Questions tagged [orbital-mechanics]
Orbital mechanics (also called astrodynamics) is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft on an orbital or escape trajectory. For the movements of celestial bodies, use [celestial-mechanics], not this.
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TEME state vector to TLE orbital elements
I was looking at time series of some TLE parameter(semimajor axis, inclination, etc..) and I wanted to how those parameters evolve between measured time points.
So i decided to feed TLE element to ...
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What causes a satellite's orbit to decay?
Why do orbits of satellites orbiting at sufficient speed, far beyond the Earth's atmosphere, decay if there is no atmospheric drag? What drag is applied on the satellites at that altitude?
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Approach to Interplanetary Transfers in GMAT
I hope to find a straightforward process for designing interplanetary missions using the General Mission Analysis Tool (GMAT). This would involve calculating the required initial state, timing, and ...
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How close do gravitational 2-body hierarchy levels get?
Due to very few 3-body arrangements being stable (this question thus excluding co-orbital objects like trojans), objects in space usually arrange themselves in a hierarchy of 2-body systems. When the ...
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Is it possible to create an analytical ephemeris from raw position and velocity of a Body?
I would like to have an analytical ephemeris for various bodies of the solar system (planets, natural satellites and asteroid). I have at my disposition spice kernels from which i can extract position ...
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How did theorists determine that the atmosphere attenuates enough to support unpowered orbits?
Before getting rockets into space were scientists certain that the density of the earth's atmosphere would decrease with height enough to permit low earth orbits? If so how was that determined?
(If ...
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Could a “solar gravitational synchrotron ” use solar thermal rockets to "powerslide" spacecraft out of the solar system?
Could a “solar gravitational synchrotron ” use solar thermal steam rockets to launch spacecraft out of the solar system?
Solar thermal steam rockets https://en.wikipedia.org/wiki/Steam_rocket have ...
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Negative elevation angle
What does it mean to have negative values of elevation angle from the low-Earth orbiting (LEO) satellite? Can the negative values of elevation angle be useful?
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Distance between a satellite and an orbit
I would like to compute the distance between a satellite and a specified orbit. For instance, for an orbit at 897 km altitude, 0 degree eccentricity, 99 degree inclination, and RAAN of 0 degrees on ...
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Propellantless propulsion in gravity field
I have a proposal for a following propellantless maneuver. It is propellantless in sense that no mass is lost from spacecraft.
It is not reactionless as spacecraft interacts with planet through ...
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What use (if any) does the "empty focus" of an elliptical orbit have in orbital mechanics?
The 2 bodies in a 2-body system orbit around their common barycenter, which is located at the common primary focus of both their orbits. The empty foci don't seem to have a job in celestial mechanics.
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Can Tisserand's parameter be modified to correct for perturbing eccentricity?
Tisserand's parameter is an "almost" conserved quantity in the CR3BP, even after flybys (useful for identifying asteroids).
$$T_P = \dfrac{a_p}{a}+2\sqrt{\dfrac{a}{a_p}(1-e^2)}\cos(i)$$
It ...
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Center of gravity changes against the vertical axis of the orbital plane: Help me open some minds with the math on the behavior of objects in orbit [closed]
Edit:
Ok, thank you all for your input. I will attempt to clarify the question now based on the additional information I was able to garner from your comments.
I believe the math formula I am looking ...
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Does a space elevator ruin most satellite orbits?
A space elevator would offer a direct connection between the surface of the Earth and geosynchronous orbits. While the concept has several severe problems, according to my understanding of orbital ...
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Calculating momentum exchange of rotating skyhook
I am struggling to understand how momentum is exchanged during a rotating skyhook's interaction with a payload, during capture and after release. I am a layman in physics, please be forgiving if I've ...
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Does the spin rate of an object have any effect on something orbiting it?
For example, if the Earth - by some unknown force - stopped spinning, would the orbit of the Moon be effected at all? Its not a perfect example because Earth's gravity is not uniform - it has ...
