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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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Could solar sails be used in station keeping?

Could solar sails work in place of solar vanes for passive stabilization in station keeping a satellite fixed in the Lagrange 2 point on a parallel orbit with the Moon? Related: What is the ...
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What is the darkest orbit around Earth?

What orbits around Earth has the least and most sun light exposure? I wondered: When taking pictures either of Earth or otherwise with various telescopes in orbit, does it help to be in Earth's ...
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General expression describing the trajectory of a bullet in orbit - fired in an arbitrary direction (version 2)

This replaces a previous similar question that I could have formulated better. I'm in orbit and I fire a bullet in an arbitrary direction. I could shoot (1) Along the direction of the orbit ...
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What do terms of NASA's event list of SOHO mission mean?

In the SOHO mission Event List SOHO Event List there are a few terms I am hoping to understand. I assume MCC1 X-1 Burn refers to a mid-course correction. What does the number 1 and X-1 mean? For ...
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Could a ball of water stay in orbit?

Could a water bubble (spherical occlusion of water in air or vacuum) similar to the one in the picture below remain in Earth orbit without evaporating, dispersing, or disintegrating? Assume the orbit ...
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Accuracy of ECI (J2000) to ECEF (WGS84) for a LEO satellite only accounting for Earth Rotation

I am working on developing a simple J2 orbit propagator for a project I am working on and am at the stages of converting from ECI to ECEF. Looking at this reference document in section 2.4, what ...
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109 views

Bombing the Moon: how much debris would there be in stable orbit?

If someone had actually nuked the Moon (e.g. here or Bombing Moon and Mars: What would it look like? ), what's the probability of some debris reaching a stable orbit around the Moon? This would not ...
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Software for orbital sketches

I am looking for recommendations on software that can create orbit sketches such as the image below. Adding an informative sketch to an article can help readers better understand the idea. I am ...
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How do I calculate the Characteristic Energy for a rocket to Near Rectilinear Halo Orbit where the Deep Space Gateway is gonna orbit moon?

How do I calculate the Characteristic Energy for a rocket to Near Rectilinear Halo Orbit (NRHO) where the LOP-G or the Deep Space Gateway is going to be orbiting the moon? Or if someone already has a ...
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Would a self-winding watch work in space without gravity?

Could a watch that winds itself with a pendulum work in space with no gravity? Could a pendulum or the self winding part be modified to work off the movements of the wrist in a microgravity ...
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Calculations Apollo astronauts were trained to do by hand if loss of guidance computer and/or data & coms link to Earth?

This answer to the question is it possible to navigate space travel with no computer? currently contains the line Yes, as long as you don't care where you end up but I am not so sure this is true. ...
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Why might NASA need to “practice moving a spaceship in different orbits in deep space”?

The NASA.gov feature Q&A: NASA’s New Spaceship says Q: NASA’s really building a spaceship?! A: That’s right! NASA is working with its partners to design and develop a small spaceship ...
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Is there a flight simulator showing the gravity well of the Earth and Moon? [duplicate]

I tried the Kerbal Space program and could not get it working on my CPU. Is there a chart or program that is light weight that I can run simulations on?
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Why does ExoMars have more landing ellipse flexibility in 2020 than in 2018?

The BBC's ExoMars: Where to send Europe's robot rover? discusses the decision-making faced by the ExoMars Site Selection Working Group. The working group will spend Thursday and Friday discussing ...
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Ideal shape for a long, skinny reaction mass for LEO to cis-lunar and beyond? (a “space rail gun”)

@Ingolifs' answer got me procrastinating thinking further. What you're asking about is a mass driver space station in low earth orbit that a payload or ship launched from earth can dock with, and ...
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How is a satellite constellation launched?

