Celestia Forums

Hello all,
I am trying to get together Celestia with SPICE support to have an idea when MRO is visible from earth.. so I installed a recently CVS compiled version for win32.. the executable is 2.5 MB large so I suppose the SPICE libraries are included. I created MRO.ssc and downloaded the bsp SPICE files as described by symaski62 [url=http://www.celestiaproject.net/forum/viewtopic.php?t=10112&start=30] here [/url] but still, I cannot find MRO in the Celestia program.. and yes, I was looking in the right time frame, specified by the bsp files..

Any ideas? I am sure, I am missing something very simple..

Reason to look for orbital data: I would like to compare with actual AOS/LOS of MRO.

Thanks!
Achim, DH2VA/HB9DUN

If the cvs version was installed by the setup I provided in the developers forum, Win-cvs version setup.exe installer.

I did not enable Spice Support.

cartrite

You will only find MRO in Celestia if you yourself defined that object name in your SSC catalog file. Did you?

Please post a copy of the SSC file that you created as well as the exact source and name(s) of the SPICE kernels that you downloaded.

Note that you also must specify in the SPICE orbit definition the spacecraft name or spacecraft number that is defined in the SPICE kernel. Often the name or spacecraft number specified in the kernel isn't what you might expect.

Hello..

I made an exact copy and paste of the MRO.ssc from symaski62 file in the post I mentioned in my question. The bsp files have the names given in the ssc file.

Actuelly MRO is called Spice_MRO in the file.. but it cannot be found in Celestia.

The version I installed was the precompiled verion of malenfant (1.5.0) Could this be the problem?

Achim

dh2va wrote:Hello..

I made an exact copy and paste of the MRO.ssc from symaski62 file in the post I mentioned in my question. The bsp files have the names given in the ssc file.

Actuelly MRO is called Spice_MRO in the file.. but it cannot be found in Celestia.

The version I installed was the precompiled verion of malenfant (1.5.0) Could this be the problem?

Achim

ok http://www.purebytes.de/stuff/celestia/ update 10/24/2006

Dear all,
installed again first 1.4.1. , then the recently compiled version just mentioned here and again MRO.ssc and the SPICE Files.. nothing to see.


Do I have to switch on something else?

Sorry for these stupid questions..

Achim

Does a non-Spice MRO SSC file work for you?

Too often these problems are caused by typos that aren't obvious until you compare a working version with a non-working version.

Using someone else's example won't always work if you aren't using exactly the same versions of the software, especially when the code is in rapid flux, as it is now. You need to understand what is actually going on to figure out what's failing.

In other words, you should try to create a SPICE SSC yourself by following the descriptions available and build Celestia from the code currently available from SourceForge. Doing anything else is likely to be a waste of time.

Dear Selden,
hmm.. this sounds more complicated than I expected.. I am one of the 'dumb' windows users who don't even have a c compiler.. So I will have to wait for a compiled version with Spice support and a SPICE data set.

That said, could maybe anybody just zip his spice-working Celestia subdir and I will try this here?

Cheers,
Achim

Achim,

Have you looked at Celestia's console log? That sometimes can tell you what's going wrong.

Type a tilde (~) to see it while Celestia is running. On a European keyboard you may have to type a space after the tilde. Use the up/down arrow keys to look at earlier messages. You also should remove all other Addons. Otherwise status messages from those others will hide the one or two lines that are due to the one that has a problem.

Could you post your ssc file for MRO? I'm wondering if you might just need to add Beginning and Ending fields to set the range of your SPICE orbit. For example, this would set the valid range to be midnight Oct 1, 2006 to noon Oct 31:

Beginning "2006 10 1 00:00:00"
Ending "2006 10 31 12:00:00"

--Chris

dh2va wrote:That said, could maybe anybody just zip his spice-working Celestia subdir and I will try this here?

my compiled celestia-version includes SPICE, thats why the executable is so big

oups charge update

ftp://naif.jpl.nasa.gov/pub/naif/MRO/kernels/spk/

START_TIME=2006-10-12T07:35:00.000
STOP_TIME=2006-12-05T16:15:00.000

=> spk_psp_rec00990_00986_01684_p-v1.bsp ( 65Mo )
=> spk_psp_rec00990_00986_01684_p-v1.bsp.lbl


Go Go Go !!!

Well, there seem to be some problems with how Celestia displays spice orbits, but it isn't with the MRO itself.

Here's what I see, using a version of Celestia built from cvs on October 22nd



The MRO (at the right edge of Mars) actually orbits above the surface, despite what the orbit path seems to claim

Here's a CEL URL that should take you to this viewpoint
mro viewpoint

And here's the SSC that I used ( \Addons\spice_mro\spice_mro.ssc )


The naif binary spice file listed in symaski62's post just above this was placed in
\Addons\spice_mro\data\

selden wrote:Well, there seem to be some problems with how Celestia displays spice orbits, but it isn't with the MRO itself.

It's a result of Celestia seriously undersampling the orbit. I need to figure out how to make Celestia choose the number of points to use to draw an orbit. Making a nice rendering of a low planetary orbit over a long timespan requires a *lot* of points.

--Chris

Dea all,
I GOT IT: the ~ typing helped in finding the problem, which was with missing Beginning and Ending timestamps in the SSC file.. now i can plot MRO, but getting the same problem with the undersampled orbit... but it is a big step forward!

Now I am going to modify my files accordingly, so the 3d model from motherlode is displayed correctly.

Thanks again,
Achim

Hello again..
checking now for the MRO orbit, I have to say it is seriously wrong. I guess some transformation of coordinates went nuts..

[img]http://www.physik.unizh.ch/~avollhar/celestia/celestia_mro.jpg[/img]

Disregard MO and MGS orbits.. but according to JPL/NASA, MRO is in an orbit inclined 92.6 deg, meaning passing amost directly over the poles.. which is not the case.

Any ideas?

Cheers,
Achim[/img]

Did you specify the correct reference plane?

I forgot it, so Celestia assumed Mars Equatorial, which is wrong. Presumably it should be Ecliptic.

Hello Selden,
how to specify this? Is there a document how the SSC Files are structured? Sorry for these questions ..

Thanks,
Achim

Specifying the reference plane is a new option in Celestia v1.5. The only documentation available is what Chris has written about it. I've collected his descriptions of the new reference frame features at

http://www.lepp.cornell.edu/~seb/celest ... .html#5.10

Documentation for the older SSC features is availble on the Motherlode on the documentation page at
http://celestiamotherlode.net/catalog/d ... ation.html
.

Hello Selden,
I think I got it now correct.. at least the orbit looks alright.. the only thing left is to find out, if light time delay is in (probably not).. so I will just shift Mars by something like 20 min for its current position to find out if MRO is in front or behind Mars.

Thanks,
Achim