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What is the relationship between the radius of the Hill sphere and escape velocity?
I'm currently working on a video game that will make use of a heavily simplified patched-conic model of the Solar System.
I was wondering about some discrepancies between my own calculations as well ...
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Does every celestial body orbits something? [closed]
Pretty much the title is the question. Lets take the massive blackhole of our milky way does this black hole orbit something?
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What is the slantRange of a GPS
How can I know the slantRange of a GPS in the aer2ecef function
thanks
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Meaning of superscript letters in sidereal time calculation
I'm following along with Dr Kelso's columns on CelesTrack and I've come across this equation.
$$θ_g(0^h)=24110^s.54841+8640184^s.812866T_u+0^s.093104T_u^2- 6.2\times10^{-6} T_u^3$$
As you can see, ...
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TEME to J2000 conversion algorithm
I've asked a few questions to do with this in the last day or so and received answers that have led to more questions...
How to use David Vallado's AstroLib to do reference frame conversions
https:...
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How to use David Vallado's AstroLib to do reference frame conversions
Given a Keplerian Orbit description such as that in here:
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Get fully defined orbit from space-track.org SATCAT
My question is related to this one on Physics SE. Admittedly, I'm somewhat preempting the answer over there being "you can't, there's a missing parameter", so if it comes back that you can ...
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How can I calculate GPS satellite's Latitude and Longitude if I have the elevation and the azimuth
Please tell me how I can calculate a GPS satellite's latitude and longitude if I have the elevation and the azimuth angles.
I am using a septentrio GPS receiver.
Thanks
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Help with fictional scenario: trapped in Lagrange Point orbit
I'm a full-time screenwriter trying to create a realistic sci-fi scenario, though not necessarily a hyper-realistic one like those in The Martian. Think more along the lines of pseudo-scientific ...
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How would I calculate the resulting orbit of Dimorphos around Didymos A after the DART mission?
I have been trying to find a way to calculate how the DART mission affected Didymos A, independent of NASA's findings. I found one answer to this question, but it was as if they ignored Didymos A and ...
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How close can a spacecraft get to the Sun if it is limited solely by passive cooling?
The Parker Solar Probe’s trajectory will take it within 8.5 solar radii of the sun’s photosphere. Its instruments, hiding in the shadow of the alumina-coated composite sun shield, will bask in 29 °C ...
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How would one obtain the longitude of satellite at the apogee?
I know that apogee longitude is a design point in Molniya orbits. Given the classical orbital elements, how can I find this value?
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Why does the point of burn on an orbit stay at a constant altitude?
I am having trouble understanding why the current location you are at in an orbit remains unaffected when performing an orbital maneuver.
As an example, if I want to raise the apoapsis of my orbit (...
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What is the reason Starlink satellites took 4 days to re-enter during the accident on February 2022?
I am reviewing the incident that knocked out 39 Starlink satellites earlier this year.
As I explain in this thread, there was a modest magnetic storm on the 3rd of February, which increased ...
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How to place a satellite in retrograde heliocentric orbit?
Imagine a mission which requires a retrograde heliocentric orbit. How could this be achieved? a direct launch would require ridiculous delta-v.
There was a similar delta-v problem placing Ulysses in a ...
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Minimum number of satellites to achieve 24 hour coverage at LEO for a single point
If I want to cover one single point on earth with 24 hour coverage using LEO satellites, how many are needed at minimum and what would be their orbit
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Is there an accepted method to compare orbits?
I'm wondering if there is a universal or accepted way to compare orbits.
For example, I have a spacecraft orbiting Earth and it is slowly increasing its altitude every time it passes a local midnight ...
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How can you calculate a Hohmann transfer orbit but ending at the same orbit with a time difference between orbits?
How can you calculate a Hohmann transfer orbit but ending at the same orbit, just having changed the time?
