View source for Libration point orbit

{{Short description|Quasiperiodic orbit around a Lagrange point}}
In [[orbital mechanics]], a '''libration point orbit''' (LPO) is a [[quasiperiodic motion|quasiperiodic]] [[orbit]] around a [[Lagrange point]]. [[Libration]] is a form of orbital motion exhibited, for example, in the Earth–[[orbit of the Moon|Moon]] system. [[Trojan (celestial body)|Trojan bodies]] also exhibit libration dynamics.

Two varieties of libration point orbits amenable to [[Lyapunov stability]]{{clarify|reason=stub author has only the haziest idea how this concept relates to the following exemplars, but the shoe seemed to fit|date=September 2022}} are [[halo orbit]]s and [[Lissajous orbit]]s<ref name=Pergola2012>{{cite journal
   |last1=Pergola
   |first1=P.
   |date=21 October 2012
   |title=Libration point orbit characterization in the Earth-Moon system
   |url=https://academic.oup.com/mnras/article/426/2/1212/974113
   |access-date=20 September 2022
   |journal=Monthly Notices of the Royal Astronomical Society
   |volume=426
 |issue=2
 |pages=1212–1222
 |doi=10.1111/j.1365-2966.2012.21585.x
|bibcode=2012MNRAS.426.1212P
 |s2cid=122979904
 }}</ref>

The [[James Webb Space Telescope]] (JWST) is in a libration point orbit around the L2 Lagrange point of the Sun, and Earth-Moon [[barycenter]]s.<ref name=Greenhouse2011>{{cite book
   |last1=Greenhouse 
   |first1=Matthew
   |title=2011 2nd International Conference on Space Technology
 |chapter=The James Webb Space Telescope: Mission overview and status
 |date=October 2011
   |chapter-url=https://www.researchgate.net/publication/224265228
   |access-date=20 September 2022
   |pages=1–4
 |doi=10.1109/ICSpT.2011.6064655
|hdl=2060/20090026783
 |isbn=978-1-4577-1874-8
 |s2cid=1957332
 |hdl-access=free}}</ref><ref name=Dichmann2014>{{cite journal
   |last1=Dichmann 
   |first1=Donald J.
   |date=5 May 2014
   |title=Stationkeeping Monte Carlo Simulation for the James Webb Space Telescope
   |journal=International Symposium on Space Flight Dynamics Conference Proceeding 
   |doi=<!-- document ID 20140007519 -->
|s2cid=51732847
 }}</ref> Because libration point orbits are quasiperiodic, the telescope must make frequent small [[rocket engine|burns]] to maintain proximity to the L2 point, as part of [[orbital station keeping]], limiting the lifespan of the telescope due to depletion of fuel reserves.

Early simulations of the JWST obtained a high confidence in achieving a ten-year operational lifespan before station keeping becomes untenable.<ref name=Dichmann2014/> However thanks to a highly accurate launch, it is now thought the telescope could keep its station for up to twenty or even twenty-five years. Some years of intermittent service after that might also be tenable, because of the slow drift rate out of, or from towards, the Lagrange point.

==References==
{{Reflist}}

[[Category:Orbits]]


{{Orbits|state=expanded}}{{Astrophysics-stub}}