Questions tagged [lagrangian-points]

Lagrangian points (also Lagrange points, L-points, or libration points) are the five positions (L1 - L5) surrounding two celestial bodies where gravitational pull of the two large mass bodies provides the centripetal force required to orbit them. Such points are usually nominally unstable but somewhat periodic around celestial systems with stable orbits.

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Are the Earth's 10 Lagrange points stable and large enough to park multiple satelites/space vessels

I know that we already have satellites in position at our Lagrange points, but what if we want to use them to park spacecraft sections for assembly reasons, or possibly even a meteorite for mining. ...
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Do objects at the $L_4$ and $L_5$ points conserve angular momentum?

A planet in an elliptical orbit around a star conserves angular momentum. (This is tantamount to saying that it sweeps out equal areas of the ellipse in equal times). If conditions are such that ...
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Does it even make sense to talk about Mercury's triangular libration points (L4, L5)?

The recent question How much radiation shielding would be required for a habitat at Mercury–Sun L5? got me thinking. There are a large number of disadvantages and challenges to building or putting a ...
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Minimum Delta V to a staging area in cislunar space for a vertical space gun

Space guns have a lot of confounding factors for getting to LEO. The projectile must be a rocket capable of large delta v in order to circularize the orbit. Then, giving more sideways velocity ...
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Do Lagrangian points apply to eccentric orbits or binary systems?

The assumptions about the Lagrangian points being stable (...in the traditional meaning of the word: not moving around; they are unstable in the mathematical sense, except for arguably L4, L5) that I'...
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Why would Hollywood's Planet X (at earth's L3) be unstable?

This NASA website states "NASA is unlikely to find any use for the L3 point since it remains hidden behind the Sun at all times. The idea of a hidden "Planet-X" at the L3 point has been a popular ...
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Any satellites in Earth-Sun L3 point?

Do we (the humanity) have any satellites in the Sun-Earth $L_3$ point? If not, then what are the plans to put some ships into this point?
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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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Are L1 to L2 and back “cheap” transfers/cyclers possible?

This paper studies transfers from halo orbit to halo orbit in the Jovian system. I wonder if there are any locally stable orbits connecting Earth-Moon L1 and L2 points. EDIT: One should also consider ...
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What is the period of halo/Lissajous orbits?

Does the orbital period of halo/Lissajous orbits around L1/2 points increase, decrease or stay the same when increasing the (average) orbital radius? A function period(radius,m1,m2) would be cool, ...
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How can Sun-Jupiter Lagrangian points be used by flyby probes?

Sun-Jupiter L1 is 1/3 of an AU from Jupiter. Could it be used to slow down or redirect a spacecraft approaching Jupiter? And the same for Sun-Jupiter L4 and L5 for a spacecraft on the way to e.g. ...
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Does the Earth have any Trojan asteroids?

Are there any known Trojan objects residing in the Sun-Earth L4 (SEL4) and L5 (SEL5) Lagrange points, also named "Greek" and "Trojan" groups, respectively?
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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 far would the Mars L1 Lagrangian Point be from Mars?

I am a sci-fi writer, and I've heard about the concept of putting some type of magnetic deflector near the Sun-Mars L1 point to deflect charged particles from the Sun to reduce radiation effects on ...
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'Orbiting' Earth-Moon $L_1$

I'm a Sci-Fi author, trying to keep the physics real in my books. I am in the process of moving a space station to the Earth-Moon $L_1$. I've read that a vessel can't just sit at that point, but has ...
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How can I calculate the Characteristic Energy to Sun-Earth L1?

Alternatively, does anyone know it? I'm asking in regards to the upcoming DSCOVR (Deep Space Climate Observatory) mission scheduled to launch aboard a Falcon 9 v1.1 rocket in January 2015. DSCOVR is ...
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Nature of Hayabusa-2's “Home Position” relative to Ryugu? Is it Ruygu's L1?

This tweet "from Hayabusa-2" via JAXA shows the diagram below, which seems to suggest that the Hayabusa-2 spacecraft tends to remain between the asteroid Ryugu and the Sun. Does Hayabusa-2 have to ...
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Do Lagrange-like regions temporarily appear around planets with multiple moons?

