Questions tagged [orbital-mechanics]

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. For the movements of celestial bodies, see [celestial-mechanics].

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What exactly is a solar gravity well manouver and in what cases would it be helpful?

In this answer to the gedankenexperiment question With current state of technology if we wanted how long would it take for newly launched probe to overtake Voyagers? I've seen the term "solar gravity ...
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What exactly is “OMS2 Phase Angle”?

The vertical axis of this plot in this answer to How far apart are ISS launch windows? is labeled OMS2 Phase Angle (deg) and I don't know what that is. It's possible that OMS is related to things ...
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What do the shaded vertical lines in the animation of Gravity assists of space probes, mean?

Example Animations from Wikipedia — https://en.wikipedia.org/wiki/Gravity_assist#/media/File:Animation_of_Voyager_1_trajectory.gif https://en.wikipedia.org/wiki/File:...
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How far apart are ISS launch windows?

Being on an eccentric orbit, I imagine the launch windows are instantaneous (which they are) and different for each launch site whether it be Baikonur, Cape, Tanegashima, or the ESA launch site. How ...
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What does the term “libration point gateway” mean?

In the Circular Restricted Three Body Problem, natural paths exist between periodic orbits or the libration points that have negligible cost. These are commonly known as free transfers between ...
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Second derivative of mean motion as indicator of deorbit

I noticed that the second derivative of mean motion (SDMM) is non-zero for only a small percentage of the NORAD catalog. All those objects I checked have reentered since the TLEs I was using were ...
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Why aren't energy and momentum (of a restricted three-body system) conserved, or are they?

The question Is the Jacobi constant stationary along a periodic orbit? lead me to Wikipedia's Jacobi integral, which begins: In celestial mechanics, Jacobi's integral (also known as the Jacobi ...
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How much lead time would a statite need to flyby an interstellar visitor?

Phys.org;s Dynamic orbital slingshot: A cool idea to catch up with an interstellar visitor references the MIT press release To catch an interstellar visitor, use a solar-powered space slingshot and ...
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Is the Jacobi constant stationary along a periodic orbit?

In the book called "Chaotic Worlds: from Order to Disorder in Gravitational N-Body Dynamical Systems", link here, the author states that if the dynamical system has an integral of motion which is not ...
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To cool down Venus, from where would be the most economical way to bring the shadowing material into orbit around the planet?

Edit: With the help of comments below, I've changed the question somewhat. Credit: NASA, Image processed from Mariner 10 images by R. Nunes http://www.astrosurf.com/nunes It could seem that ...
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What is the physical interpretation of the eigenvalues of the monodromy matrix and how are they associated with the invariant manifolds?

To define the monodromy matrix, assume that the period for one cycle of a halo orbit is denoted as $T$, the initial time as $t_0$, and the state-transition matrix is defined as $\phi$. Then, the ...
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Given initial true anomaly and arc length of space flight, figure out new true anomaly

In a hyperbolic orbit/trajectory, if you know the distance traveled, and the initial true anomaly in the orbit, how do you figure out the new true anomaly? You know the mass, eccentricity, axis values ...
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Would the Poynting–Robertson effect ever be faster than a solar sail from a 1 AU orbit to the Sun?

In this answer to Do you need 0 km/s velocity to crash into the sun? I mention solar sails for retrograde thrust and the Poynting–Robertson as two ways an object could ever-so-slowly spiral into the ...
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Do you need 0 km/s velocity to crash into the sun?

I was reading a popular thread about the delta-v required to escape the solar system compared to the delta-v required to crash into the sun. I get it: the earth itself already has a high speed (29.7km/...
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Calculate flight path angle given semi-major axis, eccentricity and distance from the focal point

How can I, given the semi-major axis (α), the eccentricity (ε), and the distance from the focal point (r), calculate the flight path angle (φ)? (As shown above)
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Why is L2 Langrangian point stable?

