Celestia Forums

Hello,

i like to use Celestia together with current SPICE-data (.BSP /.LBL-files)from http://naif.jpl.nasa.gov/naif for showing up to date positions of spaceprobes.
I read some postings about spice data and using it with Celestia but can`t find a quick ?€?HowTo?€

Sorry: there is no "easy way" to implement SPICE trajectories. You have to assemble them using appropriate kernel data files and specify each of the objects you want to see in an SSC file.

A complete Cassini Spice addon would require hundreds of megabytes. The tables of trajectory information are very large.

Have you tried implementing the Spice trajectory for Pluto?

It is described on the Web page http://en.wikibooks.org/wiki/Celestia/T ... SpiceOrbit

implementing a Spice trajectory for a planetary probe isn't much different. You have to provide a SPICE kernel which includes the trajectories for the objects during the intervals that you want to see.

If you haven't already, please read the Topic at
http://www.celestiaproject.net/forum/viewtopic ... 0724#10724

It includes some information about creating a Cassini Spice addon for a short interval of time in 2005.

Hello,
@ selden: Thank you for your answer. I have needed some time to try the spice-examples you gave in your answer.

I found a posting from ?€?dh2va?€

Your select statement needs to specify the full path to your version of Cassini: "Sol/Saturn/CASSINI", not just "CASSINI". That would explain why it stops working when you delete the xyz trajectory: It's selecting a Cassini that's orbiting around the Sun, not a Cassini that's orbiting around Saturn.

I'd suggest giving the object a completely different name while you're doing the test, maybe "MyCassini" Then there will be no confusion about which object you're looking at. e.g.



Alternatively, you could use the Modify directive to replace parts of Celestia's definition of Cassini by your definition.

e.g.

Hello,

i have now installed the latest Win 1.5pre3 and i can use the unchanged script (i posted above) for Cassini and another one for MRO but not your changed script. (could you please post a complete looking of your changed script?)

MRO has no Modell in Celestia. i started without a MRO addon and without xyz-data.
For MRO i use two files : a small .BSP and .LBL-file from Horizon. I use Start/End time/date i found inside the .LBL-file and place this correctly in the script.

Next and before starting any script i have to tell Celestia a time inside the right time/date range-then i start the script and the MRO-probe appears as a round yellow ball because i havn`t placed any MRO-addon in the model-folder.
When i activate "O" Orbit and i look from a distance to mars all the upcoming next orbits appear (for the whole .LBL-file time) So that result and looking is very good.

Another (the main)problem for many other probes like MEX or DeepImpact,VEX: NAIF offers only (one)the .BSP-file and not the additional .LBL-file. Without the .LBL file a Script do not start.

I have read about the "Toolkit" but i`dont know which part would be useful to generate a suitable .LBL -file. Is that possible....?

How can i build/produce a missing .LBL-file

Thank you again for perhaps a example and support.
regards,Blueriver

I don't know what you mean by "my changed script". I was just suggesting some things you might try. They are not things that I have tried.

I have never created an LBL file. Maybe someone else can help with that.

Sorry.

Dear Selden,
thank you for your answer.

Perhaps there are some special ?€?Spice-doctors?€

here is a link to the spice toolkit in case you haven't got it already. There is a tool called Brief in the kit that will give you all the info you'll need for the bsp files your using. It has a good doc folder that explains the use of tools in the kit.

ftp://naif.jpl.nasa.gov/pub/naif/toolkit/C/

cartrite

Hello,

thank you cartrite for your answer but i think that a separate spice .bsp-file only don`t work. It works only together with an .lbl-file connected with the .bsp content.

In the meantime where i tried out the little script i don`t know how Celestia puts together different xyz-data and spice-.bsp data and some model data?€¦
I`m confused?€¦

Btw. i can see galileo.3ds and huyens.3ds in the Model-folder .but i can`t see a spaceprobe on the screen -the probe is not shown. I don`t know why it is so?

When I go to Mars i can see the the MRO-probe orbit but I can`t see the MarsExpress or the MarsSurveyor orbit?€¦

Maybe that there are some further improvements in the final 1.5 or a kind of celestia-spice-manual showing perhaps a example how the Cassini model included in the 1.5 install is working together with a current Cassini-spice data file from NAIF.

regards,
Blueriver

Blueriver wrote:Hello,

thank you cartrite for your answer but i think that a separate spice .bsp-file only don`t work. It works only together with an .lbl-file connected with the .bsp content.

The simple SPICE kernels that i generated when Chris first added SPICE support to Celestia need only BSP files. No separate LBL files are needed. You can verify this by changing the extension from .LBL to .NOTLBL. The SPICE kernels will still work.

I verified this just now with the SPICE trajectories that I use for testing.
http://www.lepp.cornell.edu/~seb/celest ... 0-test.zip
(1.1MB)
This Addon uses trajectories for Cassini, Earth, Saturn and several of Saturn's moons which all are defined in a single SPICE kernel BSP file.

