Feedback needed Re: HUGE Galileo xyz

JackHiggins · Post #1by **JackHiggins** » 02.11.2003, 14:31

Hey all

It's partially finished! Very partially...

The HUGE galileo xyz, in case you don't know about it already, is my attempt to make a trajectory for the full galileo mission, with detail of as high as 1 point per minute (real time) during close flybys of planets and moons during the mission.

So far, I have the entire mission with a basic set of 12,000 points. (One point every 10 hours.) This is more than accurate for interplanetary travel & cruise portions of the mission.

Then, for times when I need better detail, I've got many more points.
Details of high resolution portions so far...

Launch - 01/nov/89 - 3000 points (leaving earth, going into heliocentric orbit)
01/feb/90 - 21/feb/90 - 1000 points (10 days before and after Venus gravity assist)
05/feb/90 - 16/feb/90 - 3000 points (very highres [5 min samples] for 5 days before and after the Venus gravity assist)
01/dec/90 - 18/dec/90 - 1000 points (9 days before and after the earth-1 gravity assist.)
07/dec/90 - 10/dec/90 - 4000 points (Portion of earth-1 flyby when Galileo was within the moon's orbit. Required because of Galileo's very close approach to the earth, which I have actually never seen before in 3d!)

You can download this partially completed part of the xyz from...
http://homepage.eircom.net/~jackcelesti ... _beta1.zip (LINK NO LONGER WORKS - SEE BELOW) It's only a zipped xyz file however, the required ssc is here:

Code: Select all

"Galileo HIGH DETAIL xyz" "Sol"
{
   Class "spacecraft"
   Mesh "galileo.3ds"
   Radius   0.01

   InfoURL "http://galileo.jpl.nasa.gov"

   Beginning 2447818.565972222  
   Ending    2452912.871527778

   SampledOrbit "galileo_highdetail.xyz"

   RotationPeriod    1.0e9  # Essentially no rotation . . .
   Orientation     [ 90 0 1 0 ]

   Albedo         0.50
}

Please give me your feedback about whether it's detailed enough, too detailed, etc etc.

It will probably take me a good while to get it finished, but it will be the largest xyz file ever made also...

TERRIER · Post #2by **TERRIER** » 02.11.2003, 21:49

Jack

Great work as always.
I would say that your level of detail is just fine, although I don't know if we'd notice too much if you left out some of the high res points to the xyz!

Just wondering what the file size is likely to be when it's complete?

In the early part of the mission I kept a lock on Earth, and it was pretty cool how Venus suddenly appeared during the February 1990 gravity assist.

I notice that in this partial mission it actually runs until 30th September 2003, and I assume you have not included any detailed mission points after December 1990. I'm just wondering what data you've used for the latter part of the mission? because I decided to run it through to it's completion, and boy were there some spectacular encouners with Jupiters moons from 1996 onwards!

Also when you complete the entire mission, will you be including the different models of galileo as you have done with your other complete Galileo xyz, ie 'with dish closed', 'with dish partially open', 'with probe' and 'without probe'?

Cheers and keep up the good work, I hope we see the next phase, or the completed mission soon!
TERRIER

JackHiggins · Post #3by **JackHiggins** » 02.11.2003, 22:50

TERRIER wrote:I would say that your level of detail is just fine, although I don't know if we'd notice too much if you left out some of the high res points to the xyz!

I suppose I probably could, but why not go the whole way when there's effectively no limit to the possible file size?!*

Just wondering what the file size is likely to be when it's complete?

I would guess somewhere in the region of 7-9MB, although it could be a fair bit more, depending on how things go!

In the early part of the mission I kept a lock on Earth, and it was pretty cool how Venus suddenly appeared during the February 1990 gravity assist.

Shows you how quickly those flybys happen relative to the length of time spent in cruise mode...! Even more fun to watch is the Earth-1 flyby, locked to earth - i'm not aware of any xyz before now that actually showed Galileo go around the proper side of the earth! (Same goes for the Earth-2 gravity assist, although I haven't done that bit yet)

I notice that in this partial mission it actually runs until 30th September 2003, and I assume you have not included any detailed mission points after December 1990. I'm just wondering what data you've used for the latter part of the mission? because I decided to run it through to it's completion, and boy were there some spectacular encouners with Jupiters moons from 1996 onwards!

What I did was make a base xyz, with 12,000 points, for the whole length of the mission. (Actually it was 3 sections of 4000, since that's the Horizons output limit) There was no way of controlling when each point would come out, so those well-rendered flybys are just random coincidences really!

In case you're interested, the way i'm putting the whole thing together is...

