# Questions tagged [algorithms]

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### Is the "light-time" correction for the Moon's position in Meeus "Astronomical Algorithms" putting the Moon in inertial position or apparent position?

I'm looking at the second edition of Meeus's "Astronomical Algorithms," chapter 47, "Position of the Moon." At the bottom of page 337, right before getting into the actual formulae ...
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1 vote
110 views

### Is my code correct to get six Keplerian parameters?

Is my code correct to get six Keplerian parameters? ...
• 19
1 vote
120 views

### How does the Gpredict software algorithm track satellites?

I was wondering how Gpredict calculates the ground tracks, Lat, Long and elevation based on a ground station. If I understand correctly, Gpredict takes the values from a TLE (Two-Line Element) set, ...
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487 views

### Which method STK uses to compute Umbra or Penumbra time intervals?

someone knows in which way STK computes the eclipse times for a satellite? I use a Matlab code taken from D.Vallado's library (ALGORITHM 34) but even if I use a PVT provided by STK (1 sec time step) ...
• 315
121 views

### GMAT: What causes the error "ArrayTemplate error : dimension error"?

I have made various scripts that work with GMAT, but once in a while I get an "ArrayTemplate error : dimension error" error. I do not know what causes it, as in this case my script appears ...
• 339
1 vote
114 views

### Solar Sail mission

Sorry for my English. I'm not native speaker I would like your advice in solar sail mission simulation. The purpose is to compare results with results in Wolfram Mathematica. We have CubeSat with ...
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789 views

### Satellite Revisit Time Analysis

I am currently making up my mind about revisit analysis. I am searching for clever algorithms to implement this in Matlab. I want to define targets on Earth surface and get the revisit times for each ...
• 101
552 views

### Code to generate Sun-Earth L2 halo orbits for given epoch?

I am working on a GMAT script out of personal interest (not part of a job) that involves a spacecraft orbiting the Sun-Earth L2 point. I have found some orbital state vectors for the spacecraft that ...
• 339
59 views

### Please explain a way of calculation of Lagrange multiplier in algorithm of low thrust transfer

In David Vallado's book 'Fundamental of Astrodynamics and Applications', chapter 6.7. ("Continuous-Thrust Transfers") there is an algorithm #47: Low Thrust Transfer. In this algorithm a ...
326 views

### If the Voyagers' lowest playback speed is 7200 bits per second, how can it transmit to Earth at only 160 bps?

How to calculate data rate of Voyager 1? mention's Voyager's data rate is currently 160 bits per second, and clicking on a recent entry in the Voyager DSN Tracking Schedule on the Voyager Mission ...
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### Did the Voyager spacecraft use a Golay, a Reed-Solomon and/or a Hamming code for data transmission encoding for error correction? (Need clarification)

The now-famous answer to How is stacking oranges in 24 dimensions related to receiving and decoding signals from the Voyagers? is worth stopping now here and going back and reading first. Okay welcome ...
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### What Voyager spacecraft hardware performed transmitted data coding in such a complicated way? Did ground decoding use “a big monster filling a rack”?

The now-famous answer to How is stacking oranges in 24 dimensions related to receiving and decoding signals from the Voyagers? is worth stopping now here and going back and reading first. Okay welcome ...
• 149k
9k views

### How is stacking oranges in 24 dimensions related to receiving and decoding signals from the Voyagers?

I was listening to Sphere Packing Solved in Higher Dimensions; A Ukrainian mathematician has solved the centuries-old sphere-packing problem in dimensions eight and 24. and reading the transcript ...
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Following up on a previous question about the classification of periodic orbits, how can they be constructed, especially the planar Lyapunov family, around libration points $L_1$ and $L_2$? And how ...