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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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Is Dawn's upcoming low periapsis orbit for XMO7 “resonant”?

The Spaceflight Insider article Dawn will enter lowest ever orbit around Ceres says: In his Dawn Journal blog, mission director and chief engineer Marc Rayman discussed the challenges of bringing ...
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What is hyperbolic eccentric anomaly F?

I have no idea what this is and have been searching on the net but all I get is eccentric anomaly. The equation that relates hyperbolic eccentric anomaly F to its true anomaly $\theta$ is exactly the ...
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What sort of orbital elements are used to describe halo orbits?

For standard orbits we can use Keplerian elements, TLE, or other similar. These don't make much sense for Halo orbits, which are not around a central body, but around a Lagrangian point, and follow an ...
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How does the delta v for leaving Earth orbit change in different directions from the Earth?

Inspired by this answer on How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits?, which states Move to the edge of the Hill sphere, sit at Earth-...
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Deploying multiple satellites from one second stage

I’m just watching the Iridium-6/GRACE-FO launch from SpaceX. Before the launch they showed a video of the Iridium satellite network and in this mission they deployed 5 additional satellites into LEO. ...
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How to intuitively explain that tri-elliptic transfers are not better than bi-elliptic transfers?

The question How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits? includes the graphic below, which illustrates that when transferring between ...
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1answer
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Would the barycenter in a binary star system be ideal for a space habitat?

I was reading about binary star systems and saw a bunch of diagrams, mainly the following: Would there be benefits to creating a space station in the center of two binary rotating bodies? Would it be ...
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192 views

Can orbital maneuvers be performed by a solar sail to correct eccentricity?

This unique model would spend very little time in Earth's shadow and eccentricity correction is performed on every pass. Can the angle of the hard flat solar sail or one big solar vane maintain an ...
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Can modified solar sail use Earth's atmosphere to correct an eccentric orbit?

A solar sail power satellite used create thrust as a while in orbit around Earth will gain eccentricity because it can only propel from on side of the Earth. When the orbit will become eccentric ...
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MATLAB optimization script for Low - Thrust trajectory

I'm trying to write a script for a 'shape based' trajectory, based on the exponential sinusoid shape, for an Earth - Mars transfer. Essentially, I know where I want to start, and I know where I want ...
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102 views

What are the symbol definitions in the equations for finding orbital elements?

I've been looking at the answer to this question on how to convert position and velocity to orbital elements, but some of the symbols are not defined and there are no reference links for those symbols....
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How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits?

Studying again orbital maneuvers, I found the following plotting the cost of a Hohmman transfer between coplanar circular orbits (black line), in terms of $\Delta V$ against the orbit ratio $r_f/r_i$. ...
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How can I look for the best date of launch for gravity assist?

I am new to astrodynamics, and I am trying to learn about gravity assists, but I don't understand how I can easily decide a launch date and arrival late for the planet in which I calculate the gravity ...
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Is it possible for an asteroid to be captured by earth in such a way that it has minimal relative velocity?

Is it possible for a metal (or dirt/ice) asteroid of 1km average diameter to enter the Earth-Moon system in such a way that the asteroid behaves as if it were dropped from a height instead of as a ...
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What orbit is this?

Can this orbit exist around the Earth and the Moon if the weight and speed of the satellite is ideal? I have added a picture below with the orbit drawn.
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What artificial satellite has the farthest orbit around the Earth?

What is the furthest Earth orbiting satellite? What is its speed and purpose?
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Can a satellite work like a radiometer?

Like a Crookes Radiometer, could a satellite have a stiff vain to maneuver? With a white side to let light pass and the black side capture light radiation be enough provide radiation pressure to keep ...
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1answer
522 views

Does the size of a satellite have an effect on orbit?

