Questions tagged [orbit]

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

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Could we make space roads? Like a space elevator between planets?

We hear a lot about space elevators that could place something in orbit, but what about a space road between planets? Suppose you had a long tube or flat road placed between Earth and Mars by chemical ...
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1 answer
57 views

What are the factors affecting a satellite's Repeat Ground Track period?

I understand the Repeat Ground Track (RGT) period of a satellite will be affected by its altitude. A similar post: How Do I determine the ground track period of a LEO satellite, describes a simple ...
2 votes
3 answers
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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 ...
2 votes
2 answers
1k views

How did the Lunar module reached orbit speed?

How does the lunar module of Apollo 11 reached an orbit speed of 1600 meter/second in order to rejoin the CSM (Command/Service Module)? Additional question, Where are the Oxygen & Fuel tanks of ...
2 votes
3 answers
233 views

Can we more accurately predict orbits or measure position?

Imagine a satellite of known mass, orbiting the sun outside the Earth-Moon system. Assuming that we made a serious attempt to measure both it's position and attempted to predict it's orbital path, ...
1 vote
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Is my code correct to get six Keplerian parameters?

Is my code correct to get six Keplerian parameters? ...
3 votes
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How bad is a non-Lagrangian Point orbit?

I am no expert on space physics, just an interested amateur. I've been searching for a few weeks and having a hard time gaining insight on this question. Phrasing the question more specifically: how ...
12 votes
1 answer
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How were Wikipedia's orbital simulations made?

Pretty simple question; what software is used on Wikipedia to make these simulations? Some examples below:
12 votes
5 answers
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Would Starship be able to lift mass to orbit (both low and geo-stationary) cheaper than "any" space elevator?

A comment to an answer to a question about Mars missions stated that using Starship to launch mass to orbit would be cheaper than a space elevator. I didn't imagine that. I know that space elevators ...
4 votes
1 answer
138 views

What is the current state of the art in converting between mean and osculating orbital elements?

I want to implement algorithms to convert from mean to osculating elements, and vice versa. I've been digging through Vallado's text (fourth edition), and under ...
8 votes
3 answers
1k views

What can one do as an individual to help support the development of skyhooks?

In my recent research on the potential of a SkyHook, I've found a startling gap: it seems like no one is actively pursuing this technology. Many, including myself, believe that this could be the ...
1 vote
1 answer
103 views

MATLAB Simple Elliptical Orbits with J2 perturbation and drag

For some reason I need to build a Elliptical Orbits satellite dynamic model by myself, in here I am using MATALB. The model its fine before (I think the J2 effect part works well) I add drag effect on ...
3 votes
1 answer
624 views

Vis-Viva equation applied to Earth

We know that the Vis-Viva equation is given by: $v=\sqrt{G M\left(\frac{2}{r}-\frac{1}{a}\right)}$ If I plug-in the values for Earth (the mass is obviously that of the Sun): $G=6.6743 \times 10^{-11} \...
10 votes
1 answer
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What is the name of this specific, popular MEO orbit? [duplicate]

While browsing a space object visualisation service, AstriaGraph, I see a large number of objects occupying a specific MEO orbit, and I want to understand the name and purpose of this orbit, and what ...
1 vote
1 answer
105 views

Equivalent Vis-Viva equation but for acceleration

I know that thanks to the Vis-Viva equation, knowing the elliptic parameter of a celestial orbiting object we can get its speed on any point of the orbit. But what about the acceleration? Is there an ...
15 votes
3 answers
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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 ...
11 votes
5 answers
1k views

In circle orbit, give a delta V to a satellite, how to find final orbit altitude?

