Talk:Orbital perturbation analysis

Expert tag - removed
In http://en.wikipedia.org/wiki/Template:Expert-subject

it is said:

''Important: After adding this template to an article, please state on the article's talk page the issue that you think an expert needs to address. Unexplained expert tags may be simply removed.''

As this has not been done I remove the tag.

Any expert is invited to access the article but it must be pointed out that this is the theory built into the flight-dynamics software used for the operations of for example the Sun-synchronous spacecraft ERS-1, ERS-2 and Envisat. And many other spacecraft!

Stamcose (talk) 11:41, 16 March 2011 (UTC)

Can we remove some of the tags now?
I added an introductory section to the article, and reworded some of the copy to make it more readable. I would like to remove the copyedit and context tags, but would appreciate it if someone else would confirm that the tags should be removed. Target drone (talk) 23:28, 10 June 2012 (UTC)

First section wrong
Concerned that parts of the first section is wrong: "Isaac Newton determined the primary contributing factor to orbital perturbation of the moon was that the shape of the Earth is actually an oblate spheroid due to its spin, and he used the perturbations of the lunar orbit to estimate the oblateness of the Earth." I can find no evidence for this. Newton recognised that the tides caused by the Moon were oblate spheroid, the Earth was an oblate spheroid, and this would mean it was gravitation was not a simple point source. But he also understood the major impact on the Moon's orbit is the Sun. Oblate spheriodness is not mentioned in the Lunar theory article. Also no evidence for the statement "Newton recognized that the Moon's perturbations could not entirely be accounted for using just the solution to the three body problem, as the deviations from a pure Kepler orbit around the Earth are much larger than deviations of the orbits of the planets from their own Sun-centered Kepler orbits, caused by the gravitational attraction between the planets." Three body problem has never been solved. Fair enough to point out that astronomical perturbation are dominated by other bodies, whereas for spacecraft oblateness (and atmospheric drag and solar pressure are important as is done later in the article, but these statements are unfounded. If not objection I will remove - they are not essential to the article.Marqaz (talk) 19:11, 28 November 2016 (UTC)
 * your comment seems to be missing a ')' in the last 2 lines. I hope you agree we should still mention air drag and solar radiation pressure. I've marked the Newton statements as dubious for now. - Rod57 (talk) 11:08, 8 April 2017 (UTC)

Only about analysis - not prediction
Is this article just for analysis (as it says), to work out perturbations from orbits, or also to include calculation of orbits from known perturbations ? - Rod57 (talk) 11:27, 8 April 2017 (UTC)

Title refers to spacecraft but text refers to the Moon which is not a spacecraft.
These are two types of perturbation analysis that use the same equations and force models but in a very different context. Orbital perturbation analysis of spacecraft is usually done in order to evaluate the implications for the mission and to predict, plan and minimize the need for orbit maintenance. The motivation for Perturbation analysis of celestial bodies on the other hand (where there is no ability to control the orbit) is to identify the deviation of the actual orbit from the simpler Keplerian model in order to quantify the errors in using the simplified model and to describe the short term (osculating) and long term (mean) evolution of the orbit. For example, long term perturbations to Earth's orbit lead to https://en.wikipedia.org/wiki/Milankovitch_cycles Annette Maon (talk) 12:56, 7 July 2018 (UTC)

Merge with other article?
It seems like this article should be merged due to its significant overlap with similar article(s). I propose merger with https://en.wikipedia.org/wiki/Perturbation_(astronomy), which also redirects from 'orbital perturbation', but there might be an even better option. Please discuss on https://en.wikipedia.org/wiki/Talk:Perturbation_(astronomy). I will add merge tags. Zerohourrct (talk) 00:04, 17 August 2018 (UTC)

formula mismatch
I'm trying to reconcile the earth's induced perigee precession formula (eqn #28) with one from Bryson: dw/dtheta = ... (3/2)J2(2-2.5sin^2(i))(Re/p)^2 The 2pi is understood as swapping d(theta) for a whole orbit period T, but leaves me with p^2/mu = 1, in other words I can't reconcile. Bryson is likely to have made an approximation, but his is at least dimensionally correct... — Preceding unsigned comment added by 174.216.12.220 (talk) 16:28, 3 August 2019 (UTC)