I understand that lighter satellites orbits decay faster. There is 2 satellites that weigh the same but 1 is huge and the other tiny in comparison. Would the size of the satellite make a difference on ...
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Help understanding negative apogee coinciding with exact center of Earth (Mars InSight launch)

Watching the NASA JPL video NASA Launches InSight to Mars (Part 2) after MECO-2, the orbital parameters shown in the video don't make sense to me; specifically the apogee altitude. At this point in ...
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Can someone give me a 'trajectory optimisation for dummies' answer?

So, I am currently doing a project on trajectory optimisation. I get the principle of it, minimise fuel cost for a journey, or try to maximise the spacecraft weight at target destination, and that ...
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1answer
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When should a rocket be launched to reach a Near Earth Asteroid like 2001 US16?

Earth takes 365.25 days to complete its orbit around the Sun. Earth also travels at 67000 mph. Asteroid 2001 US16 (also known as 89136) takes 577 earth days to complete it's orbit around the Sun. To ...
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2answers
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Orbits that allows observation of a polar region

If a mission is only interested in a single polar region of a planet, what kind of orbit would be most fitted for the satellite. The first things that comes to mind is a polar orbit, but then it ...
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2answers
478 views

Satellite altitude as a function of time?

In order to obtain a more accurate radiation estimate in this question, I am trying to approximate and/or determine the altitude of a satellite as a function of time. The satellite has an apogee of ...
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How does the delta V to reach and orbit L4 and L5 compare to entering orbit around the Moon?

The L4 and L5 Lagrange points, 60 degrees in front of and behind the Moon in its orbit around Earth, orbit at the same speed as the Moon. But when a spacecraft flies to the Moon, the gravity of the ...
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1answer
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Propagation of pressure waves in Low Earth orbit

So in a Wikipedia article about space debris i read that---- At higher altitudes, where air drag is less significant, orbital decay takes longer. Slight atmospheric drag, lunar perturbations, ...
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2answers
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How much G force is applied when correcting an orbit around Earth?

How much g force is applied to a satellite to correct a decaying orbit if done each orbit? How long does it take to correct an orbit on the average? I understand there are variables as in which orbit ...
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Quick and dirty way to estimate flight times for constant acceleration rockets

Thought experiment: Suppose we build a spacecraft with a low thrust electric propulsion and have a flight plan that involves constant acceleration on the first half of the journey, breaking on the ...
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534 views

Mars transfer window frequency

According to this website I drew up a timeline of Mars transfer windows and the time you'd need to stay on Mars before the next return window: Blue to red arrows are Earth to mars transitions, red ...
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1answer
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What does the phrase “topological point of view” mean when applied to two-body orbits in this context?

A recent question includes the passage: From a topological point of view, it seems likely that any rigid body would have to admit at least one stable low orbit, regardless of mass concentrations. I ...
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What is the feasibility of a rocket hobbyist achieving a LEO orbit with a microsat?

Along with being a rocket hobbyist, I'm also an Amateur Radio Operator. I would like to determine the possibility of placing a "microsat" a miniature packet radio satellite, into a low earth orbit.
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Can bad satellites be pulled out of orbit with an Orbital Mass Accelerator? [closed]

Could an Orbital Mass Accelerator OMA be used to knock other satellites out of orbit? Leaping from satellite to satellite using a magnetic field to accelerate some useless satellites and decelerate ...
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0answers
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Is it possible to dock with a ship that is on a Galileo-like trajectory?

Reading about missions that have made or will make heavy use of gravity assist (Galileo, Cassini, MESSENGER, BepiColombo...) made me wonder about what if a heavy unmanned ship (BFS?), with all the ...
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1answer
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First interplanetary launch from California! How far from Earth will InSight be when it separates from the Centaur 2nd stage?

The Phys.org article Bound for Mars—countdown to first interplanetary launch from California says: In the early morning hours of May 5, millions of Californians will have an opportunity to witness ...
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Teleporting an object into geosynchronous orbit

Assuming that a method was found to teleport objects, and at huge range, if an object was teleported from the surface to a location at the correct height (wikipedia says about 42,164 km from earth's ...
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1answer
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Why is Nodal precession affected by the rotational period of the planet?

