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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.

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Space Shuttle Moon Mission? [duplicate]

Theoretically speaking, could the shuttle have performed TLI, LOI, and TEI burns given extra OMS fuel? approximately how much fuel and payload bay space/mass would this take up and might there ...
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Are Lagrangian points associated only with the smaller body?

Diagrams of Lagrangian points I've seen always show the points near the smaller object, following its orbit about the larger one. For instance: from Wikipedia. But in fact the smaller object ...
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What is “propulsive passivation” and why will the SpaceX STP-2 mission do it?

The Teslarati article SpaceX’s Falcon Heavy flies a complex mission for the Air Force in launch video discusses the upcoming third Falcon Heavy mission STP-2 and quotes the caption on the linked ...
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How accurate can a point in space be determined by the likes of the ICRF?

How accurately could a 3D point in open space (i.e. not on an object), say at an elevation of 30,000m above sea level, be located or modelled using the likes of the International Celestial Reference ...
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How can I calculate the azimuth from an earth station to a satellite

I have computed the ecef coordinates of both the user location on the ground, the satellite's ecef coordinates, as well as other inputs such as altitude, lat, long of both satellite and earth station....
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How to use “patch points” to make a continuous halo orbit?

update: I've found "patch points" mentioned throughout the following papers; it is likely that an answer can be found from these sources. Targeting Cislunar Near Rectilinear Halo Orbits for Human ...
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Converting Keplerian coordinates into Latitude and Longitude

Introduction My goal is follow up the title of this question and obtain the Earth coordinates (latitude, longitude) from the keplerian coords ...
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Transfer between circular orbits in up to 5 maneuvers

There are 2 circular orbits with different inclination and RAAN. I have to transfer from a specific point (true anomaly given) of one orbit to a given point of another in 1 month. The period of the ...
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How to implement SGP4 C++, satellite propagator?

I would like to ask about how to implement the SGP4 code in C++ by Vallado. How can I implement the libraries that are available in https://celestrak.com/software/vallado-sw.php. I think that are the ...
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Can someone help Scott Manley explain this Snoopy-capturing maneuver?

In his recent video Apollo 10's Lunar Module Snoopy Is Lost In Space - Could We Bring it Home? Scott Manley uses some fancy supplemental techniques in KSP to simulate and explain a possible mission to ...
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Explanation of single-burn trajectories from Lunar surface to Earth surface

I learned of the fine book Soviet Robots in the Solar System from this excellent answer. One chapter in it describes how the Soviets had extreme mass limitations on their lunar sample return vehicle ...
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Would a standard gravity turn still be the most optimal path to orbit if Earth did not have an atmosphere?

If Earth had no atmosphere, then would a standard gravity turn still be the most optimal path to orbit? Why or why not?
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Is the Gateway's halo orbit bound to Earth? Would the Gateway remain in Earth orbit of the Moon disappeared?

Discussion below this answer involves my feeling that calling halo orbits in very asymmetric systems (e.g. Sun-Earth or Earth-Moon) as orbits around the primary, in 1:1 resonance with the secondary. ...
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Can someone give me a 'trajectory optimisation for dummies' answer?

So, I am currently doing a project on trajectory optimisation. I get the principle of it, minimise fuel cost for a journey, or try to maximise the spacecraft weight at target destination, and that ...
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Reference to understand the notation of orbital charts

To address various orbital evolutions of spacecrafts, some particular orbital charts are taken into account. For example, the following is used to depict how a chaser reaches a target: The only thing ...
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How would off-apsis burn effect the angle and position of new apoapsis

Let's say you have an elliptical orbit, if you burn prograde at the periapsis, you extend the apoapsis by some factor(according to vis-viva equation). But if you burn prograde on somewhere during the ...
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What orbital mechanics toolkits available today are suitable for a real-time simulator?

I'm a software engineer and I've always loved Orbiter (also here). However I feel that it's growing a bit antiquated, and it would be nice to have a more modern, open source, or otherwise hackable ...
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What Methods are Used for Satellite to Site Visibility Calculation?

In the paper, Rapid Satellite-to-Site Visibility Determination Based on Self-Adaptive Interpolation Technique it is claimed that "Satellite-to-site visibility periods are typically determined by the ...
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On the dynamics of two connected objects located at different circular orbits

I'm just thinking about the qualitative and quantitative implications of a hypothetical orbital problem, but what I ended up does not make sense as it should. In particular, assume that two objects ...
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Where did the Herschel Space Telescope go in 2013?

The Herschel space telescope wins as largest optical telescope mirror in space when "optical" includes far infrared (~55 µm). The Wikipedia article Herschel Space Observatory lists the orbit as ...
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What are the orbital-mechanical advantages of a long (100+ second) sub-orbital coast phase?

This answer to Trajectory to get into orbit says: In most real launches to low Earth orbit, the burn continues from liftoff until orbital insertion, without a coasting phase. Some (like Antares) do ...
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Which two spacecraft have spent the longest times in libration point orbits? (halo, Lissajous, etc.)

Libration point orbit is a general term including halos, Lissajous', and a whole zoo of others associated with Lagrange points in three-body systems. Which two spacecraft has been in such an orbit ...
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Can we calculate elliptical properties in a spherical coordinate system?

Can we calculate the elliptical properties like the semi-major axis and eccentricity using the state vectors (position and velocity) in the spherical coordinate system? http://www.braeunig.us/space/...
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Did DSCOVR travel “along the stable manifold of it's future SE L1 Halo orbit” to get there?

