Jack's Galileo xyz

[Paul L]

I'm in the process of building some scripts using Jack's excellent set of space craft trajectories. I've noticed that the Galileo probe (in my simulation) has some inaccuracies with respect to the Venus encounter and the initial Jupiter encounter (most notably is the fact that it passes through the planet). Now, am I just missing an update / fix - or (and I hope Jack is reading) is there in fact one or two errors in this file ? For the record, the Voyager xyz's work perfectly - so I'm kinda hoping I'm just missing an update or something in the case of Galileo.

[JackHiggins]

Um... Well yeah it's not eactly the most accurate trajectory to be honest... There are so many flybys though (around 40 just around jupiter) that I was going to wait until after the Galileo mission ends this september, and then come out with a HUGE Galileo xyz, with all the flybys in their full detail. Horizons has no way to control the number of xyz points based on proximity to other objects, so you have to just increase the level for each flyby...

On the same point, the current xyz does have some real innacuracies, because the craft's trajectory has changed slightly in the last few months. It's actually a bit closer to Jupiter now than my (or anyone else's) xyz's show, and when I last checked Horizons, they actually show Galileo crash.

It's better to wait until it's all over though, to get the full thing accurately, instead of waiting for different predications.

Sorry I can't be of much help, but i'm not going to spend hours doing a trajectory that's subject to change without notice...

[Paul L]

Much appreciated - and your reply makes sense. When it's all over, I suggest you start with the Venus fly by. My poor old Galileo space craft doesn't make it beyond venus (rather unceremoniously crashes through the planet).

Love your work.

Paul L.

PS - How do I 'see' cassini with just the .ssc and model ? Do I need to 'borrow' an .xyz from another object ?

[JackHiggins]

I thought somebody had made a cassini xyz...? You might find a makeshift ssc file on selden's site somewhere http://www.lepp.cornell.edu/~seb/celestia/index.html or maybe an xyz I haven't checked...

If there isn't any i'll put up a link to the one I have made for myself. It's pretty basic (frequent crashes through staurn & titan) but it will show it up. You do need an xyz to show the craft, if the ssc file refers to an xyz-style orbit.

PS. currently Horizons doesn't show an accurate cassini orbit; the trajectory has changed to fix possible problems with the huygens entry into titan's atmosphere, but horizons doesn't show this yet.

[Darkmiss]

I have a cassini XYZ file i collected a while back
Im not sure who made it, I think it may have been Selden

Ill post it to you if you wish Jack, so you can place it on your web site.

[JackHiggins]

Darkmiss, I'll put up my cassini xyz (slightly better than the average... ) in a minute- must restart windows first!

[insanity]AHHH NOT ANOTHER SCREWUP!!!!![/insanity]

//added after insane rage

Oh, um... i meant to say- thanks for the offer but don't bother- i have my own so no need to send yours on! thanks anyway!

[JackHiggins]

Well here we go... http://homepage.eircom.net/~jackhiggins ... inixyz.zip

It's just the xyz & ssc nothing else.

Just like galileo, i'll wait till the cassini mission is over to make a full xyz!













NAH just messing!! (No way would i wait until 2008 just for that...) I'll make one once horizons update their trajectory!