Celestia Forums

Dear all,

Not sure where the best place to post this is but I'll add it here and feel free to move it. I'm working on Mars Express and we're about to launch a website for the public to view the results from a small 640x480 camera on the spacecraft that we've been operating for a year now. The website will launch on the 22nd August and we want to invite the public to look at the images but also work with them - analyse them, spot features etc.

One of the big things we need to provide to help people is an idea of where the pictures were taken. To do this we wanted to put the orbit of Mars Express on the website so people could download the orbit into Celestia and then look at the planet from the point of view of the spacecraft. I can produce an xyz file of the orbit (the Mars Express orbit is a little complex, so sampledorbit would be best). I can probably write a simple cel file for each observation too that can go to the right time, 'sit' on Mars Express and look at the planet. My problem is what ssc file to use? I think I will create one with a default model but if anyone has a model that could be used - or any suggestions on this please let me know (although be aware you would have to give it to us free of charge) and we can put that on the website instead. The timescale is important though - we launch the site next week - so let me know as soon as possible.

Thank you in advance!!

ormstont wrote:...but if anyone has a model that could be used - or any suggestions on this please let me know (although be aware you would have to give it to us free of charge) and we can put that on the website instead...

Do you really want us to believe that ESA don't have a descent model??

ElChristou wrote:

ormstont wrote:...but if anyone has a model that could be used - or any suggestions on this please let me know (although be aware you would have to give it to us free of charge) and we can put that on the website instead...

Do you really want us to believe that ESA don't have a descent model??

Got one, here: http://www.esa.int/esa-mmg/mmg.pl?b=b&type=A&subtype=3D%20Model&single=y&start=4

BTW, just saw that on your site there is plenty of animations that use Celestia; no one will ever credit the hard work??

We do indeed have models of Mars Express but they're not ones that easily or quickly translate into Celestia, hence was looking for an existing add-on that we could add for download on our site.

I cannot and do not speak for the whole agency, but where I publish work using Celestia I do credit it to Celestia. I was hoping that by providing Celestia downloadables on this new part of our website we would strengthen our already productive relationship with the Celestia software and community. However, it does not need to be added, we can remove that part completely and seek another solution if that's the opinion of the forum.

Don't know if it helps or not, but you can find a model of the Mars Express HERE on the Celestia Motherlode.
Thanks for this information, too. Should be very interesting to view.

Take care, Brain-Dead Bob

EDIT: Would be nice if you people could credit the author, Mr. Jack Higgins, if you decide to use this model though.

ormstont wrote:We do indeed have models of Mars Express but they're not ones that easily or quickly translate into Celestia, hence was looking for an existing add-on that we could add for download on our site...

As I work on models here, I'd like to talk about this.
What's make me really sick (and I don't want here to be disrespectful or something, it's just a fact and you will see why) is that you guys from ESA or NASA do have PLENTY of models of every single missions and most of them will end archived (I hope) far, but really far from public.
Why this make me sick: when we poor guys (with a job, with a life etc...) want to do something for the community (and in our case for who is interested on this planet) by providing a detailed model of a spacecraft or the reconstitution of a mission, not only we need to invest a bunch of time for the effective work on modeling for example, but ALSO we will have to lose many, but many, but MANY hours to find a ton of docs, sort out things, discuss about details, compare, analyze etc... this to be able to rebuild the model from zero.
Now the problem is that despite all the time and talent of the word, if you don't find the docs, you won't be able to do anything and even if you achieve something descent, you are not 100% sure of the accuracy of your model.

Now, from my very selfish point of view, I think you can understand why I'm sick to know that there is somewhere PERFECT (in the sense of totally correct from CAD point of view) models that COULD be used within a soft like Celestia for the education/pleasure of the public... but nope, totally unqualified fools have to redo the job...

So, I'm a bit sorry to react this way, but when you came here (caution, despite my post you are really welcome! ) and ask for a model free of charge (of course!)... you can imagine...

Anyway, this said, I suppose your project of using Celestia can be interesting; now, as far as I know, do the resolution of maps available for Mars are enough for what you want to do?

Thanks for the positive responses so far. For the model I have seen that one on the Celestia Motherlode, of course we would credit Jack Higgins, but we would also need to get in touch with him for his permission (one of the reasons for my post).