Download each xyz section through the Horizons FTP method
Convert each file to celestia-type xyz through an M$ Excel spreadsheet
Paste the converted section into a temporary wordpad file
Make a backup copy of the full galileo xyz file, and then paste the new section into the original.
Save and close, then re-open and past the WHOLE file into a blank M$ Excel spreadsheet again.
Do an A-Z sort, to merge the two sections into one, in order of the Julian dates. (Won't work properly if they're in the wrong order)
Paste it all back into the original xyz file, save, close, test out.
If it works, i'll delete the backup, and keep the new improved file as the xyz.

It sounds a LOT longer and more complicated than it really is!

Also when you complete the entire mission, will you be including the different models of galileo as you have done with your other complete Galileo xyz, ie 'with dish closed', 'with dish partially open', 'with probe' and 'without probe'?

That's just an ssc issue, and my existing ssc to show that should show the "animation" properly. It'll take so long to upload the xyz on it's own, I won't make a whole package of it, i'll just have the xyz and maybe the ssc on their own inside the zip file. I might even have a spanned zip so I can put up each part individually!

I've got to contact eircom too, to get them to upgrade /~jackcelestia/ to 50MB size- you're supposed to get that when you sign up for flatrate (which I got recently) or broadband/DSL.

The next section will probably run up to and including the Ida flyby, and then i'll start work on the probe release, orbital entry, moon flybys etc!

*Ok, so there is a limit in how much I can actually fit into my website, but i'm not going to break 20 or 50MB!!

JackHiggins · Post #4by **JackHiggins** » 07.11.2003, 20:58

Stage two complete!

Get it from here: http://homepage.eircom.net/~jackcelesti ... _beta2.zip (LINK NO LONGER WORKS - SEE BELOW) (1.07MB, and the above link no longer works)

As well as the previously mentioned hi-res sections, this one also contains...

19/oct/91 - 09/nov/91 - 1000 points (10 days before & after gaspra flyby)
26/oct/91 - 03/nov/91 - 3000 points (gaspra flyby)
29/nov/92 - 19/dec/92 - 2000 (10 days before & after the Earth-2 gravity assist)
07/dec/92 - 10/dec/92 - 4000 (very hi-res [1.5 minutes or so samples] for the closest portion of the Earth-2 gravity assist.)
18/aug/93 - 08/sep/93 - 3000 (Ida flyby- no super hires portion needed since galileo was pretty much travelling in a straight line at the time of the flyby, and didn't really need more than the accuracy I have here)

Check it out!

Use the above ssc file still as well!

Also I've decided that as well as the xyz trajectory, I will do a completely new Galileo Probe xyz trajectory, showing the plunge into Jupiter's atmosphere. The Galileo and Galileo Probe xyz's will also be synchronised when they are in close proximity, so that you don't get that horrible jumpy effect that you see now! AND, I will make a few extra galileo models showing the deployment of the RTG and magnetometer booms, and possibly seperation of the IUS. (I'm not sure whether this actually happened in the timeframe of the xyz or not though)

JackHiggins · Post #5by **JackHiggins** » 07.11.2003, 22:53

Ok, I need help...

I'm looking for the dates & times when Galileo's RTG and Magnetometer booms were deployed, but I can't seem to find any info on this ANYWHERE on the net!

Clearly it was after the IUS burn, but I really need to know is whether it was during or before the timeframe of the xyz file... Then I can simulate this with a couple of new models also.

If anyone knows where online I can get this information, i'd be very grateful thanks!!

JackHiggins · Post #6by **JackHiggins** » 09.11.2003, 13:34

Hm... So does anyone know about the boom extension times?

Anyway... In the meantime i've continued working on getting the hi-res samples for all the close flybys etc, while in Jupiter orbit. (I'll leave the probe release section until the end!)

What i've decided to do is sample 4000 points, over the usually 6 days per orbit when Galileo is within Callisto's orbit. This gives a minimum sample rate of 1 every 2 minutes 10 seconds, and a maximum (for the final plunge) of a point every 1 minute 5 seconds.

I'm having problems when I tried to get even higher res data (less than 1point/min rate- Galileo started to get really jerky & not move smoothly at ALL. However, even for the very closest flybys of a few 100 km, the 2min10 sample rate seems to show everything very well, so if I can't fix the super-hires samples, I won't bother & i'll just leave them out.

On one occasion so far (i've got the first 9 orbits done) Galileo has gone through Europa during a flyby. I've checked the xyz data, and it seems as if this is a problem with the VSOP87 orbital info for Jupiter & Europa, not with my trajectory... (It's inside Europa for around 7 minutes, so it can't be the sample rate not being high enough)

It looks like the file size (download) will be around or under 5MB after all. I always wildly overestimate at the start (see above :roll:

) so that I won't be surprised at the end by a huge download... It's not intentional!!

