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Questions tagged [orbital-mechanics]

The application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft.

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How to calculate the argument of perihelion for exoplanets with incomplete orbital elements?

I'm trying to simulate the Kepler-444 exoplanetary system using data from this website. The problem is that there is no argument of periapsis parameter for the Kepler-444 system, so while I think I'm ...
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1answer
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How was Cruithne's orbital time calculated?

How was it determined that Cruithne takes 770 years to complete its cycle with Earth? Janus and Epimetheus were disovered long enough ago, and have short enough cycle times, that we've had time to ...
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1answer
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Rendering asteroid orientation as seen from Earth

I am writing a program to render an asteroid as seen from various parts of the solar system. My goal is to roughly reproduce the image of Cacus according to information on its DAMIT detail page. ...
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Tides with 3 Largish Moons [closed]

As part of my worldbuilding for a book, I’d like to have a planet with extreme variance in its tides. I want lowest tide reveal about 30 miles of floodplain, and occasional massive tidal waves. I ...
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1answer
64 views

How close would the orbit of Mars have to be to that of the Earth to induce a collision?

When the Earth passes by Mars they exert a slight gravitational pull on each other, but the force is so small that their orbits are not significantly disturbed. However, if we imagined that the ...
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What variables are needed to calculate simple horseshoe orbit times?

EDIT This was NOT a duplicate of Horseshoe orbit cycle times. But that other question has been deleted, regardless. My original question asked for the answer to the equation(s), and provides many of ...
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How do we know that an exoplanet is tidally locked to the parent star?

Often in discussing exoplanets we hear that they are close to the parent star (usually a red dwarf) but then there's a caveat that the planet is tidally locked to that star and that that fact severely ...
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does the orientation of orbital plane of our solar system rotate with the galaxy

As I understand it, our solar system travels through the milky way with the orbital plane tilted about 60 degrees so that we are sort of traveling in the direction of earth's north. My question is if ...
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Computing the local orbital frame vector directions in a geocentric reference frame

In the context of the study of a cubesat (little satellite), I am asked to define the local orbital frame and compute the local orbital frame vector directions as a function of time : Here the ...
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2answers
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Calculation of Eccentricity of orbit from velocity and radius

For a school project I am making a gravitational computer model. As I want to Milankovitch cycles, I need to calculate the eccentricity of an orbit after the model has completed its simulation. I ...
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How to convert a function of keplerian elements to a function of equinoctial elements?

I need to convert the Keplerian orbital elements to the equinoctial elements and then use the converted elements"equinoctial" in the function "d" below. To do this, first, I converted the Keplerian ...
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Expansion of Jupiter's perturbing effects on Kepler's third law treatment of orbits?

Does anyone know any good reference for how this was done? I remember reading once about how Jupiter's gravitation can be treated as a perturbation, but I cannot find it again now. I think they ...
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How long is a “lunar month” in Jupiter?

For Earth, the lunar month is well known. But Earth has only one moon. But on Jupiter, how long does it takes for the same moon configuration to appear in the "sky" of the planet? For the sake of ...
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1answer
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Extract anomalies from two-line element set (TLE) on ISS (International Space Station)

I am faced to a problem of interpretation illustrated on figure below : From wikipedia : Two-line element definition, I can extract the following meaning anomaly : 308.7017 ° (in degrees) But in ...
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1answer
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What is the range of the zenith angle between velocity and position vectors?

I'm coding on a space simulator and I want to draw a predictable orbit for a satellite. I have read about orbits on http://www.braeunig.us/space/ and under the section "Launch of a Space Vehicle" they ...
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1answer
84 views

Can a moon have a moon? [duplicate]

Is it possible for a natural moon to have a natural moon? What is the limit to when satellites on satellites becomes to unnatural for it to be possible?
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2answers
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Is there a name for this type of orbit of a natural satellite?

Is there a name for the orbit of a natural satellite of a planet who's period is the same as the rotational period of the planet, but the orbital motion has the opposite sense than the planet's ...
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1answer
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Why is Neptune true anomaly decreasing?