If want 10 satellites chasing each other around the earth (evenly spaced) all one the same plane, these satellites would be evenly distributed around the globe after launch by slightly raise or lower ...
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Tesseral Part of the Geopotential

I am working on the design of a constellation for academic purposes. I try to describe a phenomenon that appears in the simulations by means of analytic expression and I can't really find a good ...
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Where is Lucy going? (asteroid mission)

On Halloween (31-Oct-2018) NASA Goddard announced that Lucy has a green light: NASA’s Mission to Jupiter’s Trojans Given the Green Light for Development All I have are these links which are now ...
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Why are there no LEO satellites in the earth's equatorial plane?

From my elementary school understanding of Satellite orbits, I know that GEO satellites are placed in equatorial plane, MEO satellites are placed in an smaller degree inclined plane while LEO ...
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What was the speed (avg, min, or max) of ARTEMIS-P1 spacecraft as it orbited L1 and L2

If not specifically ARTEMIS-P1, then what is the average speed (or mins and maxs) of a spacecraft orbiting EM L1 and L2 in halo and Lissajous orbits? Are there varied orbital periods for those points?...
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RIP Kepler, how shall we call your orbit? Does this cyclic flip-flop process have a name?

So long, and thanks for all the Fish Planets The captions in the NASA Ames Research Center video What Will Happen to NASA’s Kepler Spacecraft? read as follows: NASA’s Kepler space telescope found ...
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What's the difference between zenith and radial?

When it comes to orbital mechanics, are zenith and radial the same? Or to put it another way, are nadir and anti-radial the same?
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Geometry of full global coverage with 4 supersynchronous satellites, 3 or 16 control stations

in order to provide a truly global coverage of the Earth from space, including the polar regions, a minimum of just 4 satellites is required. Placed in precise 63.4 degree supersynchronous orbits, one ...
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Measuring the effect of Earth tides

In order to calculate the acceleration due to the geopotential, I've already implemented the EGM-2008 TideFree model, getting the coefficients from the link. Is the Earth tides effect already ...
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How to make satellite ground track on map?

I want to make satellite ground track using matlab. I already had a position of satellite(ECI) by solving Kepler equation. And I know convert ECI to ECEF using rotation determinant. Then I convert ...
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Could a satellite in LEO “pump” or change mass distribution to gain forward momentum?

Similar to pumping your feet on a child's swing can a satellite run up and down a pole to produce a forward momentum? Red dots is the satellite's position running up and down the pole on an ...
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What is the source of Scott Manley's plot of Messenger's end of mission perihermion loss?

In the video Why Does it take BepiColombo 7 Years To Get To Mercury? Scott Manley nicely explains some of the basic orbital mechanical aspects of the mission and compares it to the Messenger mission. ...
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The sorting of perturbational effects by the power

I have developed an orbital propagation tool, which considers the effects of Sun, Moon, Earth harmonics, SRP, drag, relativistic correction. First question Considering the LEO orbit, I would sort ...
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Spacecraft-fixed coordinate system

I am working with data from a polar-orbiting satellite (inclination 97 degrees) with limited attitude information. I am trying to define a coordinate system which is fixed with respect to the ...
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How would a Jupiter flyby have helped to get to the Sun? Why was it later ruled out?

The quote below surprised me. What were the orbital mechanical details of using a Jupiter flyby to get a probe from Earth so close to the Sun? Was a "U-turn" possible; single flyby of Jupiter into a ...
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Would adding a long pole to the International Space Station keep it from tumbling via gravity gradient stabilization?

What things can be done mechanically to make the ISS more stable in a dormant state without a crew? I have listed a couple of links that may work, but I am open for constructive criticism and new ...
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What will happen to Parker Solar Probe in the long term?

Will the probe be intentionally crashed anywhere? Or is keeping space decontaminated not an issue here since temperature and radiation will sterilize anything in that kind of orbit?
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Why is DSCOVR in a Lissajous orbit instead of a halo orbit (to stay out of Sun exclusion zone)?

Halo orbits are a sub-class of Lissajous orbits. See this answer for (much) more on that. DSCOVR's orbit will put it in it's Sun Exclusion Zone in about 2020 where the communications line of sight ...
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What is the difference between halo orbits and Lissajous orbits?

