Do you need help with SPICE?

[selden]

One of my acquaintances just discovered Celestia.

He works in Cornell's Space Sciences department and has quite a bit of professional experience with spacecraft trajectories and creating SPICE kernels. Although he probably won't be visiting the Forum often, if at all, he has volunteered to help people with problems they encounter when creating or using SPICE kernels for Celestia.

Please contact me if you'd like his assistance.

[Langrenus]

I am so glad I found this posting. I just posted the following in the “help central” section of shatters.net, of which I am happy to be a brand new member. The question I posed is as follows:

I have a question involving orbits of certain add-on spacecraft.

Did the Apollo spacecraft, upon entering lunar orbit, approach the Moon from its western hemisphere, leading the Moon in its orbit around the Earth, or from its eastern hemisphere, trailing behind the Moon in its orbit of Earth?

I have always thought it was the former, but the two Apollo spacecraft add-ons I have for Celestia tell the opposite story; they orbit in a counterclockwise direction, as seen from above the lunar North Pole. An approach to the lunar surface from that direction would have placed the sun right in the eyes of the astronauts as they prepared for landing.

Since both of my Apollo 11 add-ons seem to be orbiting in the wrong direction, my question is, can I change the parameters of the orbit in order to correct that? Otherwise, I am afraid my Apollo experience with Celestia, despite the beautiful graphics, will have lost all its charm.

Thank you to anyone who chooses to reply to my question.

The two add-ons in question are:

Apollo_11 (downloaded from the Motherlode)

Apollo 11 prerelease (containing [EC_pre_CSM] and [EC_pre_LEM_Descending] that I downloaded from http://www.CelestialMatters.org)

The latter is a beautiful rendition of the Apollo spacecraft that I intended to attempt to create an Apollo 12 mission script for. I planned to tweak the orbit (I am very new at this) so that the scenario was as accurate as I could possibly make it. It was then that I discovered that the spacecraft is moving in the opposite orbital direction to what it should be. It matches the orbital direction for a typical Earth orbit, so I can understand why something may have been overlooked.

I do not know if it is possible to make the necessary changes to accommodate what I would like to do, but perhaps you or your friend could help me out with my problem.

Thanks ever so much!
Absolutely LOVE Celestia!