So I've been having fun with trying to determine where the perihelia of different planets are (using JPL Horizons). And by the time I got to Saturn, something weird started happening. I've noticed ...
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1answer
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Can a liquid be used to de orbit debris?

Can a liquid be used to slow a satellite to loose orbit by adding or taking momentum from a satellite, a type of devise that releases a liquid that expands and solidified adding surface area making ...
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3answers
650 views

Calculate Earth's distance travelled in a year

This is probably more of a math question than astronomy, but I'd like to know the distance the Earth travels in one revolution around the sun (i.e. a year). According to the data in Wikipedia, I ...
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1answer
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How far from the Sun can an Earth TCO (temporarily captured orbiter) go after leaving?

Objects which are temporarily captured into an Earth-Moon system orbit (temporarily captured orbiters or TCOs) by definition will leave this orbit. While the term suggest an Earth orbit, it's really ...
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Problems with computing X,Y,Z positions of planets at a certain time in Unity3D (C#)

I'm trying to create a little program in Unity3D that positions the planets in 3D space at a given time. I've followed this document: http://stjarnhimlen.se/comp/ppcomp.html. Using the data from ...
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1answer
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Is the orbit of Sirius B based on observation, or derived from the variation in proper motion of Sirius A?

It is common to base models on deduction rather than empirical observation. The orbit of Sirius A is easily seen as variation in proper motion. The orbit of Sirius B, has it been observed, or is it ...
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1answer
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What exactly are the “ν6 secular Sun-Jupiter-Saturn” and the “1:4 Sun-Jupiter” resonances?

In the recent Acta Astronautica article The edge of space: Revisiting the Karman Line, Harvard-Smithsonian Center for Astrophysics astronomer, Space SE contributor and "inverse namesake" of asteroid (...
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What are Kepler's laws (as he wrote them)?

There are of course many, many sources that quote Kepler's laws of planetary motion. This is preventing me from finding out what I really want to know: which is - what are Kepler's laws as he wrote ...
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2answers
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Do all orbiting objects have barycenters?

From the simple perspective of someone like myself, it appears that our sun is "fixed in place" (from the perspective of the solar system itself) and that everything else of lower mass orbits around ...
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1answer
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Calculating obital velocity from radial velocity

I'm not really a physicist so I don't know if it's possible to get the real orbital velocity of a star from its radial velocity. I'm working on a paper for school and I want to get the mean velocity ...
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2answers
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Can Two Stars of One Same Type Orbit Each Other?

This is a simple, textbook definition of a binary star orbit. One low-mass star orbits a higher-mass star in a narrow but definitive center. For example, the high-mass star would be our own sun--a G-...
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1answer
39 views

Calculate eccentricity from apside altitudes? [closed]

I need to calculate the eccentricity of a satellite orbit with only the apside altitudes (height above the surface of the Earth), 400 and 1500 km. However, I don't know the semi-major axis ($a$) or ...
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1:1 resonance of two planets around a star in close proximity - approximate perturbative mathematical treatments?

This question is primarily about the mathematics of orbital mechanics. The circular restricted 3 body problem (in 3 dimensions) assumes two massive bodies in circular orbits around their center of ...
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2answers
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horseshoe orbits

I'm designing a moon system for a fictional setting, and recently came across the idea of horseshoe orbits. The gist of my question is how many objects can share a horseshoe orbital at a time? I ...
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1answer
753 views

Why does the Earth's orbital eccentricity oscillate with a period of about 100,000 years?

This answer says: Earth's orbital eccentricity varies over time from being nearly circular (low eccentricity of 0.0034) and mildly elliptical (high eccentricity of 0.058). It takes roughly 100,000 ...
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2answers
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How can Earth-Sun Lagrange points L1 & L2 even be semi stable considering the moon?

I know that the Earth-Sun Lagrange L1, L2, and L3 points are not considered stable over longer periods, especially when compared to L4 and L5... But, with the moon orbiting the Earth in the general ...
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2answers
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Can a solar system exist where the second planet rotates fast, and the third planet is tidally locked to their star?