Lasting Lagrange points only exist where two bodies of mass dominate. But in the midst of for example the synchronous Jovian moons, is there a calendar and map for when a spacecraft can be near enough ...
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Would it be possible to Boost ISS to L1 or Lunar Orbit?

NASA and Russia plan to retire the ISS before 2030, and to launch a new lunar outpost to lunar orbit. This output could then be a gateway to future mission to Mars or the outer solar system. My ...
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What would be the delta-v of rendezvousing with temporarily captured asteroids in Sun-Earth L-points?

It is believed that at any point in time, a handful of small asteroids (TCO's) are temporarily orbiting the Sun-Earth Lagrange points 1 & 2. They are random samples from the Asteroid Belt and ...
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Why are the Trojan libration points equidistant and not mass weighted?

The locations of the collinear Lagrange points L1, L2, L3 are mass weighted, so for example Sun-Earth-L1 is only 1% of the distance to the Sun from Earth. But L4 and L5 are one AU from both the Sun ...
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How will JWST maintain its elliptical orbit around L2?

I understand that JWST will have a vertical elliptical orbit around L2, but what I don't understand is how the telescope will actually maintain an orbit if there is no body in L2 to actually orbit ...
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What was the probability that Osiris Rex would find Earth Trojans?

Orbits at the Sun-Earth L4 and L5 (where Earth-associated Trojan asteroids might reside) are not long term stable due to Jupiter's large perturbing effects. Jupiter is about 318 times more massive ...
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How will the Lucy spacecraft move from Jupiter's L4 to its L5 Trojan asteroids?

After having visited the L4 leading Trojans ("Greeks") of Jupiter, almost a decade after launch Lucy will spend almost 4½ years moving on to the trailing L5 Trojans, 5 AU away. Is there a special ...
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Could a radio telescope orbit Earth-Moon L2 so that it is in the Moon's radio shadow?

Chang'e 4, a Lunar orbiter and lander on the far side of the Moon, will put a relay satellite in a halo orbit around EML2 that also will do some low frequency radio astronomy. Since the Chang'e 4 ...
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Delta V to get to the Sun-Earth Lagrange Point 1?

For any of these starting positions, GEO, GTO, EM-L2 or EM-L4/5, which would require the least delta-V to get to Sun-Earth L1? How much delta-V would it require? Would this chart help in identifying ...
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Could a solar sail composed of smart glass stay near the L1 point of Venus?

From answers to this question i've learned that the Lagrangian L$_1$ point of Venus is not stable, despite the almost circular orbit of the planet and the fact that it has no moon. Nevertheless would ...
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Do we have the capability to place a satellite in the Sun-Earth L4/L5 Lagrange points?

I was looking at the Wikipedia page on Lagrangian points, and I noticed that in the list of current and proposed missions, the only mention of the $L_4$ and $L_5$ points is a "this would be a good ...
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Why does DSCOVR's camera EPIC see at least 13 sunrises and sunsets per day?

In this NASA Goddard YouTube video titled "One Year on Earth – Seen From 1 Million Miles", I've gotten stuck on the line In this view, EPIC sees the Sun rise in the west, and the Sun set in the ...
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Is it feasible to put a comet into a Lagrangian point?

How feasible would it be to put a large comet, like the one that Philae landed on, into a Lagrangian point, or some other spot that would make it convenient & SAFE for mining, colonization, ...
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Libration points - Science prospects

There have been quite a few missions to libration points. As far as the dynamical possibilities are concerned, libration point vicinity offers a spectrum of orbit profiles. What science data is not ...
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Is it obvious or easily-proven that L4 and L5 must be in the parental orbital plane?

Looking at the question and answer and diagrams from Are Lagrangian points associated only with the smaller body? got me wondering. L4 and L5 each form an equilateral triangle with the two main ...
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Stationary Inter-planetary Satellite?

Is there a way to place a satellite in-between two planetary bodies such that the force from each gravitational pull is effectively nullified? In other words, is there any type of situation that would ...
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How big would a collection of asteroids near the Moon's L4 point need to be to aggregate naturally into a “stepping stone” for space exploration?