I was reading about Langrangian points between Sun and Earth. I understood that $L_1$ Langrangian point was stable as the gravitational pull by Sun on the satellite towards itself was equal to the ...
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Are there some three-body orbits that can't be escaped? Can we know without propagating forever?

update: Searching for "choreographies" I found this Physics SE question which is related but different because it asks only if periodic solutions can be proven to be periodic numerically and my ...
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If the Earth spun clockwise, how would that affect Space Exploration?

If viewed from the North Pole, the Earth spins counter-clockwise. Because of this, many satellites also orbit in the same direction as you can take advantage of the Earth's rotation and essentially ...
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When will DSCOVR appear too close to the Sun for reliable downlinking?

DSCOVR is in a Lissajous orbit about the Sun-Earth L2 point. That the orbit is called Lissajous rather than halo means that it's periods of horizontal libration and vertical libration are not equal. ...
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What speed variation would there be in a realistic LEO orbit at a nominal height of 200 km?

So in a previous question, How much variation in orbit altitude is caused by gravitational variation, in LEO? we established that an LEO orbit of ~200 km would actually change altitude by up to +/-20 ...
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Using Space Stations in fixed orbits instead of Space Ships for the Whole Journey

I'm very new, so I hope this question is within the guidelines of this group. I remember an interview with Sally Ride where she mentioned using a larger habitat/space station that was put into a ...
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Two Body Kepler Propogation: Errors from using float / single precision

I am looking into leveraging GPU's for two body orbit propagation. I am doing basic Kepler propagation, and only dealing with circular and elliptical orbits. I took a first shot at using single ...
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How J3 affect orbit's parameters

I'm trying to calculate the effect of J3 on my orbit's parameter (a, e, I, $\Omega$, ...) I start with the equation of the gravitational potential of the Earth : $$U = \frac{\mu}{r}\left(1 - \sum^\...
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How much variation in orbit altitude is caused by gravitational variation, in LEO?

Imagine a hypothetical spacecraft in LEO, at 200km. Ignore air resistance for a moment. It's actual height will vary, due to both gravitational anomalies and the shape of the Earth. Do we know ...
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Why do rockets launching to the ISS from Florida point at 45 degrees to reach a 51.6 degree inclination?

In the Everyday Astronaut video about roll programs, it was mentioned in passing that in order to launch to a 51.6 degree inclination (to rendezvous with the ISS), the rocket must point at about 45 ...
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Who called the Lagrangian points as “Libration” points and and why was the terminology “Libration” used?

I am curious about the naming and why were the equilibrium solutions of the CR3BP called as Libration points? Who called them that and what is the history behind it?
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How to calculate position and velocity from given orbital elements?

I have some orbit, with a given semi-major axis, inclination, eccentricity, longitude of ascending node, argument of periapsis, and true anomaly. How can I, from this, calculate the position and ...
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Aborting a de-orbit maneuver

I was contemplating on how a de-orbit may be abandoned post completion of the orbit burn, say, from LEO. A situation in which this might be necessary would be detecting a breach in the heat shield ...
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How should I understand these phrases in this paper on orbit transfers?

I am studying this article on orbital mechanics and can't understand the meaning of some terms related to mathematics (perhaps because my native language doesn't have such terms). I created the same ...
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Without the accident, would Apollo 13 still have been the farthest crewed mission from the Earth?

This answer notes that the Apollo 13 crew holds the record for the distance that humans have traveled beyond Earth. Had the mission exactly followed the flight plan, would they still have been the ...
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Analytical expression for the ground track of the International Space Station

For a maths task in school, I am investigating the orbit of the International Space Station around the Earth. I understand that when the 3D movement in space is represented on a 2D surface, the ...
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What is the sign of Earth's J2?

From Wikipedia's Geopotential model; The deviations of Earth's gravitational field from that of a homogeneous sphere and the question For the mathematical relationship between J2 (km^5/s^2) and ...
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Will crewed vehicles ever follow multi-flyby trajectories?

A while ago, I asked a similar question here, but I think it was confusing, so nobody answered. Two questions: This one is a bit subjective: Do you think that lengthy (+5y) multi-flyby trajectories ...
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Given an arrival date, is there a way to calculate the declination and right ascension of the arrival asymptote into Mars?

