Questions tagged [orbital-motion]
The path a body takes while moving through space under the influence of the gravitational forces of other bodies
2,638 questions
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Transforming Initial Cartesian Uncertainty into Delaunay Variables for Orbital Uncertainty Propagation [closed]
I am working on orbital uncertainty propagation where the initial uncertainty is given in Cartesian coordinates ( 𝑟 , 𝑣 ) (r,v), either as a covariance matrix or as bounded (non-statistical) ...
2 votes
1 answer
73 views
Why does orbital velocity variation correlate with $\sin$ of the angle between position and velocity vectors?
By analyzing the motion of Venus using NASA JPL Horizons ephemeris data (10-year span, 1-hour sampling), I found that the variation of orbital velocity $\Delta v(t)$ appears to closely follow a ...
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2 votes
1 answer
236 views
Orbiting ring vs orbiting body
A solid ring cannot orbit a mass at its center because it is in unstable equilibrium, and a slight perturbation would cause it to drift. An object obviously can orbit. You can also take a portion of a ...
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2 votes
1 answer
60 views
How to minimise jettisoned mass spent for a body with continuous but variable thrust?
In general I would like to know how to minimise fuel mass spent for an orbiting body that continuously jettisons its mass (i.e. ion thruster) so as to perform efficient transfer maneuver in ...
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Could cometary non-gravitational acceleration be linked to surface cohesion transitions?
In several comets, including the interstellar comet 3I/ATLAS, a non-gravitational acceleration is observed, i.e., a net thrust not fully accounted for by gravity. While outgassing is known to produce ...
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1 vote
1 answer
114 views
Can a position dependent mass term in the Klein–Gordon equation cause apparent orbital motion of wave packets?
The Klein–Gordon equation with a position-dependent effective mass, $$ \frac{\partial^2 E}{\partial t^2} = c^2 \nabla^2 E - \chi(x)^2 E, $$ describes a scalar field whose local propagation speed ...
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1 vote
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73 views
Deriving the Orbit Equation
I would like to understand the derivation of the orbit equation. I am following the derivation at https://orbital-mechanics.space/the-orbit-equation/the-orbit-equation.html which is largely ...
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4 votes
4 answers
486 views
On the meaning of the radial coordinate in the simplification of the Two-Body Problem. Inertial or non-inertial reference frame?
When presented with the two-body problems, we usually start from Newton's 2nd equations for the two bodies: $$ \begin{split} m_1 \mathbf{\ddot{r}}_1 &= f(r) \mathbf{\hat{r}}, \\ m_2 \mathbf{\ddot{...
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2 votes
1 answer
220 views
Are stable circular orbits for neutrinos possible at radii between the photon sphere and the Innermost Stable Circular Orbit (ISCO)?
For a non-spinning (Schwarzschild) black hole: The event horizon (Schwarzschild radius) is at: $$r = \frac{2GM}{c^2}$$ Inside this radius, not even light can escape. Outside that, there is the ...
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0 votes
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Is general relativity required to calculate to orbits of Pluto's moons? How to calculate of orbits of the Pluto's moons?
Is general relativity required to calculate to orbits of Pluto's moons? How to calculate of orbits of the Pluto's moons?
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1 vote
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Coriolis Force on a Phobos anchored Sarmont tether [closed]
One of my daydreams is a non rotating sky hook anchored on Phobos. I was wondering how to calculate the Coriolis Force induced by ascending or descending elevator cars. Wikipedia tells me: Coriolis ...
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Is there a site that I can used to make API requests for the positions of the planets in the solar systems? [duplicate]
I am creating a program that calculates orbital mechanics. And one option I want is the ability to use as a starting point the current positions of the Solar System. So is there a site that can I use ...
0 votes
1 answer
73 views
Correcting the angular momentum in GR for non-point-like bodies?
Background Consider I'm studying the orbit of planets using the Schwarzschild metric is given by: $$ ds^2 = -\left(1 - \frac{2GM}{c^2 r}\right) c^2 dt^2 + \left(1 - \frac{2GM}{c^2 r}\right)^{-1} dr^2 +...
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1 vote
1 answer
295 views
NASA defying physics or what's wrong with Earth flybys [closed]
Imagine a space probe that starts around Earth at time $t=0$ with velocity $\vec{V_0}$ (sun reference frame) and goes into an elliptical orbit around the sun such that after (almost) exactly one year ...
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1 vote
1 answer
195 views
Periods of a spherical pendulum
I can find articles deriving the motion equations, by conservation of angular momentum, etc. An example https://en.wikipedia.org/wiki/Spherical_pendulum But none discuss the solutions themselves (...
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