Spacecraft course plotting tool?

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eltoddi
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Joined: 14.10.2006
With us: 18 years 1 month
Location: Friedrichshafen, Germany

Spacecraft course plotting tool?

Post #1by eltoddi » 15.10.2006, 12:32

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!
...
And all that is now,
And all that is gone,
And all that's to come,
And everything under the sun is in tune,
But the sun is eclipsed by the moon.

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selden
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Post #2by selden » 15.10.2006, 12:57

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.
Selden

Apollonian
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Post #3by Apollonian » 16.10.2006, 20:25

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".


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