For the map resolution, the standard Celestia textures (or more importantly the location names) should be sufficient, although we may add a link to the Celestia Motherlode so people can download higher resolution textures if they wish.

Finally, further to my request for help about the model, I would value anyone with experience of cel files to give me a hand with a simple template that we could use to 'zoom' to each observation, I'll try and post what I've got tomorrow and might need to ask for some help with that. Also - how would you think the best way to post orbit files on our website...one xyz for the whole mission would be too large so we might have to break it into separate files (monthly for example) but how to integrate these into one model? Any ideas would be much appreciated!!

Thanks again!

ormstont wrote:Thanks for the positive responses so far. For the model I have seen that one on the Celestia Motherlode, of course we would credit Jack Higgins, but we would also need to get in touch with him for his permission (one of the reasons for my post).

That may be difficult as Jack has not been around in some time.
However, let me make a broad general statement here. In those cases where a license has not been explicitly referenced on the web site,
you can generally assume that the models are free to use, so long as credit is given to the author. Also, they are generally expected to be
used for non-commercial purposes.

If this is not satisfactory, you can try to contact Jack via the e-mail address listed on his Celestia Home Page which is HERE.
Hope this helps...

As an aside to the proprietor of the Motherlode...
Ulrich? Do you have any other helpful comments for this gentleman?

I'm in a hurry and I will be off line for the rest of the day.
So just a brief response here.
I also can only suggest to try Jack's email adress on his website.

@ ormstont:
Thomas,
I'm sure that our spacecraft specialists here (like ElChristou or Runar, just to
mention two of them) would be able to build a new model if they would have more
accurate information (from ESA?) and a little bit more time.
Bob or me would be able to write a cel-script and so on.

But all this will need some more time than just a few days. So I would suggest
to add the Celestia MaresExpress add-on section later on to ESA's website.

Adirondack (Ulrich)

Thanks again for the responses - I know this is a bit last minute but it suddenly struck me that it would be great to get some Celestia involvement (as I've always loved the software and would like it to have a bigger part on the ESA website). I think actually that a launch site with later updates from the community later could work quite well.

For the concept - I'll probably produce a basic SSC with Mars Express as a dot/sphere (not the prettiest but sufficient for the purpose). Then I'll do basic CEL scripts for each observation. When the site launches one of the big things we want is user participation, so if Celestia users propose updates to the Celestia parts then we can add those and credit you accordingly. I'll post what I've got ahead of time though, hopefully in the next couple of days.

For the Mars Express model - I have found a more detailed Mars Express model deep in the archived Mars Express data but don't know where this came from (may even have come from the Celestia community long in the past). Of course we can't publish this in case it is someone else's work. Maybe it could serve as a base for an add-on developer, would love to provide you the detailed designs of the spacecraft to work on. The problem here is that many of the designs are restricted for commercial confidence (the companies who designed the spacecraft don't want their designs shared with their competitors) so would have to look into whether we can go around this somehow first - I do sympathise though!

Adirondack wrote:...I'm sure that our spacecraft specialists here (like ElChristou or Runar, just to
mention two of them) would be able to build a new model if they would have more
accurate information (from ESA?) and a little bit more time...

Perso, I can adapt a model in dxf for example quite quickly. Now, building a new one from drawings and photos is another story...

ormstont wrote:...For the Mars Express model - I have found a more detailed Mars Express model deep in the archived Mars Express data but don't know where this came from (may even have come from the Celestia community long in the past). Of course we can't publish this in case it is someone else's work. Maybe it could serve as a base for an add-on developer, would love to provide you the detailed designs of the spacecraft to work on. The problem here is that many of the designs are restricted for commercial confidence (the companies who designed the spacecraft don't want their designs shared with their competitors) so would have to look into whether we can go around this somehow first - I do sympathise though!

Don't forget the Celestia models need to be not too complex to keep it usable on a medium config. A typical model in Celestia will only show all the visible part and of course I'm not a specialist but I doubt the sensible parts are visible... If this is the case, we can always do a simplification to keep the global visual info without showing what can be problematic...

