Questions tagged [orbit]

Questions regarding the mechanics or attributes of objects falling 'around' other objects, thereby orbiting them.

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28 views

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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Confused about SGP4 implementation published by celestrack

I was trying to understand how SGP4 computes the propagated position I had a look on the original publication paper but i have not found a satisfactory answer. So I had a look to the Matlab ...
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135 views

Is it possible to buy a used geostationary telecom satellite and tow it to lunar orbit?

Though unlikely to be practical, would it be at all possible to buy an older, used geostationary telecom satellite and move it to an orbit around the Moon? What are the challenges to the move itself? ...
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Is it possible to achieve a perfectly circular orbit?

Is it possible for a spacecraft to achieve an orbit around a celestial body that has no orbital eccentricity at all? The smallest orbital eccentricity of a natural satellite is that of Triton's orbit ...
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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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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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37 views

Differences between Semi Major Axes and ECF Magnitudes for Circular Orbits with J2 Perturbation

I have simulated (in STK) a satellite at near circular orbit, near-equator, with Brouwer Lyddane Mean Long SMA of 6935.31km, inclination 10 degrees, and eccentricity of 0.0001875 (these are solved-for ...
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128 views

Orbit Elliptical Fitting

Question: Given a set of XYZ (3D) coordinates in the Earth-fixed frame, after converting them to the inertial frame, how do I perform orbit fitting in the least-squares sense (meaning minimising all ...
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Are there any related groups of satellites that are in a line of 6 or more in a row?

02/03/20 0450hrs, in Bradford, West Yorkshire, Uk. I saw a satellite going across the sky, it was not too bright and was followed by another and then 4 more they were equally spaced. I would say they ...
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Calculating trajectories of payload fairings

How can I calculate the trajectory of a payload fairing assuming that I have several data points of height or speed of rocket? I'd like to know which topics are necessary to study this.
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What calculations should I do to go from LEO to the moon with an ionic motor?

my question is, what calculations should I do to be able to go from LEO to the lunar orbit? If this were done, two of these thrusters would be used https://www.cubesatshop.com/product/ifm-nano-...
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Are Planet orbits available to download in some vectorial format file?

I would like to work with solar system planet orbits in a Geographic Information Software like QGIS, so: Are available to download the orbits of solar system planets in some vector format?
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What are the biggest challenges for high altitude rail-gun launch systems?

Use a maglev railgun for initial acceleration - in a new, hyperbolic tunnel facing eastward - this exits from the burrowed -undergrade- track to Equadors' Mt. Chimborazo peak - (a mountaintop both 6 ...
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Is an Earth synchronous (?) polar orbit possible?

I don't even know how to exactly ask this question. A coworker is doing some experiments on a data visualization software and he has some test data showing fake telemetry from a simulated satellite. ...
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Determine if two orbits cross paths

I'm trying to determine which orbital object will have the most close calls with another object. I've gotten the full TLE catalog from Space-Track.org, and using poliastro python package have ...
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1answer
133 views

Space and Newton laws

I've read some articles which explain that we can't totally rely on Newtonian gravity concepts for understanding the motion of objects in space. My question is how the use of relativity helps us to ...
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1answer
102 views

Geocentric latitude and longitude of sub-satellite point

I was trying to derive the expressions for the geocentric latitude and longitude of the sub-satellite point using Keplerian elements. The final equations connecting the combination of the Keplerian ...
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1answer
254 views

Why don't spacecraft get left behind once in deep space?

On earth, I know that if I throw a tennis ball straight up while in a car, it comes straight back down thanks to Newton's first law. The ball, the air in the car, and myself are all moving at a speed, ...
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1answer
106 views

How to identify an object in orbit last night?

I saw an object last night (November 24, 2019) in the sky that was rather unusual and am curious about what it might have been. It had the luminosity and speed of movement across the sky (generally ...
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1answer
108 views

Could we reverse gravitational slingshot a fast object to slow it down and capture it in an orbit?

I have heard of plans to capture an asteroid in an orbit around the earth, to have it close by so that we could study it more easily. Such objects can have very high velocities, (I assume) possibly ...
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How did the USSR track Gagarin's Vostok-1 orbital flight? Was tracking capability an issue in the choice of orbit?

For the USA's Mercury flights, a number of tracking stations were installed around the globe. John Glenn's first orbital flight was tracked with them, plus a number of ships. (Tracking stations used ...
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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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328 views

What is the gravitational acceleration of the Sun?

What is the gravitational acceleration of the Sun? I've seen numbers such as 274 m/s2, but that doesn't make sense to me seeing that relatively weak sources of spacecraft thrust such as Electric ...
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82 views

How to calculate 𝛥𝑣 that required to change orbit with same radius but different inclination?

How could I calculate the total 𝛥𝑣 required to change the inclination of a Geostationary orbit to another circular orbit with an inclination of 30° and the same radius? (The sidereal day is used for ...
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302 views

What information can I get if an elliptical orbit intersecting a circular orbit of radius 𝑟 and velocity of ellipse is equal to velocity of circular?

How can I approach solving the question below? Consider an elliptical orbit intersecting a circular orbit of radius $r$ as shown below. If $v_{ellipse} = v_{circular} = v $, find: True ...
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2answers
549 views

Velocity of a rocket needed to get to Mars

At 2:16 in this video, Don Pettit says he used the Rocket Equation to determine the velocity of the rocket needed to travel to Mars, which was 16 km/s. I am not sure as how he did it though, and was ...
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How does a Spacecraft change its orbit?

