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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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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This orbit looks wrong near a Lagrange point. Is it?

On a completely unrelated forum, i came across the following graphic: The orbit seems wrong to me, especially the first curve. From the initial trajectory, I would expect the orbit to have been in a ...
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What determines the orbital speed around a massless Lagrangian point?

What value of M should I use to calculate the speed of a satellite orbiting a Lagrangian point where there exists no mass?
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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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Is there a synchronous orbital height for Phobos?

My assumption is that any body in the solar system would have it's own specific geo-synchronous orbit height. But when I took a look at Phobos and calculated the GEO height based on the simple formula ...
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Does the Milky Way have a Lagrangian point? [closed]

About 2.5 million light years from the Milky Way is the Andromeda Galaxy. We have about 4 billion years before the two collide as they approach each other things are getting to get interesting. But ...
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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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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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Can the James Webb Space Telescope basically manage its own orbit if necessary?

In this great answer I learned that the Mars rover Curiosity can be given some tasks and it will go ahead and manage the work and navigation by itself, to at least a certain limit. The James Webb ...
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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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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 this what station keeping maneuvers look like, or just glitches in data? (SOHO via Horizons)

I've been enjoying the JPL Horizons web interface and after I discovered the incredibly extensive database associated with SOHO (Solar and Heliospheric Observatory, also see sohowww.nascom.nasa.gov) ...
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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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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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Are some Halo Orbits actually Stable?

UPDATE: I found another reference! While I always enjoy a good video starring Jimmy and Linda Carter, this one has Dennis Wingo describing ISEE-3's original Halo orbit. He describes Sun-Earth $L_1$ as ...
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Are large halo orbits around L₁'s and L₂'s preferred over small orbits for reasons other than geometry?

There have been many examples of the placement of satellites in orbits around Lagrange points, most have been sun-earth and earth-moon $L_1$ and $L_2$ due to their proximity to earth. In each case ...
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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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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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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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Where will objects end up, after losing stability at Lagrangian points?

The Lagrangian points are points of unstable balance (at least gravitationally; L4 and L5 are stable thanks to Coriolis force.), and that means an object not stabilized actively will fall out of them ...
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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 ...
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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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Why won't JWST deploy in LEO where it is potentially serviceable?

The James Webb Space Telescope will deploy (unfold mechanically) while on the way to L2. Couldn't it do so in LEO, where it is potentially serviceable? Starliner CST-100 and Dragon are planned to soon ...
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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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Low Energy Transfer within Earth-Moon system

Practical aspects of a total low energy transfer to the Moon have been seen in missions like GENESIS, which uses Weak stability Boundary legs of Earth and Sun to reach ESL-2. This four body model ...
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Are there interstellar Lagrange points?

Is there for example some L1 like libration point where the Hill spheres of the Sun and of the Alpha+Beta Centauri meet? And are Lagrange points between stars inside of a binary system, like Alpha and ...
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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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What, if any, libration points exist in systems of multiple orbiting bodies?

Are there libration points in a restricted 4-body problem (system of three orbiting bodies of significant mass, plus the libration point orbiting body)? If so, how many of them exist and where are ...
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What does the Sun-Earth-Moon system look like from the Sun-Earth L-2 point?

The L-2 point of the Sun-Earth system is away from the Earth on the night-side of the Earth; i.e. it's always local midnight at the sub-satellite point. This is an attractive property for some ...
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Halo vs Lissajous orbit: Which station-keeping strategy to select and when?

I'm looking for a comprehensive pros and cons of the two most commonly used station-keeping types of orbits used at libration points, Lissajous and halo orbits. When would one select one over the ...
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Are Sun-Earth Lagrange points SEL1 and SEL2 useful for communication and space surveillance?

SEL1 and SEL2 are about 0.01 AU away, 10 seconds light travel time back and forth, 4 times Lunar distance, 45 times the distance to GEO. From those two regions combined, all surface on Earth and the ...
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How could transfers between SEL1&2 and EML Lagrange points be utilized?

The Earth has 7 Lagrange points nearby since SEL1 and SEL2 (Sun-Earth Lagrange points 1 and 2, respectively) are only between 3 and 5 LD (lunar distances) away from the five EML (Earth-Moon Lagrange) ...
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Are there really just 5 Lagrange points?

In many online resources, like Wikipedia, five Lagrange points are specified. From my understanding, a Lagrange point is a point where the gravitational attractions of the two bodies (Sun and Earth, ...
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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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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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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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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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Single-shot Blue Marble pictures

I was quite surprised to read in today's Earth Observatory Picture of the Day that the DSCOVR spacecraft, currently en route to the $L_1$ Lagrange point, will be the first spacecraft able to see the ...
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Why would a mission to Sun-Earth L1 have an instantaneous launch window?

I was watching the webcast for Falcon 9 Flight 15 (launching DSCOVR) when they scrubbed their first launch attempt due to some issues during the terminal countdown. Before the scrub, the narrator ...
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'Orbiting' Earth-Moon L1

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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What plane will DSCOVR’s orbit be in?

According to the “NASA Earth Science Instruments” section of noaa.gov's DSCOVR page, DSCOVR will make unique space measurements from the first sun-Earth Lagrange point (L1). ... 1.5 million ...
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Reverse Lunar Space Elevator

The possibility of a space elevator from the lunar surface is discussed in this question. A lunar elevator for the purpose of return to Earth could be achieved at the L1 Lagrange Point between Earth ...
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Are there any man-made satellites at Lagrangian points?

There are 5 lagrangian points. Are there any man-made satellites at any of those points? Is there a reason for the presence or absence of satellites at these points?
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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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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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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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Stability of Lissajous orbits around Sun-Venus L1

How far is it from the Venus? Does Mercury gives too big perturbations for a stable Lissajous orbit?
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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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Aren't the mirrors of the James Webb Space Telescope too unprotected?

I've looked at the design of the James Webb Space Telescope and I got curious about something, some years ago, it seems that the international space station was hit by micro-meteorites. I'm wondering ...
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How does gravitational stability change with the distance from special places such as geostationary orbit and lagrange points?

How rapid do the attractive properties of GEO and lagrange points deteriorate with the distance from optimum? How "large" are such locations? At what distance would station keeping require, say, twice ...