Ok, I've got the basics ready, which is really a very very simple ssc that places a small white sphere in the position of Mars Express, deriving the position from a large (~4.7 Mb) xyz that has the positions of Mars Express listed every 10 minutes for 2007 and 2008. Unfortunately this is too big to post directly on the forum here (zipped it's around 2 Mb) but would value people taking a look and checking it works as expected. PM me with your e-mail address if you'd like it and I'll send it over.

Next step...the CEL file!

How much precision are you specifying in the xyz file?
Single precision or double precision?

If single precision is adequate (i.e. if SampledOrbit is adequate), the file could be half the size of what is required if you use double precision.

For more information, see http://en.wikibooks.org/wiki/Celestia/T ... Trajectory

ormstont wrote:Thanks again for the responses - I know this is a bit last minute but it suddenly struck me that it would be great to get some Celestia involvement (as I've always loved the software and would like it to have a bigger part on the ESA website). I think actually that a launch site with later updates from the community later could work quite well.

For the concept - I'll probably produce a basic SSC with Mars Express as a dot/sphere (not the prettiest but sufficient for the purpose). Then I'll do basic CEL scripts for each observation. When the site launches one of the big things we want is user participation, so if Celestia users propose updates to the Celestia parts then we can add those and credit you accordingly. I'll post what I've got ahead of time though, hopefully in the next couple of days.

For the Mars Express model - I have found a more detailed Mars Express model deep in the archived Mars Express data but don't know where this came from (may even have come from the Celestia community long in the past). Of course we can't publish this in case it is someone else's work. Maybe it could serve as a base for an add-on developer, would love to provide you the detailed designs of the spacecraft to work on. The problem here is that many of the designs are restricted for commercial confidence (the companies who designed the spacecraft don't want their designs shared with their competitors) so would have to look into whether we can go around this somehow first - I do sympathise though!

You could ask for editing the plans so that they only show the outside of the spacecraft. In this way there isn't much the concurrence hasn't seen already.
And try to get free play on the plans to come.
I mean that ESA holds all the rights for the plans instead of the company that designed it.

ormstont wrote:Ok, I've got the basics ready, which is really a very very simple ssc that places a small white sphere in the position of Mars Express, deriving the position from a large (~4.7 Mb) xyz that has the positions of Mars Express listed every 10 minutes for 2007 and 2008. Unfortunately this is too big to post directly on the forum here (zipped it's around 2 Mb) but would value people taking a look and checking it works as expected. PM me with your e-mail address if you'd like it and I'll send it over.

Next step...the CEL file!

Upload it to the motherload.

duds26 wrote: Upload it to the motherload.

Unfortunately, that won't do anyone much good at the moment. Ulrich is extremely busy with his own commitments
to work these days, and it will take quite a while to get anything new tested and listed on the catalog. Just FYI...

I'm aiming to get the minimum downloadables to at least see where each image was captured. Therefore while we might make a Mars Express SSC available, ideally I'd like to do without it.

My question then is this: I know that it's possible to set an observer position in a celx script but how to I specify what frame and what units to set this in? I've tried to get the Mars Express position but the numbers are nowhere near the same as what was specified in the xyz file which were km in the EquatorJ2000 reference frame Sol/Mars. What is the conversion to apply here? Thanks in advance!

Hi,
very good idea to have Celestia involved on ESA (and NASA?) Mission websites!
It would be a dream to have a first class visualization for the masses – and to have a kind of -Howto- for the maybe not so skilled user to load the needed data into Celestia.

Do you think about to make use of JPL SPICE Kernel files instead of XYZ-Data? There is a posting from last year:
http://www.shatters.net/forum/viewtopic.php?f=2&t=11059&st=0&sk=t&sd=a&hilit=spice&start=15

My personal favorite would be also -of course- to set a observer location on earth because i like to know also when/if Mars Express is probably just behind Mars (in the dark zone)
It would be also interesting to watch the orbits.

@ ormstront: would it be possible to think about to implement a visualization website also for the Venus-Express probe / orbit in the future

Blueriver

Blueriver,

Don't forget that SPICE trajectories usually are *much* larger than xyz trajectories and more difficult to configure in Celestia. Of course, they're what you should use when accuracy is most important.