The $J_2$ term in Nodal Precession equation has the rotational period of the planet. I understand that the oblateness of the sphere with an equatorial bulge induces a torque on the orbit of a ...
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3answers
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If you throw a baseball from the space station, will it return to you in 90 minutes?

Something I've learned playing Kerbal Space Program is that if you make a change in your orbit with a single, short maneuver, your new orbit will intersect your old one at the point where you made the ...
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1answer
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Why was TESS' launch window open for only 40 seconds per day?

The BBC news podcast Science in Action episode New Planet Hunting Mission covers the upcoming TESS mission between 01:00 and 07:15 with Sara Seager, TESS deputy ...
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Would space ship/station rotation for artificial gravity cause the “axis” to also rotate?

Would space ship/station rotation for artificial gravity cause the "axis" to also rotate similar to that of a helicopter with out a tail rotor? Additionally would a second rotating section going in ...
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To what extent is the orbital Time Period of ISS affected by soyuz thrusters?

Numerically, to what extent is the orbital time period of ISS affected during the time when it boosts back higher to gain the lost altitude, using Soyuz thrusters/engines?
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Why does Earth not appear to be at the focus of TESS' elliptical orbit in this video?

An excellent review of all of the considerations and work that has gone into designing TESS' orbit can be read in the ArXiv preprint A High Earth, Lunar Resonant Orbit for Lower Cost Space Science ...
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How to calculate mass of fuel for Venus Orbiter

I'm working on a hypothetical constellation of orbiters at Venus for a school project, and I am currently trying to figure out how much fuel I need in the transfer stage. I have already calculated ...
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1answer
383 views

C3 calculation in interplanetary missions

I'm starting to study Astrodynamics and I'm trying to make a Porkchop plot for a Mars mission to compare the results with actual porkchop plots which I found on the internet, so I know if my ...
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2answers
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TESS orbit and moon resonance

On April 17 the Space X will launch TESS satellite. Satellite description: The Transiting Exoplanet Survey Satellite (TESS) is a planned telescope for NASA'S explorer progra. designed to search ...
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Were the Apollo lunar ALSEP transmitter signals ever analyzed or used after the experiments were shut down?

This answer to the question Why were the “perfectly functioning” seismometers placed by Apollo 12, 14, 15 and 16 astronauts all shut off in 1977? links to a NASA News Release No: 77-47 dated September ...
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Can Radiators be used as thrusters? [duplicate]

So i was recently recently reading about this phenomenon called the Yarkovsky effect: The Yarkovsky effect is a force acting on a rotating body in space caused by the anisotropic emission of ...
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3answers
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Why doesn't the ISS use ion engines to maintain altitude?

So the ISS uses small thrusters on the Soyuz (usually) to perform occasional reboost burns to raise its orbit. This goes through, from what I can tell, around 3,500 kilos of fuel per year. Would it ...
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What size payloads could we feasibly launch from the moon with a mass driver?

I've been wondering how large a payload could be launched & if it's viable to launch those payloads directly to the earth for splashdown & collection. Obviously the payload would need to be ...
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How massive can a planet become before it is impossible to escape from using chemical rocket propulsion? [duplicate]

Assuming a vaguely Earth like world but with higher gravity, at what point is it no longer possible to launch a human being from the surface into orbit? Or anything into orbit?
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548 views

How to calculate a transfer orbit

I'm starting to study by myself orbital mechanics, but I don't understand well how can be calculated the transfer orbit. If I have for example a route Earth-Jupiter, how can I calculate it? I've read ...
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How to calculate the change in inclination due to perturbations?

I would like to know the how much the inclination for a generic elliptical orbit changes over an unspecified period. The variation of inclination fluctuates as per a thread listed at the bottom. I'd ...