Project Low-Thrust Trajectory Planner

[Piper]

When of the most notoriously difficult things to do in Orbiter is the navigation and flight of low-thrust spacecraft (ie, ion-thrusters) like Dawn, Hayabusa, or Deep Space 1. So to go along with my regular [ame="http://www.orbithangar.com/searchid.php?ID=4439"]Trajectory Planner[/ame], I've made a program for designing trajectories for low-thrust spacecraft like my [ame="http://www.orbithangar.com/searchid.php?ID=789"]Chapman Ion[/ame] probes. Because of the more technical nature of this program, and the greater option in it, I've included a .pdf guide in this beta.

This program is definitely for the advanced orbitnaut. But if you are like me, and want to include flying ion-engine spacecraft in your Orbiter experience, then try this program out, and tell me what you think.

Special note, the burn values are based on TransX standards, if you use IMFD, switch the sign on the outward value since IMFD uses inward (Vi) instead of outward.

LTTPlanner.zip (1.43mb)

NOTE: Some people have reported issues when downloading this file. To successfully download it, right-click on the file and select 'Save Target As' or equivalent.

 

[tblaxland]

I need to play with this some more, but first attempts look good :thumbup:. Good work, Piper.

 

[BrianJ]

Fabuloso!! Can't wait to get home to check it out! :thumbup:

 

[jedidia]

WOOHOOT! It 's about time someone did something about that! going to try it out right away!

edit: tried around with it a bit, looks like a nice programm. Unfortunately I don't have the time right now to figure everything out. My first ejection burn didn't actually eject me, will have to try that again with a bit more delta-V.

One thing that strikes me as odd, though: the program gives me prograde and plane change velocities without actually knowing my orbit. Is it assuming a standard optimal orbit around earth? if yes, what would that be?

 

[Piper]

....One thing that strikes me as odd, though: the program gives me prograde and plane change velocities without actually knowing my orbit. Is it assuming a standard optimal orbit around earth? if yes, what would that be?

Actually, those are prograde, outward, and plane change RELATIVE to the orbit of the Earth. Stick these into TransX, and it will tell you what orbit you the different holding orbits to get into.

 

[jedidia]

ah... long time since I used transX. What would be the procedure with the Delta-V program of IMFD?

 

[flytandem]

Thanks Piper. Filling a definite need for sure.:thumbup:

 

[astrosammy]

ah... long time since I used transX. What would be the procedure with the Delta-V program of IMFD?

Well, I never tried it, but for the ejection the first thing I think of is entering the velocities and date from the planner into the Delta-V program. Set Earth as source, and then use the Orbit-Eject program to perform the burn.

For the low-thrust burns enter the velocities and use the Delta-V program together with [ame="http://www.orbithangar.com/searchid.php?ID=3815"]IEAT MFD[/ame].

 

[jedidia]

Well, I never tried it, but for the ejection the first thing I think of is entering the velocities and date from the planner into the Delta-V program. Set Earth as source, and then use the Orbit-Eject program to perform the burn.

ummm... does that mean that the ejection burn can't be performed on low thrust? that would be kind of a pitty, since it leaves one of the biggest problems still unsolved...
(Now that I think about it, I read something in the manual along those lines, but I thought it was optional...)

another small question just popped up. As far as I can see, the planer per se works totally on its own (i.e., it doesn't have to be put into the orbiter directory in order to work). That would mean that it wouldn't work with other solar system configurations, or custom systems, right? If it's possible to load the data directly from an orbiter system cfg, that would enhance the versatility of the program by quite some amount.

 

[Piper]

ummm... does that mean that the ejection burn can't be performed on low thrust? that would be kind of a pitty, since it leaves one of the biggest problems still unsolved...
(Now that I think about it, I read something in the manual along those lines, but I thought it was optional...)

Actually, there's a way you can, just set your ejection burn to 0, and set up your scenario so you depart the planet/object's sphere of influence on that date. This works great with asteroids, but I do not recommend doing this with planets.

another small question just popped up. As far as I can see, the planer per se works totally on its own (i.e., it doesn't have to be put into the orbiter directory in order to work). That would mean that it wouldn't work with other solar system configurations, or custom systems, right? If it's possible to load the data directly from an orbiter system cfg, that would enhance the versatility of the program by quite some amount.

