Talk:Lissajous orbit

Request for help

Could anyone please read over this article to check for (at least) basic correctness? Thanks! Sdsds 01:31, 24 March 2007 (UTC)

Is this still relevant 11 years later? If so, here are some opinions ....

The lede needs a bit of introduction. Something along the lines of that orbital mechanics allow for Lagrangian points, with a brief resume of what they are. Then... in practice, it is difficult for either man or nature to place an object at *exactly* such a point. However, objects can be placed very closely to those points, and they then execute complex orbits around or near those points. Next it should be explained that the Lissajous nature of those orbits is not easy to visualise, that it needs to be in a rotating frame of reference.

Lyapuniv orbits are a special and much simpler case of Lissajous orbits. Again, diagrams would help. The link pointed to by "Lyapunov orbit" is really too general to be useful. In fact one aspect of Lyapunov orbits doesn't meet one of the general criteria of Lyapuniv stability, and I will have more to say about that over there :D .

None of this is really easy to understand or explain "in words". There are some YouTube videos that show both Lagrangian points and Lissajous orbits. They are very good, but they are not self-explanatory. Copyright permitting, stills from these videos could be used to show the Lissajous nature of the orbits.

The point about "station keeping" needs to be expanded swlightly: spacecraft have to consume fuel to do this, and once they run out, they will drift out of these orbits.

Also, there needs to be a bit of an update. There have been a few asteroids found that co-revolve with the earth (mass media references often say "co rotate" but I'm pretty sure that's wrong) and therefore have Lissajous orbits around the sun. This possibly needs a new small section, perhaps "List of objects in Lissajous orbits with the Earth".

If there's still anyone here, I would appreciate a commentary upon my commentary :D — Preceding unsigned comment added by 121.212.147.109 (talk) 04:24, 3 March 2018 (UTC)

WTF?

I am really interested in space and orbits and orbital mechanics. I have a (non-technical) doctorate degree. That said, I can't make heads or tails of this article. Should't it be written so that a non-scientist can get something out of it? Kjdamrau 03:46, 25 July 2007 (UTC)kjdamrau

Don't worry, I'm a rocket scientist specialized in propulsion and space dynamics and it's all pretty cryptic to me, too. Listing more references would definitely help - especially since the author has an opportunity to check his sources again and doesn't just go from a seemingly sketchy memorization. Nevertheless, good thing that somebody took the effort to start this article. —Preceding unsigned comment added by 71.154.223.244 (talk) 09:26, 16 November 2008 (UTC)

Correctness

I believe the Lissajous orbit is a more eccentric/complicated orbit than a halo orbit. However, the article describes it as non-coplanar in contrast to the halo orbit. The halo orbit is not coplanar to the two main masses (see my last sentence), in fact it's exactly perpendicular to the line between the masses. If the smaller mass were the earth, a halo orbit would trace a 'halo' above the earth around the Lagrange point, hence the name. I'd extend that to say that a Lissajous orbit would be a tilted and/or elliptical halo.

I won't change the article though, as I have a suspicion that my understanding of the use of the word 'planar' isn't appropriate in this context :) —Preceding unsigned comment added by AnitaBSc (talk • contribs) 01:53, August 26, 2007 (UTC)

Ha ha! I think you are right -- that a halo orbit is planar but out of the plane of the two larger bodies' orbits, and that a lissajous orbit is more complicated. I suspect a lissajous orbit may not even be planar, which would explain the strange wording about it being an "orbital trajectory". If only there were an available source for the math involved! (sdsds - talk) 01:57, 8 October 2007 (UTC)

I took the plunge! "Coplanar" was just too confusing. I've replaced it by first describing halo orbits as being in the perpendicular plane, then contrasting the Lissajous orbit. Hope you find this an improvement. Yoyo 124.191.50.199 19:11, 9 October 2007 (UTC)

"Halo vs Lissajous" is a bit more general than that. Both are 3D, so both "bob" up and down in the orbital plane, but as it says, halo is periodic, lissjous are not. There is actually no requirement for either to be planar. To give a quasi example, suppose A and B both orbit X, but A is "big" (eg, Jupiter around the sun), and B is "small"(eg, a co-orbiting asteroid. So B would be in a halo orbit if after only a "few" orbits around the sun, they both returned to the same starting point. Whereas if B is in a lissajous orbit, it will take a "large" number of orbits to return. In fact spacecraft in halo orbits around the earth often return to the same point every year, wherease in contrast, some of the asteroids that have recently been found in kidney-bean or banana-shaped lissajous orbits around the earth may take 50 or 100 years to complete their cycles. — Preceding unsigned comment added by 121.212.147.109 (talk) 04:51, 3 March 2018 (UTC)

diagram

The current diagram being used here is actually showing how to reach a Lissajous orbit, not the orbit itself. --Lasunncty (talk) 19:20, 20 December 2013 (UTC)

I think we could also benefit from having a diagram that shows all the points, as opposed to just L2. --Goatonastik (talk) 20:05, 17 March 2017 (UTC)

SOHO?

The Halo orbit article lists SOHO as being the second spacecraft to achieve a Sun-Earth L1 halo orbit. It's also listed here. Has its orbit type changed? 165.225.38.204 (talk) 13:38, 27 October 2017 (UTC)

According to the Earth Observatory Portal, SOHO is incorrectly listed here as having a Lissajous orbit. The site explicitly refers to SOHO's orbit as a halo orbit and includes a schematic diagram of the orbit (https://directory.eoportal.org/web/eoportal/satellite-missions/s/soho).165.225.38.204 (talk) 14:10, 27 October 2017 (UTC)

Trojan Asteroids of Jupiter.

These asteroids are normally described as being "at" the L4 and L5 Lagrangian points. To be pedantic, that is only an approximation. More precisely, they in fact execute Lissajous and halo orbits around these points, with an enormous range of amplitudes. — Preceding unsigned comment added by 58.166.224.167 (talk) 00:32, 3 March 2018 (UTC)

A grand illustration of the odd trajectories of Lissajous orbits

This simple animated graphic is an awesome illustration of quite a large number of the (apparently, quite odd) trajectories that can be seen in Lissajous orbits. Lissajous orbit diversity, illustrated

This video] describes a couple of mathematicians who have done good illustrations of this type, as well as how a freeware (free software) program called "geogebra" that can facilitate drawing these Lissajous figures.

Would be helpful if someone would care to generate a Creative Commons-licensed animated graphic for Wikipedia. N2e (talk) 14:32, 17 June 2021 (UTC)