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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3answers
7k views

Is Earth's Surface “In orbit”?

I'm having trouble understanding relative angular/tangential speeds at increasing altitudes above Earth's surface. In particular, I find this comparison of tangential velocities on Wikipedia very ...
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What exactly is the relationship between the orbits of Neptune's moons Naiad and Thalassa?

Scitechdaily's Wild Orbits of Neptune Moons a ‘Dance of Avoidance’ [Video] links to the YouTube video Neptune Moon Dance (Naiad and Thalassa) and says: In this perpetual choreography, Naiad swirls ...
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1answer
328 views

Are the orbits of all triple star systems at least technically unstable?

Background: In the Circular Restricted Three Body Problem (CR3BP, CRTBP) some halo orbits are mathematically stable. That means that the orbit of the third body is closed, periodic, and stable ...
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1answer
57 views

How to find the Orbital Period of two Binary Planets around a Single Star?

This is kind of a weird one. Bare with me! :) Background: (Skip to the math below if you just want to answer questions) In my favorite game, Elite: Dangerous, I "own", or occupy I guess, a system ...
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1answer
110 views

Given that Kepler's Third Law as stated on most websites doesn't include mass, how does it work for planets in other star systems? [duplicate]

Kepler's Third Law as stated on websites I found while searching for "how to convert between a planet's orbital period and semi major axis" is $P^2 = A^3$ where P is the orbital period in years and A ...
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1answer
76 views

Orbital speed is (vector) sum of tangential and normal speed?

Orbital speed definition in wiki does not state clearly - it is just tangential speed component or square root of squares of normal and tangential speed (full speed vector). When we say that moon ...
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1answer
68 views

Could someone please explain to me how I can extract velocity component values from Stellarium, for a given planet?

For a project that I am currently working on, I would like to know how one could extract velocity component values ($v_x$, $v_y$ and $v_z$) for a planet from the Stellarium software. The current ...
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IAO 2015 Question 1 Noon at the Olympiad

Yesterday, on October 16, 2015, the upper culmination of the Sun at the venue of the Olympiad was at 11:29:44 local time. Calculate as accurate as possible at what time the upper culmination of the ...
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4answers
8k views

Would an object shot from earth fall into the sun?

Would an object shot from earth fall into the sun? If an object is shot at 107,000 km/h via rocket or otherwise, in the opposite direction to our orbit about the sun, it will be traveling at 0 km/h ...
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1answer
96 views

Propagate Earth trajectory for 1 Myr

What is the most accurate way of propagation of Earth trajectory relatively to the Sun? I need to calculate the Earth-Sun distance. Is there any library on Python? I've used before JPL Horizons, ...
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1answer
108 views

Would two Earth-like planets on opposite sides of a Sol-like star at about 1 AU be a stable configuration?

Would two Earth-like planets on opposite sides of a Sol-like star at about 1 AU be a relatively stable configuration? I understand that there are tadpole-like orbits and the two planets may not stay ...
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2answers
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Change of orbit with change of mass?

In the science fiction book 2010, monoliths increase the mass of Jupiter until it becomes a star. https://en.wikipedia.org/wiki/2010:_Odyssey_Two The Leonov crew flees Jupiter as a mysterious dark ...
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1answer
63 views

Origins and most frequently used; perinigricon vs peribothron?

Gizmodo.com's Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole mentions Sgr A*'s companion gas cloud G2 and that Wikipedia article uses the term perinigricon, but that mentions ...
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80 views

How does the orbit of a 2-body system evolve as it orbits a more massive 3rd body?

I have been reading up on how multiplicity of star systems decline with star mass, which implies a relatively common occurrence of binary star systems orbiting more massive stars. I would imagine this ...
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41 views

Speed of Moonrise relative to fixed point on ground

Due to the curvature of the earth, and the way the moon interacts with the atmosphere (especially close to the horizon), is there a known function that describes the speed of the moon relative to its ...
4
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1answer
118 views

How do a planet's moons and a planet's rings interact?

