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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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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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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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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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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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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i understandable, the tec do a thing is different, [closed]

what to know want would if the mass of mar was increased to the mass of earth. would change its orbit would it affect our relation to the sun or it moves out or would come in closer, the gravity pulls ...
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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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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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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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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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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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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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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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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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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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Poincaré map of orbital trajectories

A Poincaré map, by definition, is supposed to be a reduction of a phase diagram on a codimensional plane cutting normal to the original trajectory. In this form, one should plot points from the phase ...
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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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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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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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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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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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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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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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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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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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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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Transfer between circular orbits in up to 5 maneuvers

There are 2 circular orbits with different inclination and RAAN. I have to transfer from a specific point (true anomaly given) of one orbit to a given point of another in 1 month. The period of the ...
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How to implement SGP4 C++, satellite propagator?

I would like to ask about how to implement the SGP4 code in C++ by Vallado. How can I implement the libraries that are available in https://celestrak.com/software/vallado-sw.php. I think that are the ...
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Explanation of single-burn trajectories from Lunar surface to Earth surface

I learned of the fine book Soviet Robots in the Solar System from this excellent answer. One chapter in it describes how the Soviets had extreme mass limitations on their lunar sample return vehicle ...
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How to use “patch points” to make a continuous halo orbit?

update: I've found "patch points" mentioned throughout the following papers; it is likely that an answer can be found from these sources. Targeting Cislunar Near Rectilinear Halo Orbits for Human ...
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Is the Gateway's halo orbit bound to Earth? Would the Gateway remain in Earth orbit of the Moon disappeared?

Discussion below this answer involves my feeling that calling halo orbits in very asymmetric systems (e.g. Sun-Earth or Earth-Moon) as orbits around the primary, in 1:1 resonance with the secondary. ...
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Would a standard gravity turn still be the most optimal path to orbit if Earth did not have an atmosphere?

If Earth had no atmosphere, then would a standard gravity turn still be the most optimal path to orbit? Why or why not?
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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 ...
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What orbital mechanics toolkits available today are suitable for a real-time simulator?

I'm a software engineer and I've always loved Orbiter (also here). However I feel that it's growing a bit antiquated, and it would be nice to have a more modern, open source, or otherwise hackable ...
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How would off-apsis burn effect the angle and position of new apoapsis

Let's say you have an elliptical orbit, if you burn prograde at the periapsis, you extend the apoapsis by some factor(according to vis-viva equation). But if you burn prograde on somewhere during the ...
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On the dynamics of two connected objects located at different circular orbits

I'm just thinking about the qualitative and quantitative implications of a hypothetical orbital problem, but what I ended up does not make sense as it should. In particular, assume that two objects ...
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Where did the Herschel Space Telescope go in 2013?

The Herschel space telescope wins as largest optical telescope mirror in space when "optical" includes far infrared (~55 µm). The Wikipedia article Herschel Space Observatory lists the orbit as ...
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What are the orbital-mechanical advantages of a long (100+ second) sub-orbital coast phase?

This answer to Trajectory to get into orbit says: In most real launches to low Earth orbit, the burn continues from liftoff until orbital insertion, without a coasting phase. Some (like Antares) do ...
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Can we calculate elliptical properties in a spherical coordinate system?

Can we calculate the elliptical properties like the semi-major axis and eccentricity using the state vectors (position and velocity) in the spherical coordinate system? http://www.braeunig.us/space/...
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Can someone help Scott Manley explain this Snoopy-capturing maneuver?

In his recent video Apollo 10's Lunar Module Snoopy Is Lost In Space - Could We Bring it Home? Scott Manley uses some fancy supplemental techniques in KSP to simulate and explain a possible mission to ...
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Design of return trajectory from lunar polar orbit to Earth's atmosphere

Given a flight path angle, altitude and velocity at re-entry into the Earth's atmosphere, how do I go about designing the return trajectory from a polar orbit at 17km altitude about the lunar surface ...
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Using Differential Equations to model path of satelite around earth

I am new to GMAT and am hoping to use it to model the path of a Low Earth Orbit satellite around Earth. I am thinking of plotting the path on a plane and using polar coordinates to model the path ...
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How much Delta-V is needed for Orbital Maintenance?

My question is aimed at understanding the how much Delta-V is needed for orbital maintenance for different orbits. Obviously, there still is some residual air resistance that decreases as the orbital ...
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How do I calculate re-entry velocity when decaying from a circular orbit?

I am trying to find the velocity of an object during re-entry so that I can calculate the peak heat flux but I'm a bit stuck. I know how to find the velocity of the original, circular orbit (300km) ...
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How do I calculate the change in the argument of periapsis after a plane change maneuver?

Let's say I have a spacecraft in an initial geocentric orbit with the following parameters: a = 7,960,000 m, e = 0.010, $\Omega$ = 180$^{\circ}$, i = 98$^{\circ}$, $\omega$ = 90$^{\circ}$, $\theta_0$ =...
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Apollo 15 State Vector recreation

I am trying to get the state vectors for Apollo 15 before, during, and after critical manoevers [sp]. IE TLI, LOI1, LOI2, lunar launch, preocking, postdocking, and TEI. I am a totally newbie at all ...
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Using the distance components to calculate minimal dV randezvouz trajectory

The are objects on 100 circular orbits, 1 object on each orbit. One orbit is said to be initial (I) and others are final (F) . ...