I am a high school student. I saw the latest Indian spacecraft "CHANDRYAANN 2", which was in orbit around the Earth for 14 days..... I am so curious to know how a spacecraft changes its orbit. I ...
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171 views

Do satellites in orbit undergo translational motion or rotational motion, when initially they are not given any additional spin?

Regarding the proposed duplicate: Thought the proposed duplicate has a similar titIe, I have read those answers and this question requires a different answer. We know satellites orbit around Earth, ...
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When will ISS return to approximately the same projected location on Earth's surface?

The ISS sailed over my country, Sri Lanka on the eve of yesterday (14th October), and there was some news coverage on the event. While the reporting wasn't particularly scientific or even factual (I'm ...
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How to deteremine the angle between Sun and 2 probes?

I have the orbital position and velocity and the orbital parameter of 2 spacecraft at LEO, how to define the angle between Sun - Probe 2 - Probe 1 in ECI frame (If you imagine at a point sun then ...
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93 views

Issue with SGP4 modelling from scratch in MATLAB

I am trying to develop the code from this source , this research paper and from this too as same as bibliography of that aforementioned source. So, here as you can see at page 14, they have defined ...
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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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How does the orbit of the Voyager and New Horizons probes manage to get into interstellar space?

I understand that every probe launched has been launched into an orbit. The further you want to go into the solar system, the faster it needs to be moving. And everything orbits the sun until it finds ...
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What is the closest distance SpaceX's Tesla Roadster (Starman) will ever be to Mars?

Elon Musk's own personal Tesla Roadster launched on the Falcon Heavy in November 2018 and unfortunately overshot the orbit of Mars. This short animation shows the trajectory of SpaceX's Roadster. It ...
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When calculating the future orbit of an artificial Earth satellite, is the Moon's gravity significant or insignificant?

Imagine a mathematician is plotting the future orbit of a satellite to be launched and put in orbit around the Earth. When they are making their calculation, is the moon so far away and the ...
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115 views

Do satellites inject into a Hohmann transfer orbit in Low Earth Orbit or in Solar orbit?

Lets say we have a satellite wanting to go to Mars. Do satellites such as MAVEN inject into a Hohmann transfer orbit while in Earth's orbit, or do they go out of Earth's Sphere of Influence into solar ...
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Where in orbit was Michael Collins when the LM landed?

In the NPR podcast On Apollo 11 Anniversary, A Former Crew Member Reflects On The Lunar Trip Scott Simon interviews Michael Collins. Near the beginning is this exchange: SIMON: We asked the man who ...
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A spacecraft is travelling at X units per hour. But relative to what exactly? Does it depend on orbit? How?

If I am walking, the ground is stationary, and I move X units/hour relative to the ground. If I am in low-earth orbit, then I am still moving X units/hour relative to the ground, only its a much ...
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157 views

Can a Space Telescope orbit so it was always in the shadow of the Earth?

Imagine you have a space telescope that had temperature sensitive instruments. (Like the Spitzer Space Telescope). In order to maintain a cool temperature - you want it always to orbit in the shadow ...
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980 views

Why does the eccentricity vector equation always equal -1?

This is the eccentricity vector equation, $$e=\frac{1}{\mu}[(v^2-{\mu \over r})r-(r \cdot v)v]$$ $$e=|e|$$ Now this equation is written differently from many different sources but they essentially ...
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Orbiting clock visible with the naked eye

Does anyone remember from the 1980s or possibly early '90s in the UK news a (serious) story about contructing a huge orbiting clock so that people would be able to look up at the sky to read the time ...
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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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How could a satellite follow earth around the sun while staying outside of earth's orbit?

I'm wondering if its possible for a satellite to follow earth around the sun while staying outside of its orbit. I wondering for the sake of space based solar infrastructure or just something ...
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379 views

Why was the Energia’s payload capacity to lunar orbit greater than its payload capacity to geosynchronous orbit?

The Energia rocket, developed in the 1970s and 1980s to launch the Soviet Buran space shuttle, had the second-highest payload capacity (100 tonnes to LEO) of any rocket ever flown (and the highest-...
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121 views

Tiny orbital body detection

What technology would be required to detect a coconut-sized sphere in Earth orbit, at the average altitude of communications satellites?
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Special Case Constellation Analysis Approach: Walker Constellation with Circular (e = 0) orbit in LEO

I am familiar with the general approach to propagate orbits using orbital parameters, and how to account for basic J2 perturbations. I am looking to perform some analysis on large walker ...
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108 views

PIR application as a sun sensor

Is there any history or merit to using a PIR (Pyroelectric ("Passive") InfraRed Sensor) as a sun sensor for determining the attitude or position of a Satellite?
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122 views

Recalculate Orbital Elements after a ΔV

I would like to write a program able to simulate a keplerian orbite given an initial position and velocity (r0, v0) and able to manage accelerations in different directions. To simulate the orbit, I ...
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4answers
216 views

How many stages needed for a launch ? How to plan a launch

I am looking to find out how many stages are needed to reach a certain orbit. I came across equations to compute the height reached by a stage over a certain time; however, I couldn't find material on ...
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766 views

How precise must a satellite's orbit be?

I was thinking about the question on solid upper-stages and my feeling that a liquid upper-stage would allow a more precise orbit. But... how precise does an orbit actually have to be? I guess I mean ...

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