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How to calculate initial Rotation Matrix/ Euler Angles/ Quaternion for IMU data (gyroscope and accelerometer)?
I am trying to develop a code to track vehicle using GNSS/GPS data (NMEA) and IMU data (Gyroscope x,y,z; accelerometer x,y,z) i.e. dead reckoning using kalman filter.
I know there's enough literature ...
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At what point did Artemis 1's Orion execute the orbital inclination change for its return transit?
Orion is returning to Earth with a marked orbital inclination compared to its Lunar Distant Retrograde Orbit (DRO).
Orbital inclination changes require a great deal of delta-v, and Orion is on a tight ...
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Delta-V vs Time equation for interplanetary transfers
I'm working on a project for my high school math class and my research question is about time vs delta-v budgets for an interplanetary transfer (e.g. earth to mars). I understand this is a relatively ...
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Why is the Orion capsule using 2 burns to transfer from the moon back to earth instead of one?
I was reading an article about how the Orion capsule just did the first of two burns that it will use to transfer out of its lunar orbit and back to Earth.
I understand the phenomenon of a gravity ...
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How can I find Inclination and Longitude of ascending node for the Moon on JPL's Horizons?
To answer the bountied question "Puzzler: Precisely what maximum distance from the Earth did the Apollo 13 astronauts achieve? ", I have to know the Inclination and the Longitude of ...
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Osculating conic orbital elements: Comparing SPICE's oscelt to MATLAB's ijk2keplerian functions
I have been using the SPICE Toolbox and wanted to derive orbital elements from a state vector $X$ in ECEF coordinates [1] in order to define a circular orbit around Earth. To do so I need first ...
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What is the velocity of the ISS relative to the Earth's surface?
This was asked once before, but I believe there was no clear answer given and accepted.
The ISS has an orbital period of 92.9 minutes, or 5574 seconds. If it were in a completely equatorial orbit, ...
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How to find the SMA starting from a given repetition factor?
I need a help for an orbit design problem.
My constraint is that the height is 480 km, the repetition factor has to be Q = 245/16 and the orbit must be sun-synchronous. I would like to find the SMA ...
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Rewriting the equation of motion as a system of first order differential equation
I am required to rewrite the equation
$$\ddot{\mathbf{r}} = - \frac{\mu}{r^3} \mathbf{r}$$
as a first order differential equation. How do I go about doing this?
I understand how this equation was ...
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Use ECI cordinates to plot orbit in three.js
I am using satellite.js to get ECI coordinates from TLE data. Now my first question is can ECI coordinates be used to plot satellite orbit as shown here.
If yes then how can i do that in three.js?
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Sanity check on coordinate systems
I've seen a few different answers given, so I want to specifically address the nit-picky pieces.
First, when calculating the relative position of two objects in the UVW/RIC frame, should the ...
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Solution to two-body problem in orbital mechanics for r(t) and theta(t), rather than r(theta)?
I have written a simple numerical integration code to calculate the orbits of two planetary bodies orbiting a star, in order to calculate the transit-timing variation for one body due to the ...
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Two different Hill equations for space rendezvous
I have stumbled upon two variations of Hill’s equations across numerous scientific journals:
Why are the mean motion’s positive and negative signs of these two Hill equations reversed? And are these ...
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Could a space elevator launch a payload to a solar orbit?
From my understanding, a practical space elevator would require a large center 'station' in geostationary orbit that the cable is attached to, and some form of counterweight on the other side, ...
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Orion re-entry velocity: Why is it higher than Apollo?
Title says it all. I am puzzled why Orion will be traveling faster than Apollo.
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Why does the the Artemis I translunar flight (have to) last 6 days while the Apollo fights to the Moon lasted only about 3 days? [duplicate]
Does the Artemis I flight to the Moon have to last so long compared to the about 3 days long lasting Apollo flights because the Orion spacecraft has to enter into a distant retrograde orbit (DRO) ?
Or ...
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