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. For the movements of celestial bodies, see [celestial-mechanics].

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4answers
6k views

How many petaflops does it take to land on the moon? What does Artemis need with an Aitken?

All of the top five answers to The Martian: Does it really take a supercomputer to calculate spaceflight maneuvers? are essentially "no, orbital mechanics isn't rocket science". Okay I have used some ...
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Were there any identified launch windows and gravity-assist trajectories that could put a probe on a “Grand Tour” trajectory around 1981?

For context, I am developing an alternate history that features a far more ambitious Voyager program than the one undertaken in real life. However, despite the increase in NASA funding provided in the ...
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1answer
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Will Kerbal Space Program 2 have Lagrange points, halo orbits, and other 3-body goodies? [closed]

At about 05:37 in Scott Manley video Kerbal Space Program 2 - What We Know About The Sequel So I’m cautiously optimistic and I really obviously want this to be ...
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1answer
99 views

Accuracy of ECEF to ECI, using just GAST

I am working on a Low to Medium fidelity orbit analysis tool. My key factor here is speed, I am analyzing constellations with 500 - 1000 satellites and want to be able to perform the analysis in under ...
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1answer
89 views

Can I exclude coriolis effects if I express a rocket launch in an inertial reference frame for a rotating earth?

I am wondering if I can exclude coriolis effects and centrifugal forces if I calculate my position relative to an inertial reference frame with as origin the launch site at the moment of lift off. ...
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Could another Earth sized planet safely orbit our Sun? [closed]

I'm writing a soft science novel and have bumped my head on hard science. I need to know if an earth sized planet could be placed in orbit in our system, without destroying it or Earth. Minimum time ...
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2answers
213 views

Do “partial” Hohmann transfers exist?

I'm doing some research for fiction writing, and I would like to have my plot points comply with known science whenever possible. Regarding orbital transfers, I know that the fastest way from orbit A ...
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0answers
77 views

Launch vehicle trajectory tool for ascent phase to orbit using PYTHON

Currently, I am developing a trajectory optimization tool for launch vehicle from lift-off to orbit using python for my project. Since I'm new to optimization problem, I am finding it hard to ...
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1answer
120 views

How does one calculate the argument of periapsis of an orbit after an arbitrary maneuver?

Given a satellite in an equatorial orbit, a specific prograde or retrograde burn is executed at an arbitrary point within the orbit, and I need to calculate the resulting orbital ellipse. The ...
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1answer
274 views

What is the optimal inclination change strategy?

Consider a transfer between two circular orbits of similar radius, the only difference being the inclination difference, $\alpha$. What's the minimal $\Delta v$ required to perform this transfer? ...
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1answer
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Is the amount of accurate information in a TLE equal to that of a single state vector?

My question is basically regarding whether there is orbital information "lost" when converting from a Two Line Element set (TLE) to a state vector. Given that the following are true: I have a TLE, ...
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1answer
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How will Chandrayaan-2 reach a polar orbit?

This Wikipedia article says the the Chandrayaan-2 orbiter will be in a polar orbit above the moon. The orbiter will perform its mission for one year in a circularized lunar polar orbit of 100 × 100 ...
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1answer
247 views

Did SpektrRG make a “u-turn”, and how does this ground track remain a steady 6° above the equator?

This tweet The second (crucial) engine firing of the Block DM-03 stage in today's #SpektrRG launch to come in an hour, when the spacecraft almost completes its first orbit around the Earth. Here is ...
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1answer
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Spacecrafts: NED frame to Orbit Frame or Body Frame Transformation

I calculate the geomagnetic field using IGRF model in Matlab. However, the output is in the NED coordinate frame and I want to tranform it into the Body frame. I've searched everywhere and I cannot ...
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1answer
149 views

How often does the ISS orbit over the same latitude and longtitude, at exactly the same time of day, as previously?

It appears that all spacecraft orbit within different parameters, dependant on altitude, and orientation to earths turn. The ISS synchronizes its orbit every 6 days(same latitude,same time of day) but ...
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3answers
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How is foot-pounds of energy defined?

Tom Lodgson's classic textbook Orbital Mechanics: Theory and Applications frequently measures energy in foot-pounds, which I'd always thought to measure torque. The book doesn't define it. Is it the ...
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2answers
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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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0answers
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Orbital period from TLE data [duplicate]

Is there a way to calculate the orbital period from the Two Line Element (TLE) data?
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7answers
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Why did Saturn V not head straight to the moon?

This may seem a naive question, but as I understand it one of the reasons for the enormous energy expended by rockets is the extremely high speed (around 28,000kph) you need to achieve a stable orbit ...
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2answers
94 views

What is the process to verify the orbit of a satellite in a list of artificial earth satellites?

From the answers to What is the name of the 'register' that keeps track of all the satellites? we can see that there are more than three 'registers' of artificial satellites - starting with: The ...
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2answers
113 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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0answers
63 views

How to plot conic from Lambert solver

I am trying to solve for an optimal multi-gravity assist trajectory from Earth to Saturn using Matlab. I have already solved for the departure and arrival velocities from and to each planet using a ...
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2answers
176 views

What orbit would a space station need to stay in orbit for $N$ years?

