Questions tagged [astrodynamics]

The study of satellite orbits and space flight dynamics.

128 questions
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Why are uncertainties of orbital state vectors provided as covariance matrixes?

I have recently become interested in testing a numerical orbital propagator with ISS ephemerides, following @RyanC's suggestion in this answer. Ephemerides for the ISS seem to be publicly available in a format known as OEM (Orbital Ephemeris…
Rafa
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1 answer

Why is there a singularity in Lambert solutions for transfers of pi-multiple degrees?

Lambert provides a solution as long as the transfer angle is not 0, 180 or 180-multiple degrees. Why is that?
Paek Se
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5
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1 answer

How to implement a relative motion STM without any numerical integration

I am trying to program the Gim-Alfriend state transition matrix. You can read all about it here. The GA STM is a complex analytical model that maps relative motion of a deputy satellite in a curvilinear frame centered at a chief satellite. It is…
3
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1 answer

What is the amount of Delta-V required to enter lunar orbit following Trans-Lunar Injection?

How much do you need to decelerate in order to be captured into a stable lunar orbit from a Trans-Lunar Ejection or TLI-type trajectory?
TeslaK20
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Working out time spent by spacecraft above certain latitudes

I'm currently working through some practice exercises and one is about how many minutes per orbit a spacecraft spends above a certain latitude. How can this be calculated? I can't find any equations and visualising the problem using GMAT hasn't…
1
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2 answers

Properly calculating G-factor

This may sound rather simple, but I was told that technically, G-force readout should actually indicate zero-G on the earth's surface, as well as in a stable orbit. This is due to the fact that G-force is measured using accelerometers (which measure…
Mitch99
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