Celestia Forums

Hi there,

I am new to Celestia, and I was wondering if someone could tell me if there is an add-on to do the following:

Is there any possibility of plotting spacecraft courses accurately and displaying them as well as their various parameters in Celesia?

What I would like to be able to do is use the software to compare different propulsion types, say for a trip from Earth to Europa, for example. Plug in start point and destination, and a bunch of spacecraft parameters (mass, thrust, acceleration, and the like) and see how long it takes to get there, what the course plot looks like, etc.

I have been scouring the web for something like this without much success (maybe I am looking in the wrong places), but since Celestia seems to contain all the underlying mechanics someone might have created a tool like this already.

I am only a beginner with celestial mechanics and the above would, of course, be the easiest way to achieve what I am after. If I am unlucky and no such luxurious add-on exists, I guess I will have to work it all out by myself. Does anyone know where I could find decent info on how to do that (links, books, anything really)? Or does anyone who know his stuff fancy creating such an add-on, maybe ?

Anyway, I hope some of you good people will be able to help me out,

All the Best & thanks in advance!

Unfortunately the tools to do this aren't quite as simple as you'd like. The easiest one to use that I've found is Swing-By by JAQAR.

http://www.jaqar.com/swingby.html

Unfortunately, its trajectory output is in heliocentric equatorial coordinates, while Celestia requires heliocentric ecliptic coordinates

The CalTech Mars Society has an orbit calculator for Earth-Mars trajectories, but it isn't quite as accurate as one would like. Also, it works with Internet Explorer, but not with Firefox.
http://meridiani2.usc.edu/trajcalc.html

(The server has been down for some time, but the page is still available from Google's cache at http://209.85.129.104/search?q=cache:th ... =clnk&cd=1 )

Most of the professional tools cost $$$$ or require extensive knowledge of their internal operations before they can be used.

The Java Astrodynamics Toolkit (JAT) project is working towards making this a possiblity. However, given that the project has limited (sporadic) funding we have been taking much longer than we would like to create this tool.

Right now, JAT has a large collection of powerful high-fidelity tools for computational astrodynamics. Unfortunately, you need to know about the mathematics (and Java) in order to use most of them. I managed to create a manageable trajectory for Selden, but creating 'realistic' trajectories to Europa is, to put it lightly, hard. Plus, coordinate frame issues are still troublesome when plotting interplanetary trajectories.

I have an old thread which talks about more details.
http://celestiaproject.net/forum/viewtopic.php?t=6188

JAT is available at
http://jat.sourceforge.net

If you would like some suggestions on a good text to get you started, I would suggest the follow two:

"Satellite Orbits" by Montenbruck and Gill
http://www.amazon.com/Satellite-Orbits- ... 354067280X

"Orbital Mechanics" by Prussing and Conway (professors of mine)
http://www.amazon.com/Orbital-Mechanics ... F8&s=books

The topic you will probably want to look at is called "Lambert Targeting" or "Lambert's Problem".