TERRIER · Post #7by **TERRIER** » 09.11.2003, 18:14

Hello Jack

I don't know if this may be helpful, but it is an excerpt from a report regarding the Galileo magnetometer I found in GIF image format, that I've printed, scanned and re-read using 'ABBYY Finereader'.

The Galileo Magnetometer: First Results from the Solar Wind and the Flyby of Venus
M. G. Kivelson (Inst. of Geophysics and Planetary Physics and Department of Earth and Space Sciences. UCLA, Los Angeles, CA 90024-1567)
The Galileo Magnetometer has been collecting data since October 19, 1989, when it was turned on prior to the separation of the upper stage booster while the spacecraft was still in the terrestrial magnetosphere. Ths first solar wind data, from October 21, 1989, were obtained as a coronal mass ejection from a flare on October 19, 1990 passed 1 AU. Extremely strong forward and reverse shocks were observed as the disturbed solar wind flowed by the spacecraft. Nearly continuous data in the solar wind, at time resolutions ranging from approximately four samples per second to one (averaged) sample every eight hours, have been obtained for the first year of operation, the data rate changing as bit rates available for commnmcations have varied.

I'm not sure whether the date quoted for the coronal mass ejection should be October, 19, 1989 instead of 1990, but that's beside the point!

Cheers,
TERRIER

JackHiggins · Post #8by **JackHiggins** » 09.11.2003, 21:35

That's great - at least now I know they were deployed on the 1st day of the xyz (Oct 19th '89) - do you have a link for where you got that gif file?

What I need now are the actual times when IUS seperation & boom deployment occurred. I want it to be really realistic... If I can't find the info online, I'll email someone at JPL to see if they can give me any details.

In relation to the xyz progress...
I've got high-res data for the first 27 perijoves (term?) now, so i've only got another 9 to go before the end of the mission. Unfortunately i've discovered several more errors in the positions of the Galilean moons, resulting in 2 crashes through Callisto (almost right through the center both times) and one through Io also.

For some reason the jerkyness is back again too a few times, but I have no idea why it's happening with the 2min10 sample rate... When I have the full 39 perijoves (again, term?!) done, i'll post the xyz for further evaluation, and see if anyone else can figure out why it's happening...

Post #9by **selden** » 09.11.2003, 22:10

One page with detailed timings for STS-34, including the IUS separation, is at http://members.aol.com/WSNTWOYOU/STS31MR.HTM

TERRIER · Post #10by **TERRIER** » 10.11.2003, 03:20

Jack
I've managed to find the link to the UCLA report where I got the excerpt from, plus several others regarding the magnetometers. I don't think they'll be much help to you though.
http://www.igpp.ucla.edu/galileo/publications.htm

On the plus side, Ive managed to find another link regarding the IUS stages;
http://photojournal.jpl.nasa.gov/catalog/PIA00727

I would hazard a guess that the booms were deployed as soon as the final seperation from the IUS was complete and the craft entered it's VEEGA trajectory at 21:05 EDT, 18th October 1989 :?:

Lastly, I know this will not help with your SSC, but I've found what I thought was an interesting site relating to the company that produces many of NASA's retractable booms / solar arrays etc. Here's the link;
http://www.aec-able.com/Booms/coilboom.html

regards
TERRIER

JackHiggins · Post #11by **JackHiggins** » 10.11.2003, 23:53

selden, TERRIER

Thanks for the links- those are exactly the kinds of things I've been looking for!

(I wonder why google couldn't get them for me!?)

I've seen that site with all the booms & panels once before- I would have thought that nasa would have a laboratory of their own to make relatively small items like the booms at least, if not the panels...

(And actually it will help- i'll be able to find out which type of the booms galileo was using, and how they looked while unfolding!)

JackHiggins · Post #12by **JackHiggins** » 15.11.2003, 21:45

Stage three complete!!

Download from... http://homepage.eircom.net/~jackcelesti ... _beta3.zip (3.64MB)

(The ssc above is still what you need to use to view it)

Here's the list of all 36 Hi-res sections (all have 4000 points):

Some of the above are actually higher res than others, because the 4000 points are over a shorter time period. This applies to the last few orbits only though. These are the only sections of data within the xyz file- between these the spacecraft just travels in straight lines. I'll merge this data with the full xyz files I posted previously after I get the data section for the Probe deployment!

