Questions tagged [halo-orbit]

Questions regarding co-orbital orbits in a three body system.

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How well is JWST doing on maintaining its Halo orbit?

I looked around a little bit online but did not find anything discussing how well JWST is doing with managing its orbit. I was wondering if there were any surprises or issues. It's been out there ...
BradV's user avatar
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Why is the Sun influence a mere perturbation to the Moon NRHO (the orbit the Gateway should be put in the context of project Artemis)?

An article of the relevant literature Heliocentric Escape and Lunar Impact from Near Rectilinear Halo Orbits asserts: "As the spacecraft departs the immediate vicinity of the NRHO, the effects of ...
Franklin's user avatar
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Visualizing halo orbits

I'd like to visualize JWST's orbit (or any halo orbit that resembles it) preferably in Python. Does anyone have any code or resource I could read? Thanks in advance!
Alvaro's user avatar
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Would it be practical to position a telescope like JWST at Sun-Earth L4 or L5?

During a discussion of Lagrange points I was asked why we didn't put JWST at SE L4 or L5 since they are less unstable than L2. I thought a bit and came to think that the Earth gravity driven Halo ...
BradV's user avatar
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What are "transcritical, pitchfork, period-doubling, torus, and subharmonic bifurcations" in the context of three-body orbits? (e.g. butterflies)

MattB's excellent and well-sourced answer to Where do the butterflies land on this bifurcation plot? (Earth-Moon three-body butterfly orbits) begins: I'm fairly certain that the butterfly family is ...
uhoh's user avatar
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How frequent are (or will be) JWST station keeping burns at L2?

Does anyone have solid information regarding the scheduled/anticipated station keeping burns for JWST at L2? In an online video I've heard mention of 'every 21 days' which at first look seems ...
BradV's user avatar
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1 vote
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Where do the butterflies land on this bifurcation plot? (Earth-Moon three-body butterfly orbits)

Below is a $\mu = 0.01215$ bifurcation plot from E. J. Doedel, E.J. et al's Elemental periodic orbits associated with the libration points in the circular restricted 3-body problem International ...
uhoh's user avatar
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Code to generate Sun-Earth L2 halo orbits for given epoch?

I am working on a GMAT script out of personal interest (not part of a job) that involves a spacecraft orbiting the Sun-Earth L2 point. I have found some orbital state vectors for the spacecraft that ...
kardalos's user avatar
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Where is Artemis on this Earth-Moon three-body bifurcation plot? Where's the near-rectilinear halo orbit for example?

Below is a $\mu = 0.01215$ bifurcation plot from E. J. Doedel, E.J. et al's Elemental periodic orbits associated with the libration points in the circular restricted 3-body problem International ...
uhoh's user avatar
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5 votes
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Planet Orbit "swept Area" Vs halo orbit "swept area"

After plotting the JWST halo orbit to a flat plane, and finding that the halo appears to closely approximate an ellipse (yes, the halo has some 'potato chip' warping) I began to wonder. A planetary ...
BradV's user avatar
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Is the JWST halo orbit period sync'd with earth's elliptical orbit about sun?

I was looking at the JWST halo and wondering if getting the halo orbit phased with earths elliptical orbit would be a way of keeping gravitational variations regular and periodic so that station ...
BradV's user avatar
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4 votes
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Does anyone here have a recognized definition of North, South, Class1, Class2 Halo orbits?

Question: What makes a halo orbit North or South, Class 1 or 2 In going thru various sites and papers I've come across lots of discussion of halo orbits being Northern, Southern, Class 1, Class 2. but ...
BradV's user avatar
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4 votes
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Is this JWST Halo orbit plot fouled up somehow?

After looking at this plot and many others I've come to the conclusion that this plot does not represent current JWST halo orbit. If the plot is supposed to be of JWST halo... it disagrees with many ...
BradV's user avatar
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5 votes
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Are L1 and L2 orbital periods always half the orbital period of the massive bodies?

Are L1 and L2 libration point orbital periods always half the orbital period of the massive bodies? The halo orbital period of JWST is a half a year. https://webb.nasa.gov/content/about/orbit.html The ...
Woody's user avatar
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With independent control of attitude and thrust direction, could JWST be kept pointing in a “safe” direction during "towing"?

Context: JWST is considered un-repairable in its current L2 location for a number of reasons: Diagnosis is difficult since JWSR has no “selfie” capability. This makes planning for any repair mission (...
Woody's user avatar
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Halo Orbits for Dummies: Can the tilt orientation of an L2 halo orbit be modelled on Coriolis Effect?

L2 Halo orbits are often portrayed as a pair of “North” and “South” orbits. Could the difference in “tilt” around the Y axis be explained by the direction of rotation and the Coriolis Effect? https://...
Woody's user avatar
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JWST Halo Orbits for Dummies: can halo orbits be usefully approximated by Simple Harmonic Motion?

