# 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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### Commercial 3DoF/6DoF trajectory simulation and optimization tool for launch vehicle

Is there any 3DoF/6DoF trajectory simulation and optimization tool for launch vehicles like POST available commercially? If there whether it's how reliable when it comes to using for real-time ...
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### Earth Rotational Vector and Orbital Inclination

I'm doing a project regarding orbital launches and i'm kinda confused about how to calculate orbital inclination from launch sites. I've simplified my model so I can ignore fuel and the rocket ...
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### Free Return Transfer Problem

I'm trying to understand how a free-transfer return works. It makes sense to me conceptually, but putting numbers to it it is unclear. I'm not sure how to obtain information about the transfer ...
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### Velocity Vector Transformation for Point Ahead Angle and Doppler Shift Calculation for Inter-Satellite Link

So, I have the Radial and Tangential Velocity Vector (like in Figure 1) and also the Cartesian coordinate of 3D velocity vector. For reference, you can see in this link. Where, $o_{dot}$ vector matrix ...
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### Were there any identified launch windows and gravity-assist trajectories that could put a probe on a “Grand Tour” trajectory around 1981?

For context, I am developing an alternate history that features a far more ambitious Voyager program than the one undertaken in real life. However, despite the increase in NASA funding provided in the ...
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### How to plot conic from Lambert solver

I am trying to solve for an optimal multi-gravity assist trajectory from Earth to Saturn using Matlab. I have already solved for the departure and arrival velocities from and to each planet using a ...
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### Tools for testing look angle generator?

I'm looking for a software test tool with a specific capability: Given the lat/long/altitude of a point on the ground and the az/el/range from that spot to a point in space, generate a TLE for a ...
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### Converting data from NASA's Trajectory Browser into state vectors

I've found this super awesome tool, provided by NASA, called Trajectory Browser. I would like to simulate some of the trajectories listed there but can't quite figure out how to convert the trajectory ...
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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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### Would a Hohmann transfer within LEO be useful?

Hohmann transfer is often used between a lower LEO orbit and MEO, GTO, GEO or beyond. But if the target is a high altitude within LEO, how would a direct ascent compare to ascent to a lower orbit ...
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### Speed needed for the ship to escape Mars, on The Martian movie

Based on the two speeds and altitudes that are presented in the movie: "The Martian" which are respectively 741 m / s and 1350m, 850 m / s and 1843 m I would like to prove with calculations whether or ...
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### Cis-L2 Libration Point Halo Orbit

Queqiao became the first satellite to orbit the Cis-L2 libration point (far side of the moon). Link: https://en.wikipedia.org/wiki/Chang%27e_4 Does anyone have any insight on how to model this orbit ...
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### What do terms of NASA's event list of SOHO mission mean?

In the SOHO mission Event List SOHO Event List there are a few terms I am hoping to understand. I assume MCC1 X-1 Burn refers to a mid-course correction. What does the number 1 and X-1 mean? For ...
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### What was the speed (avg, min, or max) of ARTEMIS-P1 spacecraft as it orbited L1 and L2

If not specifically ARTEMIS-P1, then what is the average speed (or mins and maxs) of a spacecraft orbiting EM L1 and L2 in halo and Lissajous orbits? Are there varied orbital periods for those points?...
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### How to make satellite ground track on map?

I want to make satellite ground track using matlab. I already had a position of satellite(ECI) by solving Kepler equation. And I know convert ECI to ECEF using rotation determinant. Then I convert ...
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### How to get from the perturbative acceleration formula to the acceleration on the 3 axis in the case of the oblate Earth, considering j2?

If we start from the pertrubative acceleration formula, how do we get the expression for the acceleration for the 3 axis written under that form. I've used the partial derivative for the gradient ...
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### Calculating t(E)

The mean radius vector of an elliptic orbit is equivalent to the semi-major axis. If I sample the radius vector of an unperturbed elliptic orbit as a function of the eccentric anomaly with at a ...
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### What is optimum data interval algorithm for Orbit Determination?

I am trying to find Optimum data interval algorithm for orbit determination. Because in Leo, Geo orbit updates the measurement data can be different so that I want to implement an optimum data ...
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### MATLAB optimization script for Low - Thrust trajectory

I'm trying to write a script for a 'shape based' trajectory, based on the exponential sinusoid shape, for an Earth - Mars transfer. Essentially, I know where I want to start, and I know where I want ...
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### Azimuth and elevation meaning relative to satellite (not earth)

I'm trying to find out the meaning of azimuth and elevation form the perspective of a geosynchronous satellite. So if I'm trying to direct a radio beam toward earth from a communication satellite and ...
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### Orbital motion of Lissajous orbit?

Lissajous Orbit Demonstration In the demonstration, I do not get how is it possible for any object to orbit around the L2 point if there is no massive celestial object at the L2 point?
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### Elevation and Azimuth of satellite in different location

I know the Elevation and Azimuth of the a specific GPS satellite (I have the RINEX files of the station in a specific Location 4.4801,-73.3433; in order to calculate this), but I want to know the ...
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### Calculate True Anomaly in future

I am working on a little orbit simulation game. I already got it working previously. But I am changing my system up a bit on how I calculate it. Previously I calculated the true anomaly with time and ...
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### Can someone show me the math behind an Oberth maneuver around the sun, and acceleration to Jupiter?

