Linked Questions

22 votes
5 answers
6k views

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
  • 22.9k
11 votes
4 answers
2k views

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 ...
uhoh's user avatar
  • 149k
14 votes
3 answers
9k views

How to best think of the State Transition Matrix, and how to use it to find periodic Halo orbits?

I'll state my mathematical question about the state propagation and state transition matrices first, then show you a simple problem for which I would like to use these concepts to generate a densely ...
uhoh's user avatar
  • 149k
17 votes
4 answers
4k views

Are some Halo Orbits actually Stable? (stable orbits about unstable Lagrange points)

update: some more sources; the broken site spacecraftforall.com/a-new-orbit used to have an interactive simulation, here's an old screen shot: Hat tip to @NgPh for finding this Space College page ...
uhoh's user avatar
  • 149k
10 votes
2 answers
3k views

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 ...
Ng Ph's user avatar
  • 2,749
14 votes
1 answer
2k views

What sort of orbital elements are used to describe halo orbits?

For standard orbits we can use Keplerian elements, TLE, or other similar. These don't make much sense for Halo orbits, which are not around a central body, but around a Lagrangian point, and follow an ...
SF.'s user avatar
  • 55.1k
18 votes
1 answer
1k views

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 ...
TildalWave's user avatar
  • 76.2k
6 votes
1 answer
482 views

Why put DSCOVR in a Lissajous orbit? Wouldn't a halo orbit completely avoid the Sun exclusion zone?

Halo orbits are a sub-class of Lissajous orbits. See this answer for (much) more on that. DSCOVR's orbit will put it in it's Sun Exclusion Zone in about 2020 where the communications line of sight ...
uhoh's user avatar
  • 149k
4 votes
2 answers
342 views

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
  • 149k
5 votes
1 answer
334 views

Where did the Herschel Space Telescope go in 2013?

The Herschel space telescope wins as largest optical telescope mirror in space when "optical" includes far infrared (~55 µm). The Wikipedia article Herschel Space Observatory lists the orbit ...
uhoh's user avatar
  • 149k
4 votes
1 answer
444 views

Do ("non-halo") Lissajous orbits have stable/unstable manifolds?

The question Did DSCOVR travel “along the stable manifold of its future SE L1 Halo orbit” to get there? is specific to DSCOVR's trajectory from Earth to its primarily heliocentric orbit near Sun-Earth ...
uhoh's user avatar
  • 149k
5 votes
0 answers
443 views

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 ...
nealmcb's user avatar
  • 761
2 votes
1 answer
238 views

Why Euclid's orbit is not like Gaia but like JWST?

Euclid, Gaia and JWST are all orbiting Lagrange Point L2. Why is Euclid's orbit similar to JWST but not Gaia's, why is Gaia's orbit different than Euclid and JWST ? Orbits are shown here for example:
Mete's user avatar
  • 141
3 votes
1 answer
262 views

Was Queqiao in a halo or Lissajous orbit? Why do sources disagree?

Wikipedia's Lissajous orbit says that sources disagree on the nature of Queqiao relay satellite's orbit; if it was in a proper halo orbit or just a Lissajous orbit. Proper halo orbits have the same ...
uhoh's user avatar
  • 149k
2 votes
0 answers
161 views

Difference between approach maneuvers to the insertion points of halo and Lissajous orbit?

I have read that spacecraft use two mid-course corrections to approach the Lagrange point, then do a final orbital insertion maneuver to enter into a halo orbit. Are there any specifics about this ...
Bob516's user avatar
  • 6,999

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