# Tag Info

### What is the time dilation between Mars and Earth resulting from the mass difference?

From my answer to Parker Solar Probe passing extremely close to the Sun; what relativistic effects will it experience and how large will they be?: From here (or here if you are ambitious) the lowest ...
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### How I can find the angular orbital velocity of satellite in circle orbit?

per Kepler's third law The ratio of the square of an object's orbital period with the cube of the semi-major axis of its orbit is the same for all objects orbiting the same primary. You've specified ...
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### "Pythagorean Three Body Problem" - need some points from an accurate solution for comparison

I just ran it, and mine look pretty much like those in the paper. See some coordinates at the bottom. Here are some {x,y} coordinates at the times in the left column: ...
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### How to get true anomaly from time?

edit: @DavidHammen has just posted a much more thorough and insightful answer, which also points out some problems applying Newton's method to the current form. I'm pretty sure there are has never ...
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### What is this perturbation effect called, and what would be an analytical expression for the resulting eccentricity oscillations?

As the comments on the original question have stated, this is due to the spherical harmonics of the Earth. This answer is adding more context. In the two-body problem, one assumes that the central ...
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### How to calculate position of GPS Satellite with transmitted ephemeris data?

You can find a C++ method contained in the source code of Andrew Holme homemade GPS receiver project. The method is called GetXYZ and is the EPHEM (ephemeris) namespace and looks as the following: <...
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### How fast would one have to move to achieve permanent lunar day by perpetually moving along with the solar terminator?

A more generic answer could be: Angular speed (constant in any point on surface) is $2\pi$ radians every $29.53 \cdot 24$ hours, which gives $0.00443 \frac{\text{rad}}{\text{h}}$. Linear speed depend ...
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### How do you calculate the percentage of light-speed a ship with a certain delta-v can achieve, accounting for relativistic effects?

In the case where the spacecraft can achieve relativistic speeds and no gravity is involved, $\Delta v$ is actually $c$ times the maximal change of rapidity which can be achieved. So the maximal speed ...
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### Accuracy of converting from TLE/Orbital Elements to Cartesian if used for other propagator?

If a two line element represented the exact state of a satellite at the epoch time of the element set, there would be zero penalty in applying the SGP4 algorithm to cartesian coordinates, which are in ...
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### Calculating mass expelled from cold gas thrusters

Puffin's answer is correct; this is just a supplemental that was a bit too involved for a comment. A physical interpretation of specific impulse measured in seconds is "the length of time for ...
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### GMAT: Finite burn targeting, solving for burn duration and quaternion

First off: Chris you may already know some/all of my response due to your background. I will attempt to both answer your GMAT question and provide insight to others who may not be as familiar with ...

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