Wouldn't it be useful to catch few meter sized near-Earth asteroids whenever opportunity knocks and "lock them up" at the L4 Langrangian point of our Moon ? Although at the L4 and L5 Lagrangian ...
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Does launching to interplanetary space from LEO require the least delta-v?

Based on this chart from wikipedia, (I do not know if I am reading it correctly) This all assumes LEO-Eq LEO to C3/0=3.22 LEO to GEO to C3/0=3.9+1.3=5.2 LEO to EML-1 to C3/0=3.77+0.14=3.91 LEO to ...
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Is communication from a spacecraft in SEL1 disturbed by the Sun?

A spacecraft at the Sun Earth Lagrange point one (1% of an AU, or one Solar diameter, from Earth towards the Sun) would have the Sun as its background. Is the Sun emitting strongly enough at ...
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Burns for EML-1 to LLO

Wikipedia gives 0.64 or 0.65 km/s for going from LLO to EML-1 or back. I would like to know what the delta v of the specific burns involved are, and if my initial calcs are close, I don't see how ...
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What do the green lines represent in this Lagrange Point animation?

This is one of my all-time YouTube favorite videos. It's an illustration of the Earth-Moon Lagrange points in orbit around the sun for a year. Put on your headphones, dim the lights, and set YT to HD. ...
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Do horseshoe orbits have anything to do with Lagrange points? Do words fail us here?

I said (2010 SO16 is associated with Lagrange point L3 but wanders so far behind and ahead of it that the orbit is called "horseshoe"... and the comment was made: Not really. L3 is unstable. ...
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Details about traveling from EM-L2 to SE-L1

Would the optimal time to launch be when the Moon was on the opposite side of the Earth from the Sun? What direction would be optimal leaving EM-L2, radially away from the moon? Is the last line of ...
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When an object in an unstable Lagrange point falls away from that point, where does it end up? [duplicate]

I know L1-3 are saddle points in the potential, and thus small perturbations would cause an object at one of these points to accelerate away from the point, but where would that object end up? For the ...
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How easy would it be to detect a large 400x1000 meters tubular habitat at L4

I'm writing an SF book and want to know if a 400 by 1000 meter tubular habitat at Lagrange point 4 (or L5) would be easily detected from earth?
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What is a “synodic frame”? Can one be defined for an elliptical orbit?

A description of a "synodic frame" was one of the main ingredients in this excellent answer to a question about an animation of a funky-looking orbit that several different and distinctly interesting ...
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Which lagrange (earth-moon) point is better for a space settlement?

Which among the Earth-Moon Lagrange points (EML1, EML2, EML3, EML4, EML5) is best for a permanent space settlement which requires materials from the moon for construction? Some say it's EML4 for ...
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Is lagrange point L1 stable?

Is Lagrange point L1 stable? If I were to place a space station in L1 will it remain in orbit without any difficulty? If there are any difficulties, please mention them here along with any suggestions ...
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Why has the Earth-Sun libration point L1 been chosen over L2 for NEOCam to detect new NEOs?

above: Profoundly not-to-scale illustration of NEOCam in an orbit around the Sun-Earth libration point L1, about 1.5 million kilometers from Earth. Presumably Sun-shield and Earth-shield block light (...
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How much delta v does it take to get to the Sun-Earth Lagrange 3 point?

How much delta v does it take to get to the Sun-Earth Lagrange 3 point? Also, Would higher delta-v allow a craft to get there much quicker? Would two hohmann transfer orbits be the most efficient ...
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L2 point in multi-moon system

For an SF novel, if there were two large moons orbiting a planet, let's say one moon the size of Earth's moon and the 2nd moon about 20% larger, and the planet roughly the size of the Earth, would the ...
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Did ISEE-3 spend a few years in a halo orbit around sun-earth $L_1$ without using any fuel?

In a related question I'm trying to find some conclusive reference(s) helping explain if some halo orbits around the sun-earth or earth-moon $L_1$ or $L_2$ locations can actually be somewhat stable (...
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from L1 to L2 (earth-sun system) using gravity assistance with the moon

I was wondering if it's possible, when we have a satellite in L1, or going to the L1 direction from the earth, to use a gravity assistance with the moon in order to go in L2. I read that it's possible ...