The crashes through the moons that i've mentioned previously are:

Europa - 20/feb/97
Callisto - 17/sep/97
Europa - 16/dec/97
Callisto - 05/may/99
Callisto - 14/aug/99
Io - 11/oct/99
Io - 22/feb/00

I find the best way to view the whole thing is like so...
1. Set the time back to 1995, and go to galileo.
2. Split the screen in 4 (Ctrl + R and then Ctrl + U on each new frame)
3. On each frame, set galileo locked to one of the galilean moons, and track it also. Then move galileo out of the field of view (right mouse drag) to speed up the frame rate (it speeds up a LOT when not rendering the galileo mesh 4 times over!)
4. Speed up time, and enjoy!

(Oh I also find that setting ambient light to a tad above 50% makes the moons look much better!)

//edited to correct figures

JackHiggins · Post #13by **JackHiggins** » 19.11.2003, 23:28

I contacted eircom today about getting the site upgraded to 50MB size. (That's what you're supposed to get when you sign up for flatrate) Apparently their system screwed up, and it was supposed to have happened automatically about 6 weeks ago... Anyway when I get the extra space, i'll put up the Galileo xyz ASAP. (I have it finished now!)

JackHiggins · Post #14by **JackHiggins** » 27.11.2003, 00:07

Still no change with the 50MB situation, but apparently it should be fixed soon.

Anyway, i've posted a spinoff of this project, a new xyz for the Galileo atmospheric probe. Download the xyz from #5 on the Spacecraft page of http://homepage.eircom.net/~jackcelestia/ , details here http://63.224.48.65/forum/viewtopic.php?p=26743#26743

bh · Post #15by bh » 27.11.2003, 01:16

Jack...if webspace is an issue for you I can let you have some of mine. I've a share of 500megs at berasan.com. They really like this stuff BTW.

Still waiting to mirror Orion's ISS and new Soyuz model (It looks great!)....but no contact thus far.

mmm....to be continued...

Regards..bh.

Post #16by **chris** » 27.11.2003, 02:51

Jack,

I think that the errors in the positions of the moons are actually due to errors in the position of Jupiter, to which the moon positions are referenced. The VSOP87 orbits for the planets should be accurate to within an arcsecond, but this isn't accurate enough to simulate spacecraft flybys . . . One arcsecond as seen from Earth is (very roughly) 3000km in the neighborhood of Jupiter. The solution is for Celestia to use the more accurate JPL ephemerides for the planets. The disadvantage of the JPL ephemerides is that the data set is very large if you want to cover a time space of several millenia (as the VSOP87 orbits do.)

You may want to try using Horizons to create an XYZ for Jupiter and see how this affects the Galilean satellite flybys. If it corrects them, then it proves that the major inaccuracies are with the orbit of Jupiter rather than the satellite orbits.

--Chris

JackHiggins · Post #17by **JackHiggins** » 27.11.2003, 22:34

bh wrote:Jack...if webspace is an issue for you I can let you have some of mine.

Thanks for the offer, but it's not actual webspace that's the issue- i'm just not going to give in to Eircom (evil empire that they are)- I want my 50MB!!

I'm paying for it myself like, so I should get it...

Chris,

Yeah that's what i'll do- i'll make a patch for solarsys.ssc which has a beginning & ending xyz section for jupiter, and put that up whenever I get the 50 megs too.

MB · Post #18by MB » 28.11.2003, 10:12

Jack,
I am working on a detailed .cel script on the Galileo trip using your 3... Meg xyz trajectory. Even with the new cel script tools provided by Christophe, It is a rather long work, THerefore I would kike to know if this version of the xyz is the definite one or do you plan some update?
Thanks
MB

JackHiggins · Post #19by **JackHiggins** » 28.11.2003, 21:34

I don't anticipate any more updates, unless Horizons themselves have made some errors that I'll need to correct (which is highly unlikely).

(Obviously apart from the final full release like!)

Sounds like a great idea though- can't wait to see it!

JackHiggins · Post #20by **JackHiggins** » 29.11.2003, 17:08

Great...

Looks like Callisto's orbit is off too... After getting an xyz for jupiter with 1 point every 5 hours, The only 4 crashes remaining are:

Callisto - 17/09/97
Callisto - 05/05/99
Callisto - 30/06/99
Callisto - 14/08/99

And the one on 30/06/99 never happened before, the improved orbit for Jupiter actually caused it!! They're all pretty bad, with Galileo going well inside the moon each time.

All the other ones look fine, apart from one flyby of Europa at an altitude of ~40km. That seems a bit too close to be realistic...?

I could do an xyz for Callisto at the time of each flyby... What does everyone else think?

// spelling