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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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Why does this satellite collision debris field look like a big “X”?

This answer to the question Whats the protocol if two satellites collide? shows the image below, and I don't understand the shape. I would have expected two "jets" of debris, each projecting roughly ...
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How do you find the temperature of an orbiting aluminum sheet 10x10 cm

I'm trying to find the temperature of a CubeSat in orbit at 140km. I'm trying to use the Stefan-Boltzmann law but don't know how to incorporate the energy from sunlight. I'm using this as a check for ...
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Where can I find examples of orbital state vectors?

I'm currently trying to write a program that can calculate orbital trajectories. The goal is to take any orbital state vector (position, velocity) and convert it into Keplerian orbital elements, or ...
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Does the arrow in this SOHO trajectory animation point heliocentric prograde, or towards the Sun?

This answer links to this NASA page. The first video shows the two STEREO spacecraft use two and three passes by the Moon to leave Earth orbit and enter into an orbit around the sun. Below is a GIF ...
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How would 2 JWSTs make stereo pictures?

Could 2 JWST be launched in opposite directions to provide stereo vision? Would a stereo picture provide any benefit? https://space.stackexchange.com/a/35402/18879 Related: How will JWST manage ...
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Details about traveling from EM-L2 to SE-L1

Would the optimal time to launch be when the Moon was on the opposite side of the Earth from the Sun? What direction would be optimal leaving EM-L2, radially away from the moon? Is the last line of ...
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+100

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 would molten or liquid metal be transported in open space? [closed]

How to transport a ball of liquid, molten metal nearest to the Sun possible? It must be close to the Sun for the metal to stay molten. However, to stay safely cool enough, the spacecraft must always ...
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281 views

Apollo 11 space mission Lunar Orbit Insertion

I'm doing a basic analysis of the trip to the Moon. I've estimated the speed as follows: ...
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How does mass exchange affect the mutual orbit of two bodies?

If a pair of bodies orbit around their center of mass, and then mass is removed from one of them and transferred to the other, this will change their orbits. Total mass is conserved, but the ...
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what are various best practices/processes associated with orbit change manoeuvres of LEO / GEO satellites?

Suppose a satellite was supposed to burn X% fuel reduce Y% mass to gain delta V and change to different orbit in time t. But something is faulty with its propulsion system so it's burning more fuel to ...
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Could JWST stay at L2 “forever”?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
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How will JWST manage solar pressure effects to maintain attitude and station keep it's unstable orbit?

The James Webb Space Telescope presents a huge reflective cross-section to the Sun's photons, and this can generate both torque and thrust. How will JWST manage solar pressure effects to maintain ...
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Just how record-setting was the launch-to-docking time of the April-4-2019 Progress resupply mission?

Digital Trend's article 3-plus-hour supply trip from Earth to International Space Station breaks record mentions that this was even faster than the typical "fast-track" Russian launch-to-docking time ...
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Will a spacecraft accelerate in a gravitational field via the use of a powered rotating mass?

I believe that a powered rotating mass on board a spacecraft should result in the spacecraft being propelled in a continuous increasing velocity towards the source of the gravitational field. To help ...
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Most preferred coordinate system for Launch vehicle trajectory

To integrate the equations of motion for a launch vehicle trajectory to the orbit, which is the best coordinate system to consider of the following two: Rectangular with Earth-centered inertial frame ...
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+200

What was Sutton talking about? How to “obtain small accelerations by taking advantage of difference in gravity as a function of altitude”?

Sutton and Biblarz's Rocket Propulsion elements says in Chapter 1, section 1.2 (editions 7, 8, 9, possibly earlier as well) that: Totally different methods of producing thrust are used in ...
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Finding Earth-Centered Coordinates of Periapsis

I am currently writing a program that accepts a state vector, calculates the corresponding Keplerian ellipse, and then draws the ellipse. But I'm stuck at the following point. I currently need some ...
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How can I change plane (inclination and OMEGA) during a bielliptical transfer?

I'm trying to minimize deltav in a transfer between two elliptical orbits. The 'standard' strategy the professor provided consists in a change of inclination and RAAN and then a bielliptical or ...
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4answers
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Is GEO redundant (Geo- and Earth)? Would we call a Lunasychronous Lunar orbit LLO?

I think the title of the question Is it possible to establish a synchronous lunar orbit without using Lagrange points? is absolutely clear; it's an orbit around the Moon that is synchronous to the ...
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1answer
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How to find T₀ and other parameters from a TLE to calculate an approximate mean anomaly?

The equation for mean anomaly is $$M = \sqrt{\frac{\mu}{a^3}} (t-T_0)$$ How could I extract information from a TLE in order to calculate a mean anomaly? Would I use this equation, or something ...
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Is it possible to change to different orbit inclinations with a simple push?

Supposedly launching to different orbital inclinations is quite difficult, with launchers trying to launch from different launch sites to using mid air launches to avoid geographic restraints. If a ...
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Stabilizing Mars wobble, before terraforming

So, Has anyone addressed the wobble and any possibility of doing the mathematics of how our Moon stabilizes the Earth, based on it's relative size and shape, and any other variables, and try to ...
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2answers
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Is a solar free-return trajectory possible?