LBL files are plain text files. LBL files are generated from BSP files using a utility program. The program dumps some of the information records that are inside the BSP files into LBL text files so a human being can read them.

In the meantime where i tried out the little script i don`t know how Celestia puts together different xyz-data and spice-.bsp data and some model data?€¦
I`m confused?€¦

xyz data files and SPICE bsp data files are two entirely different methods of defining trajectories.

If you want to include an object which uses an xyz trajectory, you should not define an SSC object which has the same object name and which uses a Spice kernel.

If you use the same name for both xyz and Spice objects, you will cause much confusion. Celestia won't stop you from doing it, but it won't know which object you mean when you try to select it.

This is why I always use the prefix SPICE_ in the names of the objects that have SPICE trajectories.

If you really want to create an object which has the same name as one that Celestia already defines, then you must edit Celestia's SSC file and delete the object that already uses that name.

(I suspect this is what the people at NASA and ESA do.)

But maybe I've misunderstood what you wrote.
If by "model data" you mean the 3D model file which provides the image of the object., this 3D model is specified in the Mesh statement.

You can use the same 3D Mesh for any number of SSC objects that you want. The name of the Mesh file and the name of the SSC object it is used for have nothing whatsoever to do with one another.

Here is an example of an SSC catalog which uses the same model for three different objects. One happens to use an xyz trajectory. The other uses a Spice trajectory. This is just a simplified example. I'm not including all of the details needed to make it work.


You can even make a planet look like a spacecraft:
(This ssc file is not simplified. It will work as it is to change the appearance of Mars.)

Btw. i can see galileo.3ds and huyens.3ds in the Model-folder .but i can`t see a spaceprobe on the screen -the probe is not shown. I don`t know why it is so?

You have to set Celestia's date to a date when those spaceprobes were in orbit. In other words, you have to set Celestia's date to a date that is after the Beginning date and before the Ending date in the SSC files for those objects. If Celestia's date is set to today's date, you cannot see them. Those spaceprobes are no longer in orbit. Galileo crashed into Jupiter and Huygens landed on Titan. Today's date is after the Ending dates for those objects.

When I go to Mars i can see the the MRO-probe orbit but I can`t see the MarsExpress or the MarsSurveyor orbit?€¦

Which version of Celestia are you running?
Which orbit do you mean?
Do you mean the ShroxMars orbits included in Celestia's CVS archive?
Or do you mean SPICE orbits that you created?
Or did you use SpiceOrbits that someone else created? If so, where did you get them?
I'm sorry, but I really don't feel like guessing. There are too many different mistakes that would cause objects and orbit paths not to be drawn.

Maybe that there are some further improvements in the final 1.5 or a kind of celestia-spice-manual showing perhaps a example how the Cassini model included in the 1.5 install is working together with a current Cassini-spice data file from NAIF.

The only planned improvements that I remember Chris mentioning will be to support the orientation information which is included in some Spice kernels. My understanding is that this improvement won't happen until after Celestia v1.5.0 final is released.

The test Addon I list above (spice-cassini-150-test.zip) can be used with Celestia's model of Cassini if you want. You have to change the definition of Spice_Cassini. Add a Mesh entry and change its Radius entriy.

e.g.

Dear Selden,

thank you for your detailed answer. It is very helpful so I can go on step by step..

I run the spice-casini-150-test script you mentioned and I have looked to the details.
When i use the 050825R_SCPSE_05186_05205.bsp-file i can open it with the ?€?brief?€

I believe you are correct that a BSP file containing the trajectory of only one object can't work with Celestia. It needs to contain a second trajectory that can be used as the "Origin".

I've sometimes seen the same "insufficient ephemeris information" when specifying Beginning and Ending which exactly match the ones in the BSP file. Selecting times that are slightly closer together by just a couple of minutes, within the BSP time interval, seems to work better. Other times the BSP file trajectories are incomplete, with gaps in the middle. Celestia requires the trajectories to be complete between the Beginning and Ending times that you specify. In that case, you can use part of the BSP time interval, but not the entire thing.

Dear Selden,
thank you for your help.

I have made some additional changes in the script which belongs to the start / end times and now the warning message in Celestia (~Insufficient?€¦) doesn`t appear.

When I now set the time in Celestia into a valid time (Beginning "2007 01 02 00:00:00" Ending "2007 01 08 00:00:00") i can see that the script is not working correctly and I don`t know why it is so.

The script is based on the spice-cassini-test-script. It`s also possible to make a object search for lets say spice_mars, spice_mars_bary, spice_mro etc. but the shown positions are not correct.
As example: the shown position for spice_mars is far away from Mars and also the spice_mro is far away from Mars etc and the positions are shown just with the little red triangle marker point (no round globe)

Do you have an idea what could be the problem / perhaps a mistake in the script?