Today I read about the Romulan home star system and it looks like it might be impossible for such a star system to exist. Memory Alpha describes Remus: Remus was tidally locked, with one ...
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Do other planets affect the Earth?

Let say Mercury, Venus, the Moon were all in alignment between the Earth and Sun. They are all closest to each other in respective elliptical orbit. On the other side of the Sun you have the rest of ...
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1answer
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How much are Neptune's and Uranus' orbits perturbed by Pluto and other KBOs?

Reading another question, I came across the argument that inconsistencies in Neptune's and Uranus' orbits lead to the discovery of Pluto. This brief write-up mentions Percival Lowell and William H. ...
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1answer
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How can tidal heating lower Io's orbit?

This answer to the question Is Io a magic energy machine? suggests that the energy from the internal heating of Io due to tidal "squishing" as it moves cyclically closer and farther from Jupiter in ...
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Is Io a magic energy machine?

Io gets its volcanic heat from being flexed by Jupiter's gravity, and this seems to go on forever. That sounds like a magic energy source, since Jovian gravity is perpetual and Io seems to remain in ...
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2answers
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Does anybody know how to get Sun-Jupiter Lagrangian points L4 and L5 RA and Dec?

I wanted to point at the L4 and L5 of Sun-Jupiter to find Trojan asteroids but I don't know how to calculate the RA and Dec of these. Do you know of any software that does it for you or how to ...
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1answer
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Maximum distance for earth eclipse

First of all sorry if this question was already asked, but I made a small search here and on google and I couldn't find any answer, so.. Here I am. I was reading NASA's webpage about the Webb ...
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Aaditya L1 mission ISRO

ISRO's next mission to the Sun is Aditya-L1, (also here), which will be placed at the Sun-Earth Lagrangian point L-1. Why it is not placed near L-4 or L-5, since these are stable equilibrium point ...
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1answer
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snapshot of solar system

I am working on a little project where I want to simulate the solar system to teach myself working with python and OOP. I want to calculate the orbits "real", from tangential velocities and ...
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1answer
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Orbit of Mercury

As observed from the earth, the sun appears to move in an approximate circular orbit. For the motion of another planet like mercury as observed from the earth, would this be true? If not, why? What ...
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2answers
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Eventual outcome of tidal acceleration and deceleration

So, I know the Moon experiences tidal acceleration from the Earth. And, from what I've read, if not for the fact that the sun would boil away the oceans and engulf both of them first, about 50 billion ...
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4answers
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Can one approximate the semi-major axis of an orbit as the average orbital distance for eccentric orbits?

Kepler's 3rd Law (regarding the relation between orbital period and the semi-major axis of an orbit) applies to all elliptical orbits. But as I understand it, the only reason it is safe to use the ...
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1answer
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How do comets and other solar system bodies gain energy to exit the solar system?

I recently learnt that some comets like C/1980 E1 (Bowell) interacted with objects like gas giants in the solar system and gained enough energy to exit the solar system. But from Physics, I know that ...
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1answer
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How much could Earth's orbit shift without causing an ecological catastrophe?

Seeing the news about A/2017 U1 made me wonder what would happen if a similar object, but with a mass close to Earth's, had a close call with Earth. Could it shift Earth's orbit enough to quickly and ...
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When the Moon formed and early on, did it orbit over the Earth's equator?

Or was it always at about 5.14 degrees inclination or has the inclination changed over time? See diagram. James K's answer to this question got me thinking about this, and I don't mean to call him ...
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If the moon's orbit decays- how would it effect the moon's phases? [closed]

If a planet passed near the moon and caused its orbit to decay down to earth- how long could it take and how would that effect the visible phases of the moon on earth?
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1answer
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Moments of inertia of planets

The three principal moments of inertia of Earth and Moon are reported, for example, in T. J. Ahrens, Global Earth Physics - A handbook of Physical Constants. I have found reports of the moment of ...