Halo Orbits for Dummies: can halo orbits be usefully approximated by Simple Harmonic Motion? I am an undergraduate in the Kerbal Academy of Astrodynamics. Patched conics have given me an intuitive ...
Woody's user avatar
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How is the moon's orbital motion accounted for in determining the best observation platform/location for JWST at L2?

The moon's periodic motion would appear to impose a perturbation to the otherwise equilibrium state of the solar/earth L2 point.
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Is JWST actually in a Lissajous orbit? What will it look like? Implications for station-keeping?

Note: for lots of great background related to this question, see lagrangian points - The design of the halo orbit of the James Webb Space Telescope - Space Exploration Stack Exchange There are ...
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Why are eclipses of the James Webb by the Earth or Moon not permitted during the mission?

Why are eclipses of the James Webb Space Telescope (JWT) by the Earth or Moon not permitted during the mission? In Seasonal variations of the James Webb Space Telescope orbital dynamics it is stated ...
Woody's user avatar
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10 votes
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The design of the halo orbit of the James Webb Space Telescope

As I feel a little less uncomfortable with "halo" orbits, with this question, I would like to explore the practical aspects, in particular those related to the design of the James Webb Space ...
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18 votes
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James Webb telescope; limits to propellant lifetime?

There is a comprehensive article on Wikipedia on the James Webb telescope. It includes a statement regarding the operational lifetime being nominally five years and optimistically ten years. However ...
Roger Wood's user avatar
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6 votes
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Is there a fairly detailed outline of CAPSTONE's "highly efficient ballistic lunar transfer trajectory" from LEO to lunar near-rectilinear halo orbit?

NASA Ames's feature CAPSTONE’s CubeSat Prepares for Lunar Flight says CAPSTONE will use a hydrazine-fueled propulsion system during most of its three- to four- month journey to the Moon. This line of ...
uhoh's user avatar
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4 votes
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Can mascons have Lagrange-like points? In principle? At the Moon?

Background Lagrange points are a mathematical consequence of the The Circular Restricted Three Body Problem (CR3BP or CRTBP); two massive bodies orbiting around their center of mass and a third ...
uhoh's user avatar
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1 vote
1 answer
128 views

Could there be a relatively stable near-rectilinear halo orbit associated with the Sun-Earth L1 or L2 points? Would the Moon screw it up?

Question: Could there be a relatively stable near-rectilinear halo orbit (NLHO) associated with the Sun-Earth L1 or L2 points? Would it be similarly stable as the Earth-Moon NLHO proposed for the &...
uhoh's user avatar
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2 votes
1 answer
161 views

Nickname and citation for famous, historic three-body spacecraft trajectory design "manual"; something like "DoKaRoMo"?

There is a heavily-cited work about the use of three-body orbits with four authors, I think some at NASA at the time. I know that I've cited this abbreviation in my own posts a few times, but I can't ...
uhoh's user avatar
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4 votes
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Station-keeping delta-v per year for an Earth-Moon vanilla halo orbit?

This answer reminds us that an Earth-Moon L1 or L2 vanilla1 halo orbit remaining always visible to some patch on the Moon's surface requires station-keeping. Queqiao uses such an orbit having ...
uhoh's user avatar
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8 votes
3 answers
622 views

Why shouldn't we illustrate spacecraft trajectories on top of static zero velocity pseudo-potential surfaces?

Three-body spacecraft orbits1 are regularly discussed here and from time to time someone will include a pseudo-potential plot from Wikipedia in their explanation. The discussion often goes south when ...
uhoh's user avatar
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8 votes
1 answer
429 views

Thrown-together $200 million mission to asteroid 2020 SO; check out or nudge to longer-lasting mini-moon orbit

This tweet says in part: Earth's potential new minimoon, 2020 SO may be the Surveyor 2 Centaur rocket body, launched in September 1966. Integrating backwards shows 2020 SO2 to also be orbiting Earth ...
uhoh's user avatar
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0 votes
0 answers
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Is a 2:1 "figure-eight" Lissajous orbit possible in the Circular Restricted Three Body Problem?

Was Queqiao in a halo or Lissajous orbit? Why do sources disagree? says Proper halo orbits have the same period for their in-plane oscillations and out of plane oscillations, so they are closed ...
uhoh's user avatar
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10 votes
3 answers
3k views

Why aren't energy and momentum (of a restricted three-body system) conserved, or are they?

The question Is the Jacobi constant stationary along a periodic orbit? lead me to Wikipedia's Jacobi integral, which begins: In celestial mechanics, Jacobi's integral (also known as the Jacobi ...
uhoh's user avatar
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2 votes
1 answer
304 views

Is the Jacobi constant stationary along a periodic orbit?

