# Tag Info

## New answers tagged orbital-elements

12

I've got a set of Keplerian orbital elements $e_0$, $a_0$, $i_0$, $\omega_0$, $\Omega_0$, and $\theta_0$, and I'd like to get to a different orbit with orbital elements $e$, $a$, $i$, $\omega$, $\Omega$, and $\theta$. How do I calculate (a) the amount of delta-v I'll need for this maneuver or set of maneuvers, and (b) which maneuver or set of maneuvers I ...

9

What you're looking for is Lambert's problem, which is used both for trajectory design and orbit determination, and to produce porkchop plots. Your hunch that this is not a simple problem is correct. pykep has a solver for Lambert's problem that supports multiple revolutions as well as solvers for various related problems such as low-thrust trajectories.

5

All orbits about the Earth except for polar orbits will see their line of nodes precess due to the Earth's equatorial bulge. The effect is strongest for near-equatorial orbits and for objects in low Earth orbit. In the case of the International Space Station, this nodal precession causes the ISS's right ascension of ascending node to decrease by about 5° per ...

4

I'd always imagined its orientation would be fixed in inertial space, but now I'm inclined to say no? Trust your inclination! If Earth had perfect spherical symmetry then the smaller effects like gravity from the Sun and Moon and some other smaller effect would still perturb the ISS' orbital parameters (in addition to the big one - drag - which will pull it ...

-2

Can we determine the position of an artificial satellite using Kepler's parameters? Short answer: Absolutely not. Long answer: The Earth's gravitational field is not uniform, and the Earth's atmosphere, the Sun, the Moon, and the other planets perturb the orbits of artificial satellites that orbit the Earth. Multiple satellites explicitly take advantage of ...

11

I'm assuming atmosphere isn't a consideration. The azimuth angle (north-east-south-west orientation) doesn't matter at all for this question -- it determines the orientation of the ellipse, but has little effect on its shape, and none on the perigee-apogee question. If the elevation angle is zero -- i.e. you're throwing it with a perfectly horizontal ...

2

Short answer, yes. Long answer: There are 6 keplerian orbital elements (but note that these parameters are not the only way to describe an orbit). Semi-major axis, eccentricity, inclination, argument of periapsis, right ascension, and true anomaly. Here is a surface level explanation of each: Semi-major axis describes the "size" of the orbit. In ...

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