# Talk:Sun-synchronous orbit

WikiProject Spaceflight (Rated C-class, Low-importance)
This article is within the scope of WikiProject Spaceflight, a collaborative effort to improve the coverage of spaceflight on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C  This article has been rated as C-Class on the project's quality scale.
Low  This article has been rated as Low-importance on the project's importance scale.
WikiProject Astronomy (Rated C-class, Low-importance)
Sun-synchronous orbit is within the scope of WikiProject Astronomy, which collaborates on articles related to Astronomy on Wikipedia.
C  This article has been rated as C-Class on the project's quality scale.
Low  This article has been rated as Low-importance on the project's importance scale.
WikiProject Solar System (Rated C-class, Low-importance)
This article is within the scope of WikiProject Solar System, a collaborative effort to improve the coverage of the Solar System on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C  This article has been rated as C-Class on the project's quality scale.
Low  This article has been rated as Low-importance on the project's importance scale.

## ARTICLE OPENING IS FULL OF SELF-ABSORBED TECHNOSPEAK

When you write about science for the general public you have a responsibility to communicate in a way that the average non-scientist lay person can understand. This is also Wikipedia policy--

Once the public service mission of the article is satistied, one may also then include highly technical language in parallel to the non-technical writing. But only after the plain English requirements are met, unless a lay translation is virtually impossible.

This is good practice anyway for people in the science fields, because if you want your own work to be funded, you had better know how to communicate the key aspects of what you are doing in plain English, free of self-absorbed techno-babble. Otherwise you might eventually lose public support and funding for your work. Plus it's just plain inconsiderate to write a science article on a public-service platform that can not be understood by the general public. 64.134.125.77 (talk) 08:31, 16 December 2013 (UTC)

## Heliosynchronous orbit

Yes indeed why would Heliosynchronous be wrong to say? It has the exact same meaning... —Preceding unsigned comment added by 83.254.5.198 (talk) 19:16, 8 February 2008 (UTC)

Is the article correct in saying that the term "heliosynchronous orbit" is rarely used relative to "sun-synchronous"? In my mild experience reading and studying physics, just the opposite is true. —The preceding unsigned comment was added by 128.206.231.43 (talk) 06:44, 24 January 2007 (UTC).

See Heliosynchronous orbit —Preceding unsigned comment added by 79.199.115.206 (talk) 12:35, 21 June 2009 (UTC)
No, it is a made-up term, see the discussion on the Talk Page at the Talk:Heliosynchronous orbit. Cheers. N2e (talk) 14:28, 9 July 2012 (UTC)

## dynamical form factor

The equation for J2 is misleading at best. J2 is not defined with respect to the Earth's rotation rate, and the precession rate does not depend directly on this rate. —Preceding unsigned comment added by Optiker (talkcontribs) 10:59, 6 March 2008 (UTC)

Stamcose (talk) 08:13, 21 June 2011 (UTC)

## Sun-synchronous orbit

(1) The right-hand side of the cos(i) = RHS equation on page 2 has an error that makes it useless. Move the (square-root of mu) factor from numerator to denominator to correct the error. A units analysis of RHS will also reveal existence of the error, noting that cos(i) is unitless.

(2) Insert factor ((1-(e squared))squared) on RHS to upgrade to non-zero eccentricity.

(3) It should be mentioned that this equation is derived (after corrections named above) from secular perturbative analysis (e.g., see Herrick, Astrodynamics, Vol. 2, pages 216 and 195 for J), and does not provide evaluation of physical effects due to the osculating orbit. —Preceding unsigned comment added by 65.89.177.1 (talk) 17:35, 24 May 2011 (UTC)

The dimension of
$\sqrt{\mu}\ a^{\frac{7}{2}}\,$ is $km^5\ s^{-1}\,$
The dimension of
$\rho\,$ is $s^{-1}\,$
The dimension of
$J_2\,$ is $km^5\ s^{-2}\,$
Please ignore the unsigned comment above!

Stamcose (talk) 08:09, 21 June 2011 (UTC)

The formula is seriously in error and needs to be corrected. J2 is supposed to be dimensionless! — Preceding unsigned comment added by 216.186.244.247 (talk) 06:26, 5 February 2014 (UTC)

## "Heliosynchronous orbit" as an equivalent term for Sun-synchronous orbit is unsourced

There is no source in the article for the claim that Heliosynchronous orbit is the same thing as Sun-synchronous orbit. I have tagged the claim as needing a citation. If one is not forthcoming, I will remove the claim shortly.

In the meantime, if you want to see why there is likely no claim, and that Heliosynchronous orbit is an invented term, possibly inadvertantly through Wikipedia, see the discussion underway at Talk:Heliosynchronous orbit. Cheers. N2e (talk) 14:32, 9 July 2012 (UTC)

## Dubious

I think that the mean motion of the Earth about the Sun is 360° per sidereal year, not tropical year. Sidereal year is the time taken by the Earth to orbit the Sun once with respect to the fixed stars. — Petr Matas 09:09, 22 February 2014 (UTC)