The Wikipedia articles for halo orbit and Lissajous orbit leave me wondering how these two orbits are different from an orbital mechanical point of view. Could they be discussed together here, so I ...
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Difference between approach maneuvers to the insertion points of halo and Lissajous orbit?

I have read that spacecraft use two mid-course corrections to approach the Lagrange point, then do a final orbital insertion maneuver to enter into a halo orbit. Are there any specifics about this ...
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Is it possible for amateurs to determine the orbit of satellites

Maybe some people urge this is a DIY site question but i thought here is the proper place to ask this question. Is it possible for amateurs like students with commercial and available equipment like ...
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Orbital propagation: atmospheric drag

I'm developing the numerical orbital propagator. I've already implemented the Newtonian gravity (Earth, Sun, Moon), Earth harmonics, SRP and relativistic effect. The software is compared with GMAT ...
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How accurate can a satellite's orbit be?

How precise can an artificial satellite be when it comes to following the exact orbit in relation to Earth or hitting the same point above Earth in orbit? Which orbit would be the most stable for this?...
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What is the speed of ISS relative to ground surface?

Is it 7660 m/s or (7660-460)m/s? If it is the former then the ISS orbits about the Earth at 8120 m/s. I think it should be (7660-460)m/s relative to ground based on this orbital period formula, $$T=...
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Why does in-flight mission abort often ends in ballistic high-$g$ reentry?

I am seeing a lot of references to the “ballistic reentry” mode of the crew return vehicle in relation to the abort during the powered ascent stage. In partiulat, the recent crewed Soyuz MS-10 abort ...
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Could the International Space Station be fitted with solar sails?

How much solar sail and vane surface area would be needed to replace the boosts needed to keep the ISS in orbit? Could this be done at a higher orbit minimizing atmospheric drag? What is the closest ...
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Is Hohmann transfer the most frequent transfer orbit?

I have to complete a project for a university exam. The task is to design an interplanetary trajectory from Earth to Saturn, and to compare it with a Hohmann transfer to the same planet. I also have ...
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Terraform via moving Ceres To Mars orbit, using ion drive

EDIT: Apparently the accepted physics has changed, and we now use the convection model for generating planetary magnetic field, not the dynamo model. Next thing you know people will be telling me ...
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How can I calculate the orbital elements from two position vectors and a time difference?

I have two position vectors for my satellite, and I know that the satellite reaches these two positions 15 minutes apart. I know I can find the inclination using linear algebra and my position ...
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Spherical solar radiation model (GMAT)

I'm using GMAT to analyze the orbits. There is a Spherical model for Solar Radiation Pressure. Which equation does GMAT use to calculate it? I've already searched in the documentation, however, there ...
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How to match orbital speeds of 2 or more satellites in different orbits?

Satellite ME is orbit around the Moon and Earth. Satellites E is around Earth. I understand the low orbit satellites orbit at higher speeds. Can Sat ME match the speed of any of Satellites E at any ...
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What is this perturbation effect called, and what would be an analytical expression for the resulting eccentricity oscillations?

In this answer I've generated some oscillations of eccentricity by being somewhat naughty and propagating a TLE for +/-250 days from epoch. I believe it's okay for the purposes of demonstrating gross ...
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Can objects be deorbited by a satellite using a magnetic field?

Can a magnetic field be made around a satellite for a split second to gain or loose momentum from another satellite or debris with a few passes with a near-miss trajectories on larger debris? Could a ...
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Differences between SGP8 and the standard SGP4? Is it ever used in practice?

The Wikipedia article Two Line Element Set says: The SGP4 model was later extended with corrections for deep space objects, creating SDP4, which used the same TLE input data. Over the years a ...
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How much delta-v would Hayabusa-2 need per day to remain 20 km sunward of Ryugu?

Hayabusa-2 is near the astroid Ryugu, and both are essentially in nearly-matching heliocentric orbits around the Sun. Hayabusa-2's "hangout" is about 20 km sunward of Ryugu. For the purposes of this ...