In the book called "Chaotic Worlds: from Order to Disorder in Gravitational N-Body Dynamical Systems", link here, the author states that if the dynamical system has an integral of motion which is not ...
John's user avatar
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8 votes
1 answer
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What is the physical interpretation of the eigenvalues of the monodromy matrix and how are they associated with the invariant manifolds?

To define the monodromy matrix, assume that the period for one cycle of a halo orbit is denoted as $T$, the initial time as $t_0$, and the state-transition matrix is defined as $\phi$. Then, the ...
John's user avatar
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4 votes
2 answers
537 views

Are there some three-body orbits that can't be escaped? Can we know without propagating forever?

update: Searching for "choreographies" I found this Physics SE question which is related but different because it asks only if periodic solutions can be proven to be periodic numerically and my ...
uhoh's user avatar
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1 vote
0 answers
51 views

When will DSCOVR appear too close to the Sun for reliable downlinking?

DSCOVR is in a Lissajous orbit about the Sun-Earth L2 point. That the orbit is called Lissajous rather than halo means that it's periods of horizontal libration and vertical libration are not equal. ...
uhoh's user avatar
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2 votes
0 answers
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How can you construct the periodic orbits around libration points L1 and L2 in the circular restricted three-body problem and prove their existence?

Following up on a previous question about the classification of periodic orbits, how can they be constructed, especially the planar Lyapunov family, around libration points $L_1$ and $L_2$? And how ...
John's user avatar
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8 votes
1 answer
570 views

How does a butterfly orbit move in 3D? Way to generate or visualize?

The paper Earth-Moon Near Rectilinear Halo and Butterfly Orbits for Lunar Surface Exploration (AAS 18-406) says Periodic Orbits in the Earth-Moon System The current investigation focuses on three ...
uhoh's user avatar
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4 votes
1 answer
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Do Lagrange points still exist if there is significant radiation pressure on the third body from the first?

From this answer: To obtain the distance to L1, find the smallest value of $r$ such that $$\frac{M_2}{r_1^2} + \frac{M_1}{R^2} - \frac{r_1(M_1+M_2)}{R^3} - \frac{M_1}{(R-r_1)^2} = 0.$$ To obtain the ...
uhoh's user avatar
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5 votes
1 answer
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Can L3 have halo orbits?

I've recently said you see one co-linear libration point, you seen 'em all. That's what I always say and while halo and other orbits associated with Sun-Earth L1 and L2 work similarly, L3 is 2 AU ...
uhoh's user avatar
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7 votes
3 answers
3k views

Does Kerbal Space Program have a software migration path to Lagrange points, halo orbits, and other 3-body goodies?

At about 05:37 in Scott Manley video Kerbal Space Program 2 - What We Know About The Sequel So I’m cautiously optimistic and I really obviously want this to be ...
uhoh's user avatar
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9 votes
1 answer
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How would you identify when an object in a Lissajous orbit needs station keeping?

Obviously, with the international space station you need to do some station keeping when you're falling into the atmosphere. However, I saw the following image showing the Halo orbit that the Deep ...
Magic Octopus Urn's user avatar
5 votes
1 answer
357 views

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 from ...
uhoh's user avatar
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2 votes
0 answers
242 views

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 ...
uhoh's user avatar
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6 votes
2 answers
359 views

Is the Gateway's halo orbit bound to Earth? Would the Gateway remain in Earth orbit if 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. ...
uhoh's user avatar
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3 votes
0 answers
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Which two spacecraft have spent the longest times in libration point orbits? (Lagrange points, Halo, Lissajous, etc.)

Libration point orbit is a general term including halos, Lissajous', and a whole zoo of others associated with Lagrange points in three-body systems. Which two spacecraft has been in such an orbit ...
uhoh's user avatar
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7 votes
3 answers
3k views

What is the required burn to keep a satellite at a Lagrangian point?

When a satellite reaches a Lagrangian point, it has a non-zero velocity $v_1$ because of the transfer orbit in which it had already been. What burn, say, $\Delta v$, one needs if the satellite is ...
user avatar
17 votes
4 answers
5k views

Could JWST stay at L2 "forever"?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
user721108's user avatar
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3 votes
1 answer
711 views

Rendezvouses in halo or lissajous orbits

If a spacecraft was in an EM-L2 halo/lissajous orbit, and another craft would was going to approach EM-L2 a few days later, could they rendezvous immediately or is there a limitation when the second ...
Bob516's user avatar
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4 votes
1 answer
882 views

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 ...
Jesseseamans's user avatar
1 vote
0 answers
43 views

Total amount of torques and forces in Lunar L2 Halo orbits

I want to design a spacecraft control systems around Earth-Moon L2 Halo orbits but at the first place, I want to have an estimation about the total torques and forces which the control devices should ...
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