Here again is the script:


When I look again to the spice-cassini-test-script then i can see that all objects which are available in the 050825R_SCPSE_05186_05205.bsp-file are also included in the script. (Btw. the spice_earth is shown complete in green colour. Also the moon, spice_jupiter=blue, spice_Rhea=white, spice_saturn=yellow

When I made the mro-script I don`t make use of all objects available in the spk_psp_rec02125_02028_02125_r-v1.bsp-file. Could this be the problem?
Do I always have to make use of all objects in the script when they are in the .bsp-file and in special is the sequence of the objects also important in the script? (first spice_SSB, second spice_mars_bary?€¦.

You mentioned:
>It needs to contain a second trajectory that can be used as the "Origin".

So I think a spice-script can also work only with two Objects (spice_mro and spice_ssb) and then it should work!?
Then this script should also work:


?€¦.but the same: I can find the positions of the (four) spice_objects with >Goto but they are shown far far away (no globe/only red triangle marker). I don`t know why it is so because the spice-cassini-test-script / .bsp-file works correctly.

Thank you again for your help and further suggestions.
regards,
Blueriver

You only need to use the Spice orbits for the objects you want to display. You do not have to use all of them.

The order is important: you must define the orbit of the "origin" before you can define the orbit of the 'target".

Usually objects are not drawn and their markers are at the wong places if Celestia is set to the wrong date. You must set Celestia's time to be after May 8 but before May 14. If Celestia is set to today's date, the objects would be shown at the last [x,y,z] location specified in the Spice kernel, which is not where they would be today. They can't move away from that location because there is no information.

Use Celestia's menu Time/Set Time... to set Celestia's date to 9 May 2007

Exactly what bsp file are you using?
Where did you get it?

I found the MRO bsp file on the NAIF site.

Your MRO SSC file works fine for me when I set Celestia to May 9. I can see the spheres which indicate the various bodies and the MRO itself. The location of Celestia's Mars is only slightly different from the location of Spice_Mars.

Note that Celestia does not draw the MRO orbit path correctly. It uses samples that are too far apart and the orbit changes too rapidly.

Dear Selden,
thank you that you have made a test on your system with the same .bsp-file.

i just have made a test again- set the date correctly but my MRO SSC file won??t work on Version 1.5pre3 (german language). i only get positions far far away from mars. see this picture after i say "Goto"

and this is when i scroll back to a more far point from spice_mro (you can see that then Mars is comming closer to the position

but
then i test it with the 1.50pre1 and a wonder: there it works! i can Goto the four spice objects, can see the spheres which indicates the various bodies....in1.50pre1 it`s ok.

Then i tried to start my other SSC (spk_psp_rec02125_02028_02125_r-v1.bsp-file / i load this file from NAIF in January) but these script doesn`t work in both versions. It is not working in 1.50pre1 and 1.50pre3

Perhaps i have a mistake in the script?

Btw. is it important how many under-folders i place in Celestia/extras/
..there are now an folder with the cassini-test-script, the mro-short script, the mro-long script....

It`s a bit mystic why the short MRO-ssc work in 1.50pre1 but not in 1.50pre3 and why the long MRO-SSC is not working in both versions.

Thank you for your answer and support again.
regards,
Blueriver

Blueriver,

No, it doesn't matter how many subdirectories you have in /extras/

I did my test with the U.S. English version of v1.5.0pre3
I do not know why yours does not work.

Please double check to make sure you are using exactly the same SSC catalog and data files. Also, check to make sure you are using the original version of pre3. with no changes to nearstars.ssc, for example. That file determines where the Sun is located.

Here is how Spice_MRO looks on my system using
spk_psp_rec03736_03648_03736_r-v1.bsp

For this picture I made some minor changes: I set the radius of Spice_Mars to be the same as that of Mars and colored it yellow so you can see how close they are together.
I also made the MRO a colored sphere and set its radius to be 100 so you can see it and its shadow on Spice_Mars.

Other than these changes, I used exactly the same SSC Catalog as you posted above.

(Note that these are catalogs, not scripts. Catalogs tell Celestia where things are. Scripts change what Celstia does while Celestia is running.)


.

Dear Selden,

i like to download a U.S.. English Version 1.5.0pre3
I get my 1.5.0pre3 i use yet from here : http://www.shatters.net/~claurel/celestia/files/ >celestia-win32-1.5.0pre3.exe

Is that version the correct?

I have made no changes for myself on the .ssc-files in Celestia/data
Here is a picture of the /data folder content:


regards,
Blueriver

Blueriver,

Yes, that is the correct URL for pre3.

Dear Selden,

i just install the 1.5.0pre3 again but it`s the same: no success

i now download the 1.5.0pre2 . maybe the script works there .

Could it be possible please, that you could post the script again (with the minor changes to radius and colours? That would be very good...

I tell you tomorrow about 1.5.0pre2 test.

regards,
Blueriver