I think this is a very very simple question for me, but unfortunately I cant solve it... A satellite is orbiting in a circular path at an altitude of 600 kilometers. If the satellite is capable of ...
2 votes
1 answer
266 views

Converting Keplerian Orbital Elements into 2D State Vectors in Unity C#

I have done an extensive amount of research into this topic, but am really struggling to implement the math necessary to pull this off correctly. Just for some context: I'm trying to create a semi-...
7 votes
1 answer
573 views

Definition of "stable orbit"

I often struggle with the term "stable orbit" for objects in earths sphere of influence, since all real orbits are affected by disturbing forces. Sentences like: It is not possible to ...
2 votes
0 answers
181 views

Escaping Earth - how could one attempt to find the best solution to this trajectory optimization problem in practice?

If there is a satellite in low Earth orbit, with a limited delta-v budget (but high enough to escape Earth) and limited delta-v-rate (thrust), how could one find an acceleration schedule and ...
3 votes
3 answers
1k views

Would orbital ring platforms affect the orbit of a planet?

If we built an orbiting platform of sufficient mass (let's say, made from harvested asteroids) that was anchored at both poles of the planet it surrounded, would such an addition to the planet's mass ...
1 vote
1 answer
280 views

What network does the Chandra X-ray Observatory satellite use to communicate with Earth while staying in its orbit?

From a NASA fun facts website How do satellites communicate?: How do satellites communicate? Satellites communicate by using radio waves to send signals to the antennas on the Earth. The antennas ...
1 vote
2 answers
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Chemical Problems When Encountering Thin Atmospheric Worlds

Bodies such as Enceladus, Mercury, and Triton, etc... have thin (and often temporary) atmospheres. When probes or landers encounter the chemicals in such atmospheres in low orbits/landings, they may ...
16 votes
2 answers
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Amateur satellite launch

Has there ever been a successful satellite launch done by amateurs? I mean both building the satellite and a rocket to carry it.
3 votes
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Satellite Surface Temperature in Orbit

I am trying to calculate the satellite surface temperature in Orbit for Thermal Tests of our satellite. Referring "Space Vehicle Design, D.Griffin, Ch.9, the equations of heat transfer on the ...
2 votes
1 answer
288 views

In MATLAB, Computing a new TLE/orbit following a delta-v impulse?

I have already worked on this project for a week, and I still can not solve this problem by myself. How can I update data for the SGP4 OrbitPropagator in Matlab's ...
2 votes
1 answer
225 views

Why Euclid's orbit is not like Gaia but like JWST?

Euclid, Gaia and JWST are all orbiting Lagrange Point L2. Why is Euclid's orbit similar to JWST but not Gaia's, why is Gaia's orbit different than Euclid and JWST ? Orbits are shown here for example:
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1 answer
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Would reaching an elliptical orbit with the same mean altitude as that of a circular orbit require the same amount of fuel?

Would a rocket that wanted to reach an elliptical orbit with a perigee of 100 miles (160 km) and an apogee of 300 miles (480 km) burn the same amount of fuel as a rocket that wanted to attain a ...
13 votes
3 answers
3k views

Does NASA have spacecraft that are specifically made for orbiting around the Sun?

Does NASA have projects with spacecraft which are specifically made for orbiting somewhere around the Sun? If yes, what can they be used for?
2 votes
1 answer
195 views

How do I calculate the maximum northern and southern latitude a LEO satellite can image?

How do I calculate the maximum northern and southern latitude a LEO satellite can image? What parameters would I need?
11 votes
3 answers
10k views

Who/What is the international authority to assign/refuse orbit to a satellite/space-craft?

This book writes to say In 1981 the USSR requested and was allocated seven satellite slots in 24-hr orbit for Earth observations, calling the system Prognoz Whom was the request made to? Who ...
5 votes
1 answer
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Would a sniper bullet fired on Ceres reach orbital or even escape velocity?

