating elements, and vice versa. I've been digging through Vallado's text (fourth edition), and under ...
Danny's user avatar
  • 215
7 votes
2 answers
568 views

For any state vector of a satellite at an arbitrary time T1, is there another state vector at a given time T2 that will result in the same orbit?

I recently found the question In a 3D space defined by semimajor axis, eccentricity and inclination, what would be the shape of the space where SDP4 works better than SGP4? and have become interested ...
Rafa's user avatar
  • 1,750
7 votes
1 answer
270 views

Textbook or scholarly discussion of equations used by the SDP4 part of SGP4 TLE propagators beyond Space Track Report #1?

(the famous) Space Tract Report #3 discussed at length in Dr. T.S. Kelso's Revisiting Spacetrack Report #3, AIAA 2006-6753 Describes the "deep space" corrections to the original SGP4 known ...
uhoh's user avatar
  • 149k
5 votes
2 answers
343 views

In a 3D space defined by semimajor axis, eccentricity and inclination, what would be the shape of the space where SDP4 works better than SGP4?

@BillGray's answer to Why can't custom-made TLEs for the DSCOVR launch booster in orbit around Earth work with SDP4? is quite interesting and informative; I fail to do it justice by summarizing it as ...
uhoh's user avatar
  • 149k
8 votes
2 answers
434 views

How to calculate the very special orbit of 2020 SO

From a NASA JPL page: Earth May Have Captured a 1960s-Era Rocket Booster Source (Sorry, I got an error when I tried to include an animated gif.) 2020 SO was captured by Earth's gravity on Nov. 8, ...
Uwe's user avatar
  • 49k
2 votes
1 answer
170 views

Why can't custom-made TLEs for the DSCOVR launch booster in orbit around Earth work with SDP4?

This fascinating answer to Why has no TLE been published for the DSCOVR satellite and the Falcon 9 R/B? presents links to custom-made TLEs for the Falcon 9 rocket body that put DSCOVR into orbit, and ...
uhoh's user avatar
  • 149k
5 votes
1 answer
769 views

Get dates when a satellite has performed maneuver from historical TLE data (python)?

I have been recently acquainted with orbital mechanics and am trying to do some analysis on the subject. Since I don't have subject matter expertise, I am at a crossroads with trying to decide that ...
aashay shah's user avatar
3 votes
1 answer
809 views

Confused about SGP4 implementation published by celestrack

I was trying to understand how SGP4 computes the propagated position I had a look on the original publication paper but i have not found a satisfactory answer. So I had a look to the Matlab ...
Giacomo Curzi's user avatar
5 votes
1 answer
851 views

How can Earth-Centered Inertial (ECI) coordinates be properly called "inertial" if the Earth's orbit is always accelerating towards the Sun?

I've just realized (again) that I don't understand anything, something that often happens to me after reading a @DavidHammen answer. How can Earth-Centered Inertial (ECI) coordinates be inertial if ...
uhoh's user avatar
  • 149k
4 votes
2 answers
426 views

SGP4 on Systems Tool Kit (STK); how to check if SDP4 deep space correction is implemented?

I am doing orbit propagation for a geostationary satellite which requires the deep space corrections of SDP4. See my previous question SGP 4 for Geostationary Satellite. I am using SGP4 on STK, but, ...
Elisa Fitri's user avatar
7 votes
1 answer
417 views

SGP 4 for Geostationary Satellite

I have read some sources that say that SGP4 is for satellite which have orbital period less than 225 minutes. For orbital period more than 225 minutes, we should use SDP4 instead. I need a ...
Elisa Fitri's user avatar
4 votes
3 answers
1k views

Is the amount of accurate information in a TLE equal to that of a single state vector?

My question is basically regarding whether there is orbital information "lost" when converting from a Two Line Element set (TLE) to a state vector. Given that the following are true: I have a TLE, ...
botsby's user avatar
  • 43
3 votes
2 answers
343 views

When calculating the future orbit of an artificial Earth satellite, is the Moon's gravity significant or insignificant?

Imagine a mathematician is plotting the future orbit of a satellite to be launched and put in orbit around the Earth. When they are making their calculation, is the moon so far away and the ...
hawkeye's user avatar
  • 359
6 votes
1 answer
333 views

Is TESS really lost? What does Celestrak mean exactly?

From this answer to the question What artificial satellite has the farthest orbit around the Earth?: I found the following "far out" spacecraft: TESS (Transiting Exoplanet Survey Satellite)...
uhoh's user avatar
  • 149k
1 vote
0 answers
381 views

Cis-L2 Libration Point Halo Orbit

Queqiao became the first satellite to orbit the Cis-L2 libration point (far side of the moon). Link: https://en.wikipedia.org/wiki/Chang%27e_4 Does anyone have any insight on how to model this orbit ...
Ari Stern's user avatar

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