I just wrote (and have since removed) the following paragraph in this answer: As can be heard in this video SpaceX's launch of the DSCOVR spacecraft to Sun-Earth L1 went there almost directly. The ...
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Apollo 15 State Vector recreation

I am trying to get the state vectors for Apollo 15 before, during, and after critical manoevers [sp]. IE TLI, LOI1, LOI2, lunar launch, preocking, postdocking, and TEI. I am a totally newbie at all ...
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Design of return trajectory from lunar polar orbit to Earth's atmosphere

Given a flight path angle, altitude and velocity at re-entry into the Earth's atmosphere, how do I go about designing the return trajectory from a polar orbit at 17km altitude about the lunar surface ...
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Using Differential Equations to model path of satelite around earth

I am new to GMAT and am hoping to use it to model the path of a Low Earth Orbit satellite around Earth. I am thinking of plotting the path on a plane and using polar coordinates to model the path ...
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What is the formula for Legendre Polynomials from EGM96 calculated in F447.f program?

The F447.f program is designed to calculate the geoid undulation for EGM96. I'm trying to understand how it accomplish this calculation. I stuck in ...
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How much Delta-V is needed for Orbital Maintenance?

My question is aimed at understanding the how much Delta-V is needed for orbital maintenance for different orbits. Obviously, there still is some residual air resistance that decreases as the orbital ...
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How do I calculate re-entry velocity when decaying from a circular orbit?

I am trying to find the velocity of an object during re-entry so that I can calculate the peak heat flux but I'm a bit stuck. I know how to find the velocity of the original, circular orbit (300km) ...
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Sun synchronous orbit and LTAN

I have to size the electric power system for a satellite on a circular, sun-synchronous orbit at 800 km altitude. In the problem I have been given the LTAN (Local Time of the Ascending Node) also, ...
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How do I calculate the change in the argument of periapsis after a plane change maneuver?

Let's say I have a spacecraft in an initial geocentric orbit with the following parameters: a = 7,960,000 m, e = 0.010, $\Omega$ = 180$^{\circ}$, i = 98$^{\circ}$, $\omega$ = 90$^{\circ}$, $\theta_0$ =...
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Is it possible to have an orbit around the earth and the moon

I was just wondering if it were possible to A) Orbit the moon and earth B) To orbit any two celestial bodies really?
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Why are JPL using this expression to emulate Schwarzschild orbits?

From the documentation ”Formulation for Observed and Computed Values of Deep Space Network Data Types for Navigation ” expression 4-61 on page 4-42 it can be seen that JPL uses the following ...
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How spherical is the Hill Sphere?

...because I have a budding sense it's not quite spherical. Or at least the center isn't equal to the body's center. For one thing, at the distant end (say, in case of Moon's Hill Sphere, the point ...
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Would a self-winding watch work in space without gravity?

Could a watch that winds itself with a pendulum work in space with no gravity? Could a pendulum or the self winding part be modified to work off the movements of the wrist in a microgravity ...
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Using the distance components to calculate minimal dV randezvouz trajectory

The are objects on 100 circular orbits, 1 object on each orbit. One orbit is said to be initial (I) and others are final (F) . ...
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Getting from LEO to a station in geostationary orbit and docking with it using a Hohmann transfer?

How long would it take for a spacecraft with a mass of 30,000 kg, to go from LEO to reach and match the speed of a space station in geostationary orbit so it could dock with the station, using a ...
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A software for orbit propagation, considering Moon, Sun and zonal harmonics

I have to propagate the orbit of a satellite in 1 year, complying with the Sun, Moon and zonal harmonics effects. Is there preferably a free software, which could be used? I was suggested to use ...
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How does the poliastro python package “Going to Mars with Python” example work? What's it really doing?

@astrojuanlu's answer mentions the existence of the Python package poliastro, and in the documentation there I found an example titled Going to Mars with Python using poliastro among others. Input ...
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Lambert problem solver needed for custom gravity in Python

I need to solve the Lambert problem, however, I have a custom gravity model. My ODE of motion is: ...
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What is the maximum mass of a satellite that can be placed in GEO?

What is the maximum mass of a satellite that can be placed in GEO? Or can satellites of any mass be placed in GEO?
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Formula in “Hidden Figures” Movie

In the scene where Katherine Johnson/Taraji Henson has to calculate "Go / No-Go," which I take to mean the operational go-no-go orbital-insertion criteria. She calculates a value for R, using this ...
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Delta V to get to the Sun-Earth Lagrange Point 1?

For any of these starting positions, GEO, GTO, EM-L2 or EM-L4/5, which would require the least delta-V to get to Sun-Earth L1? How much delta-V would it require? Would this chart help in identifying ...
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How to calculate the planets and moons beyond Newtons's gravitational force?

The question Calculating the planets and moons based on Newtons's gravitational force was pretty much answered with two items: Use a reasonable ODE solver; at least RK4 (the classic Runge-Kutta ...
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Is there a general relativistic relativistic rocket equation?

I am not to familiar with rocket equations but I know that if you combine special relativity with classical mechanics you get "c" as a speed limit. Basically the closer you get to "c" the more you ...
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How to find instantaneous positions of a central body of specified mass that results in an osculating orbit?

If I understand correctly, osculating orbital elements such as those posted in JPL's Horizons represent the mathematical osculating (tangential or "kissing") Keplerian orbit about a specified location ...
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Will NASA put astronauts into a polar lunar obit? If so, how?

The NASA news item New Space Policy Directive Calls for Human Expansion Across Solar System says: New Space Policy Directive Calls for Human Expansion Across Solar System and the administration is ...
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Calculating orbital parameters for given requirements

I'm trying to determine what's the best way to calculate the required orbit for a LEO remote sensing satellite. I understand there exists the trade-off between sensor coverage and sensor accuracy, but ...