What would happen if you fired a sniper bullet horizontally from the top of Ahuna Mons, the highest mountain of Ceres? Once I read somewhere that if you fired a bullet on the Moon in the correct angle,...
1 vote
1 answer
174 views

Circularization of an orbit on gmat

I'm using Gmat to turn to zero the eccentricity of an orbit around Mars with an electric thruster. I modeled the initial orbit, introduced the engine, the tank and the solar arrays and created the ...
0 votes
2 answers
393 views

Orbit prediction for satellites using the Kepler model

I would like to know how to model the motion of satellites in orbit using Keplerian, i.e. develop a simulation model that tracks paths of satellites using Keplerian orbits in Python?
10 votes
2 answers
1k views

What's the motion of two connected satellites orbiting the Earth after their separation?

Let's consider the following problem (it's a job interview question): two satellites are orbiting the Earth in a circular orbit; they are rigidly linked by a tether which is always pointing in the ...
3 votes
2 answers
2k 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 ...
9 votes
4 answers
2k views

“Parabolic”, suborbital and ballistic trajectories all follow elliptic paths. Is there a generic term for these trajectories?

There are three types of trajectories which produce microgravity but intersect with the surface of the earth: Reduced Gravity Flights in airplanes. These are sometimes called “parabolic” but are ...
3 votes
1 answer
71 views

Finding or calculating orbital velocities of celestial bodies at periapsis/apoapsis?

I'm writing a solar system simulation that uses n-body physics. To plug in the celestial bodies in our solar system, I'm copying orbital values from wikipedia. For one example, the wikipedia page for ...
21 votes
4 answers
6k views

Does the Moon have any captured objects orbiting it?

Does our moon have any captured objects orbiting it that have been discovered, such as asteroids or other debris? If it doesn't, is it possible that it could capture them in the future, given the ...
2 votes
1 answer
462 views

Calculate position of planet on fictitious orbit each day

I'm a software developer but my degree with in mathematics. I'm trying to develop a game/simulation of a fictitious randomly generated solar system, and trying to work out how to model and calculate ...
10 votes
2 answers
5k views

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?
0 votes
1 answer
851 views

What is a Mars 5-sol orbit? [closed]

I need to calculate the delta-v for descent from 5-sol orbit to the surface of Mars and then ascent back to 5-sol orbit from the surface of Mars. What is a "5-sol orbit?"
1 vote
1 answer
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How do "halo orbits" save on propellent (delta-v)?

I am trying to understand what advantage the satellite's 'Halo Orbit' has compared to LEO or Geostationary orbits. "Lagrange points have proven to be very useful indeed since a spacecraft can be ...
7 votes
1 answer
10k views

How long can the SpaceX Starlink satellites survive before they deorbit?

Like most Low Earth Orbits (LEOs), the Starlink satellites will eventually have their orbits decay and burn up in the Earth's atmosphere. How long, on average, will this take? I am assuming that there ...
5 votes
1 answer
616 views

Where do I find ECEF coordinates of a satellite?

I am taking a university course named 'satellite navigation' as a part of my master degree in aerospace engineering. For the exam we are required to elaborate the coordinates of a LEO satellite (it ...
7 votes
2 answers
2k views

Re-entry Dynamics

I've been reading around a lot and I haven't been able to find any clear explanations. Maybe I'm a bit confused or maybe I am just looking in the wrong places. My question is, what are some basic ...
5 votes
2 answers
264 views

Reference to understand the notation of orbital charts

To address various orbital evolutions of spacecrafts, some particular orbital charts are taken into account. For example, the following is used to depict how a chaser reaches a target: The only thing ...
4 votes
3 answers
535 views

A black cube 1 mile per side appears in geosynchronous orbit around the earth. Who would spot it and how would they do it? How easy would it be?

This is not intended to be a math question, so much as an understanding of how the current technology and techniques would view this problem.
6 votes
1 answer
508 views

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 ...
3 votes
0 answers
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How much of a rocket energy is needed to overcome aerodynamic drag?

this question How much of a rocket's energy is used to achieve altitude vs horizontal velocity? addresses the energy split of kinetic vs. potential energy to get to space - and to stay there. We ...

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