I am designing an Earth-Mars transfer. The launch window is 03-Jul-2026 (departure from Earth) & 22-Jun-2028 (Mars arrival). The declination and right ascension for the departure asymptote from ...
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How significant is orbit propagator choice/error when considering a year-long satellite coverage simulation, and which is the most appropriate?

I'm currently considering a project to simulate the (Earth-seeing) coverage of 1 or more satellites over the course of a year. The point would be to compare how different orbits result in different ...
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How can you construct the periodic orbits around libration points L1 and L2 in the circular restricted three-body problem and prove their existence?

Following up on a previous question about the classification of periodic orbits, how can they be constructed, especially the planar Lyapunov family, around libration points $L_1$ and $L_2$? And how ...
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Is a graviational slingshot around Mercury a feasible solution for space probes?

Our spacecraft have rarely visited Mercury, for reasons obvious to those who know orbital mechanics. The Mariner 10 visit to Mercury was revolutionary by using Venus for the novel slingshot maneuver, ...
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How much does it cost to land on a lunar mascon?

This answer to Delta-v for landing on the moon estimates that to go from a circular orbit at 110km to a landing on a spherical Moon would require an absolute minimum of 1736 m/s and the Apollo landers ...
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Orbit stability

This is my first question. I am a space enthusiast but I don't have a formal understanding of celestial mechanics, so I would like to ask how stable against perturbation an orbit is, given the ...
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Orbit stability [duplicate]

this is my first question, I am a space enthusiast but I don't have a formal understanding of celestial mechanics, so I would like to ask how stable against perturbation an orbit is, given the ...
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Need javascript to solve xyz for a kepler

I have a python program that I use to calculate the xyz positions of a point in a kepler orbit. https://github.com/sczesla/PyAstronomy/blob/master/src/pyasl/asl/keplerOrbit.py It takes the following ...
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What is the analytical closed-form solution of the two-body problem to verify its numerical integration results?

The purpose is to study the motion of two celestial bodies analytically. What is the closed-form of the two-body problem if I was to solve it analytically without using a numerical approximation ...
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How can a meteor gain energy in an encounter with the Earth even though these answers say it can't?

The question Did a spacecraft ever use an atmosphere to accelerate away from a planet? was unfortunately given five down votes and answered with: Entering the atmosphere introduces drag, which ...
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Why is the bend angle of a hyperbolic trajectory giving different results?

The bend angle ($\delta$) is the reflex angle between the two asymptotes of a hyperbolic trajectory. From this Stack Exchange answer, the formula to calculate the bend angle is: $$ \delta = 2 \sin^{-...
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Cartesian vectors to keplerian orbital elements of binary system

I am looking to code a a function that converts my 3d position and 3d velocity of a binary system into keplerian orbital elements of the system. I have seen a few other posts on this but they always ...
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Different results for Orbital Period?

I am making a hypothetical solar system with random masses and distances (but still physically and mathematically accurate). I want to calculate the trajectory of a spacecraft, and to do that, I need ...
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How to get lunar L, B, C parameters from the Moon's 3x3 rotation matrix from the Python package Skyfield?

Answers to What are the “Moon L, B, C” angles shown in this solar eclipse simulation? explain that L and B (or "l" and "b") are the "selenographic coordinates of the Moon's apparent center" (latitude ...
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What space simulators are the most accurate at simulating real world physics?

We've all at least heard of KSP, a popular space flight simulator. its not the best but can teach someone the basics at rocket science, delta V, burntime, basic orbital maneuvers, retrograde, prograde,...
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Aldrin cycler mission to Mars in MATLAB [closed]

I am planning to do a mission project on Aldrin Cycler (Earth to Mars) in MATLAB. Can you please suggest me where to start. I tried reading few research paper related to this topic, any other advice?
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Is a polar geosynchronous orbit described by Viviani's curve?

This answer to Is there a name for the great circle where latitude and longitude are equal? says (in part): More generally, a clélie is the name given to any spherical curve where the longitude $\...

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