I'm coining a new phrase: "Dyson circuit". Is it possible, with current solar orbital capabilities (see Parker Solar Probe), to drive artificial satellites in a free-return trajectory around the Sun? ...
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Does it take more energy to get to Venus or to Mars?

Let's assume we use the ideal positions of those planets relative to Earth for launch. And let's assume the spacecraft is launched from the same place on Earth. Also let's assume the goal is to get ...
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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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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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Could a steam Engine outperform other electric producing devices in space? [closed]

What would be the Specific Impulse of a steam-based propulsion system like this model in space? Are there any types of engine that works this way? Could 2 tanks be designed to rotate slowly in space ...
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Calculation of V1 (orbital speed) during ascent

I am studying instrumentation of NASA's Orion spacecraft, and there is a readout for V1 (I am assuming this is the "first orbital velocity", for circular orbit), and it seems to be in small decimals. ...
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3answers
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Why is delta-v the most useful quantity for planning space travel?

Many of the questions and answers on this site make use of the concept of delta-v. Is there an easy to understand the reason why delta-v, the magnitude of the change of the velocity, $|\mathbf{v}|$, ...
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1answer
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How are gravity coefficients calculated?

I was reading Satellite Orbits - Models, Methods, and Applications by Montenbruck & Gill and was trying to use the equations in it to calculate $J_2$ as used in the GEM and JGM gravity models. ...
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What is the smallest body in which a sling shot maneuver can be performed?

This question asks about the smallest sling shot maneuver performed. What was the smallest intentional, acknowledged slingshot maneuver? I'm asking how small of an object be to perform a sling shot ...
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What types of engines are able to go from Earth orbit to Martian orbit? [closed]

What engine is the most efficient in fuel and/or time to go from Earth orbit to Mars orbit and back again that are not capable of launching from the ground?
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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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1answer
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Rendezvouses in halo or lissajous orbits

If a spacecraft was in an EM-L2 halo/lissajous orbit, and another craft would was going to approach EM-L2 a few days later, could they rendezvous immediately or is there a limitation when the second ...
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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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Astrophysics on “The Martian”

In the movie the martian what was the purpose of the hermes crew in blasting a part of the ship? Was that explosion on the front or back of the ship? After the explosion what happened to the speed ...
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Do horseshoe orbits have anything to do with Lagrange points? Do words fail us here?

I said (2010 SO16 is associated with Lagrange point L3 but wanders so far behind and ahead of it that the orbit is called "horseshoe"... and the comment was made: Not really. L3 is unstable. ...
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How to calculate angle in elliptic orbit?

I would like calculate angle in elliptic orbit ZCP at any time, where: Z (position of periapsis), C (center of ellipse), P (current position of planet). I find topic, where is picture (in accepted ...
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Orbit, circularizing, apogee/perigee

First - my question: After the orbit insertion, in the coast stage, and assuming perigee is out of the atmosphere, and neglecting any external forces and influences - is the orbit now "fixed"? As in, ...
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3answers
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How fast can an orbit exist in the solar system?

How fast is too fast to stay in orbit around any particular large body in the solar system?
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What is the order of magnitude forces due to Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare?

What in order of magnitude does pressures vary in LEO due to diamagnetic repulsion of Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare on an ideal satellite? Is there any ...
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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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If we can reduce travel time to Mars below the Hohmann standard, would we still use the same launch window?

If we can reduce the travel time to Mars below the Hohmann transfer orbit's typical 258 days, would we still use the usual Hohmann launch window or delay launch accordingly? For example, if we ...
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2answers
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Launch profile autopilot

I'm new here, and I am delighted this forum exists! I'm working on a spaceflight simulator (FSX SpacePort) and currently, developing automated guidance module (I guess, a space autopilot). The ...
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How far will the debris cloud from Hayabusa-2's touch-and-go sample recovery travel around Ryugu? Will any have escaped to heliocentric orbit?

HAYABUSA2 MOMENT OF TOUCHDOWN This animation, extracted from a longer video, shows the moment of Hayabusa2's 21 February 2019 touchdown on asteroid Ryugu. JAXA Source: Planetary Society's Watch ...
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How do orbital spacecraft calculate reentry?

For a given spacecraft, in a given LEO orbit, assuming you have all the required data, how do you choose the needed burnout speed and timing (or position in orbit), in order to reach a certain point ...
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Why does Starman/Roadster have radial acceleration?

Discussion in chat pointed out that the SpaceX Roadster or Starman has a Marsden A1 coefficient. From solution 10 in Horizons: ...
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How do you determine the orbit of a satellite around some planet of unknown mass?

I am working on project where I want to derive the orbital equation for a satellite of Mass M, orbiting around a planet of Mass P. I want to do this with these unknowns first to then apply the orbital ...
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Walking in a rotating spacecraft and Newton's 3rd Law of Motion

I am wondering how Newton's 3rd Law of Motion would apply in the case of a man walking the length of a rotating spacecraft. Please reference the drawing below. Say that there was a spacecraft ...