Questions tagged [orbit]
Questions regarding the mechanics or attributes of objects falling 'around' other objects, thereby orbiting them.
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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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34 views
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 ...
2
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2answers
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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3answers
1k views
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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2answers
124 views
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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0answers
34 views
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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0answers
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 ...
4
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1answer
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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2answers
127 views
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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1answer
72 views
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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1answer
115 views
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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57 views
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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3answers
4k views
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 ...
13
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2answers
2k views
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. ...
2
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0answers
40 views
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 ...
2
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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 ...
2
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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, ...
2
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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 ...
1
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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 ...
33
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4answers
6k views
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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0answers
53 views
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 ...
2
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3answers
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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1answer
82 views
How to calculate 𝛥𝑣 that required to change orbit with same radius but different inclination?
How could I calculate the total š„š£ required to change the inclination of a Geostationary orbit to another circular orbit with an inclination of 30Ā° and the same radius? (The sidereal day is used for ...
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2answers
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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4answers
4k views
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 ...
7
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2answers
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, ...
3
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0answers
40 views
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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1answer
42 views
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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1answer
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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0answers
34 views
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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2answers
126 views
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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2answers
187 views
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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2answers
158 views
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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2answers
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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1answer
178 views
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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3answers
438 views
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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1answer
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 ...
4
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1answer
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 ...
2
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0answers
117 views
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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33 views
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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5answers
3k views
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 ...
3
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2answers
379 views
Why was the Energiaās 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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1answer
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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0answers
38 views
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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1answer
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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0answers
122 views
Recalculate Orbital Elements after a ĪV
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 ...
5
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1answer
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 ...
