Have you seen this one:
http://astrojava.com/btp/. You might want to look at what features it has. I've used it but it has also has some miss-features/bugs/annoyances; I'm hoping yours is better
Yes I have, but I had much of the same grievances as everybody else seems to have had. I also wanted to make something that could give you more information that is orbiter specific such as the outward, prograde, and plane-change values needed for transX, and also something that could display plots for both "lowest departure deltaV" and "lowest approach deltaV." Most pork-chop plot generators I've seen (namely the above) only do the first, which isn't very usefull when you are primarily concerned with concerving fuel on orbital insertion.
Another big qualm I had with btc, is that I could only use the ones already inputed into the program, I couldn't put my own elements into it. That really surprised me, because if you can do all the other calculations, converting from kepler elements into state vectors should be a piece of cake.
Any chance it could support a mid-course plane change ala IMFD?
Probably not, since the whole point of doing it this way is to find the best trajectory without doing any additional burns.
Currently I'm looking at implementing VSOP87 into the program so I can do accurate departure/arrival calculations with the planets. I already found some nice visual basic modules that output most of what I want. They output celestial longitude, latitude, and radius in AU, but converting those to x,y,z and calculating velocity should be fairly easy.
I also changed the axis to departure date by flight time (like btc), instead of departure date by arrival date (which is the way most NASA generated plots I've seen). But I'll probably make it so the user can choose how he/she wants to display it.
If anybody has any requests/ideas for it, feel free to give them (like I could stop anybody
).