I've thought about doing just that, and I may do it in the future. Same thing with my regular Trajectory Planner.

 

[jedidia]

Actually, there's a way you can, just set your ejection burn to 0, and set up your scenario so you depart the planet/object's sphere of influence on that date. This works great with asteroids, but I do not recommend doing this with planets.

The program seems to work nicely, now I'm motivated to find some better orbit eject procedures... :tiphat:

I've thought about doing just that, and I may do it in the future. Same thing with my regular Trajectory Planner.

That would be really great, since I intend to travel my orbiter galaxy by fusion drive, once it's finished.


Edit:

Oooops, I just tried to calculate a trajectory with more than one burn (2) for the first time. The calculator hangs before finishing the first generation (cancel doesn't respond anymore either, but it still shuts down nicely). everything works fine and pretty fast with only one burn. any Idea what the cause might be?

 

[Piper]

.....Oooops, I just tried to calculate a trajectory with more than one burn (2) for the first time. The calculator hangs before finishing the first generation (cancel doesn't respond anymore either, but it still shuts down nicely). everything works fine and pretty fast with only one burn. any Idea what the cause might be?

hmmmmm, I thought I fixed that . I'll check into it.

 

[Wishbone]

Piper, this needs uploading to OHM. I came upon this thread by chance (thanks to BrianJ for the tip), and your program will be lost to posterity if not uploaded... Just my 2 cents...

---------- Post added at 01:39 PM ---------- Previous post was at 01:20 PM ----------

Another problem: your web server treats zips as HTML, with me being on dial-up, I cannot re-start the download, so it would take ages to d/l the file.

 

[boogabooga]

Having a problem at start up of this program on both a Windows XP machine and a Windows 8.1 machine:

COMDLG32.OCX or one of its dependents not correctly registered: a file is missing or invalid

 

[IronRain]

http://lmgtfy.com/?q=COMDLG32.OCX+missing

 

[Ripley]

Piper, this needs uploading to OHM. I came upon this thread by chance (thanks to BrianJ for the tip), and your program will be lost to posterity if not uploaded... Just my 2 cents...

:hesaid:

 

[Piper]

I can definitely upload the current program to OHM, if everybody wishes, but the program was written back in the days of VB6, so it isn't exactly workable on everyone's computers right now.

I am currently re-writing the program from scratch in VB2010. I still have all the raw code (I really wish there was a way I could just open the old one and save it as a new project in VB2010), so a lot of it will just be cut and paste, but of course it will have to be all updated.

While I'm re-writing it, I would love to hear some recommendations, reviews, and opinions on what I do have up. After running the program for the first time in at least 2 years, I already can see a bunch of things I want to change, but I really want to hear from others what their opinions and experiences with it are.

 

[MaverickSawyer]

Periapsis kick planner. For those REALLY low TWR craft.

 

[Furet]

Thank you so much for this tool.:tiphat:

While I'm re-writing it, I would love to hear some recommendations, reviews, and opinions on what I do have up. After running the program for the first time in at least 2 years, I already can see a bunch of things I want to change, but I really want to hear from others what their opinions and experiences with it are.

A little compatibility issue I guess: impossible to launch the program or load a saved files without changing the regional settings (commas for decimal are causing a crash).

 

[Piper]

Thank you so much for this tool.:tiphat:



A little compatibility issue I guess: impossible to launch the program or load a saved files without changing the regional settings (commas for decimal are causing a crash).

Ya, that is something I'll be addressing in the new version (I recognize it may be a problem with some of my other programs as well). The new version is coming along well, the form is done and I have begun transfering and converting code from the old one to the new one. I haven't had a lot of time to work on it lately, but starting March I'll be working at a different post, and with it being all evenings and nights, I'll have TONS of time to work on this and all my other Orbiter projects that I've been wanting to work on but haven't had the time.