I'm writing about a spaceship that drops past L-5 from Mars to the sun, performs a tight Oberth maneuver (@ 10 million K from sun?), has 1.5g acceleration at perihelion, but loses thrust before ...
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### Mascon gravity causes tidal lock

Do lunar mass concentrations (mascons) create the gravitational force which causes the near side of Moon to be "tidally locked" so that it always faces toward Earth? see https://www.sciencedaily.com/...
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### Translate/shift ECEF coordinates given certain distance

I have some orbits in ECEF coordinates overlapped at the origin, and I would like to "move" some of them given a certain distance from the original orbit similar to the following picture: ...
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### How fast could a stone be thrown using a sling while standing on the moon?

Similar to this question except not about using a machine: What payloads and launch speeds could a sling launcher get using modern materials on the Moon? How fast could a stone be thrown using a sling ...
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### Covariance Matrix for Space Surveillance Sensors

I have been trying to study the uncertainties associated with the orbital elements for LEO satellites determined by various Space Surveillance sensors around the globe. However, I am unable to find ...
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### Reasonable argument of periapsis?

My intuition for orbital parameters is still poor, so I'm wondering if someone can tell if my argument of periapsis seems reasonable. I'm simulating a launch from Kennedy (28.1 deg latitude, -80.6 deg ...
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### Orbit design guidelines for rendezvous with ISS?

Are there guidelines for orbit design if you're launching a payload for delivery to the ISS? Altitude, maybe phase angle constraints? Orbital approach maneuvers, maybe? I've figured out how to control ...
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### Using the Clohessy-Wiltshire equation, what would be the expression for ' r '?

I'm looking for an expression for r. The difficulty I'm facing is simplifying the C-W equation
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### Is a 2:1 “figure-eight” Lissajous orbit possible in the Circular Restricted Three Body Problem?

Was Queqiao in a halo or Lissajous orbit? Why do sources disagree? says Proper halo orbits have the same period for their in-plane oscillations and out of plane oscillations, so they are closed ...
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### Roughly express how much of our Moon's apparent libration amplitude seen from the Geocenter is due to different effects?

My understanding is that when tidal locking of a body first happens it transitions from a state where the average rotation period is faster than the orbital period to a state where they are the same ...
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### How model 3-stage rocket to LEO in STK

I'm trying to design a three-stage rocket ascent flight trajectory to LEO using AGI's Software SKT but I'm in trouble. Could anyone help me with designing it?
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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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### Calculate velocity vector of hyperbolic trajectory

I am writing a little 2d space program and I need to calculate a velocity vector for my program. I already have my elliptical orbits working well but once the eccentricity of the orbit goes over 1 the ...
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### How to calculate the amount of lunar regolith needed to reduce solar radiation in an area on earth by 0.2% or 0.5%

I am working on a climate change that doubles as a lunar infrastructure project. I am wondering if anyone could direct me to resources or help me answer the question of how much regolith scattered ...
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### Preliminary Orbit Determination Packages

I have been looking for free orbit determination packages that take in 3 sets of RA,DEC and time, along with observation position and spits out a preliminary orbit estimate. Even if it is a Matlab/...
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### How much delta-v is expended to get <out of the atmosphere>

How much delta-v it's spent in getting up to avoid the air drag once in orbit?
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### Launch Vehicle LM2D

As it is well known, the circularization of orbits needs at least 3 stages. How could the Chinese launch vehicle LM2D circularizes its orbit with only 2 stages?
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### What is the speed of ISS relative to ground surface?

Is it 7660 m/s or (7660-460)m/s? If it is the former then the ISS orbits about the Earth at 8120 m/s. I think it should be (7660-460)m/s relative to ground based on this orbital period formula, T=...
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### Why would ISRO's MOM-2 Mars orbiter mission's apoarion already be decided in such an early call for proposals?

ISRO's announcement Announcement of Opportunity (AO) for future Mars Orbiter Mission (MOM-2) says in part: It is now planned to have the next orbiter mission around Mars for a future launch ...
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### How can I calculate Mean anomaly from True longitude?

So, I have - TLE data - Reference frame: QMOD - Type: Osculating - Semimajor axis - Eccentricity - Asceding node - ...
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### Is kinetic bombardment from NEO fragments now practical with current technonology?

Everything I know about orbital mechanics I know from Kerbal Space Program, so this may be a dumb question. Using (possibly wrong) math, it looks like that even for the lowest delta-v (to Earth) ...
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### Would a Mars flyby be possible on a transfer orbit from Saturn's moon of Titan to Earth?

So, I am trying to calculate whether a transfer burn from Saturn's moon of Titan to Earth would involve a Mars flyby, assuming I have the burn start on 2 March, 2025 and arrival on 19 March, 2031. ...
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### $\Delta V$ to aerocapture - reconciling conflicting data

I'm working on some delta-V calcs for both Hohmann and non-Hohmann transfers, but the data I'm getting is conflicting. While I'm looking for much broader applicability than transfer to Mars, since ...
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### Saturn's Pan and Prometheus orbital resonance

Is it possible for a small object (such as a manned capsule) to realize a maneuver using the orbital resonance influence of Saturn's moons Pan and Prometheus?