(posted before on physics stackexchange but was told to come here) I'm reading this book which has a post-apocalyptic setting. At one point you look at the earth from the view of a 1000-year-old ...
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1answer
411 views

Calculate Argument of periapsis of orbit given focus and two points on ellipse

Given that I know the coordinates of one focus (the central body) and two points on the orbit (two vectors) how do I calculate the argument of periapsis? And Longitude of the ascending node as well? ...
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2answers
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Gravity assist from Mercury

The Oberth effect states most energy can be gained when you have highest velocity in orbit. The interplanetary missions, generally involve ion propulsion along with gravity assist from planets such as ...
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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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1answer
151 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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1answer
97 views

Why does TDRS 1's inclination evolve so much differently than that of all the others starting in 1995?

The plot below is from the question Why do the geosynchronous TDRS satellites have this distribution of inclinations?, and the explanation says Inclination and mean motion (rev/day) for TDRS ...
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How can I “debounce” these TDRS satellite inclinations? (reconstruct the zero-crossings)

The plot below is from the question Why do the geosynchronous TDRS satellites have this distribution of inclinations?, and the explanation says Inclination and mean motion (rev/day) for TDRS ...
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1answer
109 views

Where can I find simple-ish math(s) about Moon launches from Earth and fuel consumption etc.?

I'm intrigued by the idea of launching from the top of a space elevator perched on the top of a Ecuadorian mountain, launching Eastwards to take advantage of Earth's spin. I'd like to just understand ...
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1answer
930 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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1answer
174 views

Why put X-ray telescope Spektr-RG/eROSITA all the way out at Sun-Earth L2?

Per Wikipedia's Spektr-RG; Mission profile and orbit: Mission profile and orbit The spacecraft will enter an orbit around the Sun, at the L2 Lagrangian point, about 1.5 million kilometers away ...
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1answer
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What is the latest plan to ameliorate the largest drifts of orbital space debris?

Given decades of orbital space launches around the world for whatever reason, there are now massive constellations of many hundreds of thousands of pieces of cast-off hardware and fragments of ...
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1answer
138 views

LVLH to ECI Conversion

I'd like to transform LVLH coordinates to ECI coordinates. I've been looking at academic papers and other answers on here and other websites and have only seen the transformation in the other ...
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2answers
132 views

Free Fall to Earth from Solar North Pole?

Inspired by this answer At the right time of year you can position yourself at say 100 AU from the Sun in the plane of the Earth's orbit and just let go. With no tangential velocity, the Sun's ...
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1answer
87 views

Is aerobraking used for orbit insertion for each planet with an atmosphere?

Probes designed to orbit planets can use aerobraking to help orbit insertion (as it has already been done for Mars Reconnaissance Orbiter or Mars Global Surveyor). Such techniques could be used for ...
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3answers
174 views

Could a spacecraft fly in a direct line from the outer solar system to Earth?

The Johns Hopkins University Applied Physics Laboratory website depicts the New Horizons flight path as almost a straight line after the Jupiter flyby. Could a spacecraft travel from the outer solar ...
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1answer
97 views

Does the Delta v to leave the entire solar system depend on its angle to the ecliptic?

Does the delta-v requirement change depending on the angle a craft is leaving the ecliptic? If a craft were to be leaving only a few degrees above the ecliptic, would it take less delta-v than if a ...
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1answer
131 views

Does Lightsail-2 take significant advantage of the Oberth effect?

The cubesat Lightsail-2 has been deployed and has communicated with ground stations. See The Planetary Society's LightSail 2 Healthy as Mission Team Continues Spacecraft Checkouts In the near future,...
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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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84 views

RTN to ECI conversion of acceleration

The problem I am working is one of orbit determination. I am adding some virtual accelerations to a an Earth centered LEO satellite in the RTN frame, which is attached to the satellites' center of ...
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0answers
47 views

Mean to Osculating conversion for non-J2 averaged elements

What is the appropriate technique to convert mean elements (true anomaly averaged) into osculating elements when the model has J2, SRP, drag and additional forces modeled. Brouwer's transformation is ...
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1answer
82 views

Are the propesed Launch UK facilities in the wrong places?

I live in the UK (Cornwall specifically). I was recently told that the UK Space Agency (UKSA) was doing a project to launch rockets in Newquay. I did some more research and found that, according to ...
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5answers
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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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0answers
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Converting data from NASA's Trajectory Browser into state vectors

I've found this super awesome tool, provided by NASA, called Trajectory Browser. I would like to simulate some of the trajectories listed there but can't quite figure out how to convert the trajectory ...
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1answer
113 views

Space Shuttle Moon Mission? [duplicate]

Theoretically speaking, could the shuttle have performed TLI, LOI, and TEI burns given extra OMS fuel? approximately how much fuel and payload bay space/mass would this take up and might there ...
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2answers
188 views

Are Lagrangian points associated only with the smaller body?

Diagrams of Lagrangian points I've seen always show the points near the smaller object, following its orbit about the larger one. For instance: from Wikipedia. But in fact the smaller object ...
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0answers
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How can I calculate the azimuth from an earth station to a satellite

I have computed the ecef coordinates of both the user location on the ground, the satellite's ecef coordinates, as well as other inputs such as altitude, lat, long of both satellite and earth station....
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0answers
53 views

How accurate can a point in space be determined by the likes of the ICRF?

How accurately could a 3D point in open space (i.e. not on an object), say at an elevation of 30,000m above sea level, be located or modelled using the likes of the International Celestial Reference ...
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1answer
291 views

Converting Keplerian coordinates into Latitude and Longitude

Introduction My goal is follow up the title of this question and obtain the Earth coordinates (latitude, longitude) from the keplerian coords ...

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