I am making a video game which features a planet and its moon. And I thought I would add rings too. But that got me wondering... how do a planet's moon and a planet's ring influence each other? Does ...
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1answer
62 views

periodic inclination change circumbinary planet

I am studying circumbinary planets and I made a python model to calculate certain properties of the orbits, and when I calculate the inclination I get a sine wave. I do not see a way to predict the ...
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1answer
154 views

Can Eight Retrograde (seen from Earth) planets occur?

First of all, for the purposes of this question Pluto is a planet. So the eight planets being considered are Mercury, Venus, Mars, Jupter, Saturn, Uranus, Neptune and Pluto. My question is: can all ...
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1answer
57 views

What kind of effects can maintain Uranus' rings' eccentricities?

The recent paper Thermal Emission from the Uranian Ring System has been in the news recently. The introduction mentions: The ε ring, the brightest and most massive of the narrow rings, was shown to ...
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1answer
67 views

How can the oblateness of Earth impart torque to change the longitude of ascending node of a satellite?

I've read that you can change the longitude of ascending node of a satellite (i.e. changing the orbital plane without changing the inclination) to change its orbital plane by using the torque imparted ...
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0answers
34 views

Calculation of day lengths of moons or moons of moons

Is it possible to calculate the day lengths of moons or moons of moons? If so, does the day length depend on the longitude as well as the latitude? Also, if we calculate the day length, is it possible ...
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1answer
605 views

Why isn't Earth tidally locked to the sun?

Given that the moon has long been tidally locked with the Earth, why isn't Earth (or any of our other solar system's planets) tidally locked to the sun?
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How to choose between methods to resample/interpolate ephemeris state vectors? Are there recognized techniques for orbital data?

I have ephemeris data for state vectors of a satellite in a J2000.0 coordinate system. This data is already filtered and cleaned. The data sample rate ranges between 1 second and 60 seconds, and I ...
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2answers
115 views

How was this interstellar fireball observed and its trajectory analyzed?

The short, interesting paper Discovery of a Meteor of Interstellar Origin describes a proposed discovery of a second interstellar object. This one hit the Earth, and was discovered not by telescope, ...
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2answers
113 views

How to determine the eccentricity, knowing the orbital speed and distance

How to determine the orbital eccentricity of a planet, knowing the instantaneous orbital speed of it and the distance from the Sun to the planet at that moment?
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1answer
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What is the force that changes a satellite’s inclination when orbiting a planet with an equatorial bulge

I tried looking this up without success and I imagine there's a formula for it, with some ridiculous numbers like it drops off to the 5th power of the distance or maybe even more. Imagine a planet ...
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How to draw an orbit from Orbital Elements using Transform3DGroup

I am trying to draw an orbit using the Transform3DGroup class in the C# .NET framework. I have orbital elements a, e, i, RAAN, ArgPer, trueAnom. The algorithm that spits these out for me also gives me ...
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3answers
134 views

What orbit is the smallest or takes the least time to complete?

What orbit in our solar system would take the least time to perform 1 orbit? What is the fastest possible orbit to complete in the universe?
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2answers
117 views

What natural mechanisms could lead to the unlikely case of the same rogue asteroid or planet passing through our solar system twice?

I find he following answer to the question What's the soonest Oumuamua could return? unsatisfying and oversimplifying and the last five words "Therefore it will never return." unsupported at a minimum....
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0answers
35 views

Does a planet's rotation speed and distance from its star influence the precession of its axis? And is the Earth's precession “normal”?

I guess first off, do all/most planets with a tilted axis experience precession? And if so, is it usually in the same direction (clockwise or anticlockwise)? What I'm really curious about is if a ...
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Energy conservation in Interplanetary orbit transfer [duplicate]

When a spacecraft flys past a planet eg. Jupiter , its heliocentric energy increases dramatically allowing it to go further away. How is this possible without using any more rocket fuel?
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2answers
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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
71 views

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
68 views

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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0answers
31 views

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
67 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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2answers
152 views

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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2answers
96 views

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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1answer
84 views

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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1answer
51 views

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
191 views

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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0answers
53 views

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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0answers
50 views

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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2answers
170 views

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
71 views

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
82 views

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
93 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
141 views

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
291 views

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
105 views

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 ...